Psychosexual Functioning of Cognitively-able Adolescents with Autism Spectrum Disorder Compared to Typically Developing Peers: The Development and Testing of the Teen Transition Inventory- a Self- and Parent Report Questionnaire on Psychosexual Functioning
J Autism Dev Disord
Psychosexual Functioning of Cognitively-able Adolescents with Autism Spectrum Disorder Compared to Typically Developing Peers: The Development and Testing of the Teen Transition Inventory- a Self- and Parent Report Questionnaire on Psychosexual Functioning
Linda P. Dekker 0
Esther J. M. van der Vegt 0
Jan van der Ende 0
Nouchka Tick 0
Anneke Louwerse 0
Athanasios Maras 0
Frank C. Verhulst 0
Kirstin Greaves-Lord 0
0 Yulius Academy & Yulius Autism , Yulius, Mental Health Organisation, Dennenhout 1, 2994 GC Barendrecht , The Netherlands
1 Linda P. Dekker
To gain further insight into psychosexual functioning, including behaviors, intrapersonal and interpersonal aspects, in adolescents with Autism Spectrum Disorder (ASD), comprehensive, multi-informant measures are needed. This study describes (1) the development of a new measure of psychosexual functioning in both parentand self-reports (Teen Transition Inventory; TTI) covering all three domains of psychosexual functioning (i.e. psychosexual socialization, psychosexual selfhood, and sexual/ intimate behavior). And (2) the initial testing of this instrument, comparing adolescents with ASD (n = 79 parentreport; n = 58 self-report) to Typically Developing (TD) adolescents (n = 131 parent-report; n = 91 self-report) while taking into account gender as a covariate. Results from both informants indicate more difficulties regarding psychosexual socialization and psychosexual selfhood in the ASD group. With regard to sexual/intimate behavior, only parents reported significantly more problems in adolescents with ASD.
Psychosexual; Autism spectrum disorder; Adolescence; Comprehensive measure; Typically developing
Published online: 16 March 2017
© The Author(s) 2017. This article is published with open access at Springerlink.com
Department of Child and Adolescent Psychiatry/psychology,
Erasmus MC-Sophia, Wytemaweg 8, Room KP 2881,
3015 CN Rotterdam, The Netherlands
In the past few years, psychosexual functioning in
adolescents with ASD has become an increasingly studied topic
(e.g. Dewinter et al. 2014, 2016; Ginevra et al.
2015; Gougeon 2010; Kellaher 2015; Mehzabin and Stokes
. Psychosexual functioning covers not only sexual
behaviors, but also interpersonal (i.e. psychosexual
socialization; for example relationships) and intrapersonal (i.e.
psychosexual selfhood) dimensions
(Dewinter et al. 2013)
Although not necessary, the interpersonal and intrapersonal
elements may be the basis for a healthy overall
(O’Sullivan et al. 2007)
. For example,
having a crush, or developing a relationship with someone and
having sexual desires, may be the foundation for the
development of partnered sexual behavior
(Hearn et al. 2003)
although this has not be studied in individuals with ASD.
Much research into psychosexual functioning in individuals
with ASD has focused on problematic aspects, using
primarily parent or clinician report. For example; autistic traits
have been related to excessively thinking about sex, public
masturbation, stalking and sexual offenses (i.e. both as
victim and as perpetrator)
(e.g. Dekker et al. 2014; Dewinter
et al. 2013; Hellemans et al. 2007; Sevlever et al. 2013;
Stokes and Kaur 2005; t Hart-Kerkhoffs et al. 2009)
However, there is also research into psychosexual functioning
in individuals with ASD which has focused on the typical
aspects, using mostly self-report. This research has shown
that individuals with ASD have sexual needs and desires,
are interested in romantic relationships and have similar
socially accepted experiences and behaviors compared to
(Dewinter et al. 2014; Gilmour et al. 2012;
Hénault 2006; Kellaher 2015; Stokes et al. 2007)
. It is
valuable to expand the acquired knowledge on psychosexual
functioning in adolescents with ASD and obtain
information from multiple informants in all domains of
psychosexual functioning. This can provide a more well-rounded and
multi-dimensional perspective on psychosexual functioning
in individuals with ASD.
Psychosexual functioning can be divided into three
domains: psychosexual socialization (interpersonal),
psychosexual selfhood (intrapersonal), and sexual/intimate
(Dewinter et al. 2013; Tolman and McClelland
. Psychosexual socialization includes the
interaction with social contexts (e.g. peers, parents, siblings, and
media) in which individuals learn about and experience
relationships and sexuality. Psychosexual selfhood relates
to the intrapersonal functioning including self-esteem,
selfperceived competence, and knowledge. Sexual/intimate
behavior includes a continuum of sexualized behaviors and
experiences, ranging from typical, age-appropriate
behaviors to atypical, inappropriate or even illegitimate
behaviors. Unfortunately, in the current literature on individuals
with ASD, most of the studies on (psycho)sexual
socialization have primarily used parent or caregiver report,
psychosexual selfhood is generally understudied, and when
selfreport was used the focus was solely on sexual behavior
(Dewinter et al. 2013; Fenton et al. 2001)
The usage of either self-report or other-report may be
related to issues of assumed insight and knowledge
regarding the topic of research and/or the capacity to report
reliably on the topic. At least in Typically Developing (TD)
(Fenton et al. 2001)
, typical and socially
accepted aspects of psychosexual functioning are often
considered fairly private. Therefore, others are thought to
not be optimal informants about these topics, which may
have led to primarily using self-report. The limited use of
self-report in the other domains in the current literature on
psychosexual functioning in ASD
(see for reviews Byers
et al. 2013; Dewinter et al. 2013; Gougeon 2010)
because the reliability and validity of self-report in
individuals with ASD has been questioned
(Cederlund et al. 2010;
Urbano et al. 2013)
. Most likely the use of clinician or
parent report stems from the assumption that individuals with
ASD have little insight into the problematic aspects.
However, even with regard to overt topics, such as behavior, a
recent study of Dewinter et al. (2016) showed that parents
and adolescents do not report identically, implying that
the type of informant may influence the results and thus
the conclusions. To conclude, parents or clinicians may
be better to report on some issues requiring difficult social
insight. However, adding self-report also provides
meaningful information, namely the adolescents own perspective
on their psychosexual functioning (i.e. psychosexual
socialization and psychosexual selfhood) and their private
experiences (i.e. sexual/intimate behaviors) (Lerner et al. 2012).
When it comes to psychosexual functioning in individuals
with ASD, the use of multiple informants seems valuable
to get a more complete picture as well as insight into how
the informant is experiencing psychosexual functioning.
Besides the limited use of multiple informants, few
studies have directly compared the psychosexual functioning of
adolescents with ASD to a TD control group. This has
limited the ability to compare psychosexual functioning in the
two groups and investigate the influence of ASD on
psychosexual functioning. A comprehensive measure designed
for multiple informants which gives insights into the
functioning on all three domains of psychosexual functioning
used in both an ASD and TD group, would provide data to
compare the two groups, thus giving insight into the
potential differences and difficulties related to ASD.
As psychosexual functioning is a complex, multifaceted
(World Health Organization 2006)
, this in turn
has complicated the development of a questionnaire which
covers all domains and is suitable for multiple informants.
Many currently existing questionnaires only cover one
domain of psychosexual functioning or are not suitable for
multiple informants. Therefore, in an attempt to add to the
growing body of research on psychosexual functioning in
adolescents with ASD, we developed the Teen Transition
Inventory (TTI; for a detailed description see
Measurements) for the purpose of this study. In the development
of this tool, we adopted the broad definition of
psychosexual functioning described before, covering the three
domains: psychosexual socialization, psychosexual
selfhood, and sexual/intimate behavior
(Dewinter et al. 2013;
Tolman and McClelland 2011)
. Items regarding the first
domain, i.e. psychosexual socialization, inquire for
example into the skills related to social and intimate contact,
openness regarding intimacy and dealing with boundaries.
This domain distinguishes between more basic social skills
(e.g. Friendship Skills and Social Acceptance) that form a
prerequisite for more complex intimate social skills (e.g.
Romantic skills). Existing questionnaires on social
qualities of individuals with ASD, e.g. the Social
Responsiveness Scale (Constantino and Gruber 2007) focus mainly on
known autistic difficulties in social relations. In the TTI the
focus is more on typical basic and complex intimate social
skills that are the basis for healthy psychosexual
functioning. Items regarding the second domain, psychosexual
selfhood, seek to get information for example about sexual
preference, body image, the level of self-esteem, desires,
self-perception, and psychosexual knowledge. Questions
in the third domain, sexual/intimate behavior, entail the
behavioral repertoire that people have with regard to
sexuality both online and offline, covering appropriate and
inappropriate sexualized behavior (including the amount
and type of behaviors), and the age of onset. Moreover,
we developed the TTI in both a self-report and a
parentreport version. However, in line with previous research,
some items are only posed in the TTI of one informant, as
we expected the other informant to not be able to reliably
answer some items (for example items regarding
appropriately dealing with boundaries was only asked to parents and
general self-esteem was only part of the self-report TTI).
In the current paper we describe the development of the
TTI. Which was specifically developed for the purpose of
this study, to allow us to compare all aspects of
psychosexual functioning of cognitively-able adolescents with ASD
to TD adolescents. In addition, the initial testing of the TTI
is discussed, involving (1) the pilot testing of the internal
consistency of the theoretically constructed scales
regarding psychosexual functioning, and (2) examining whether
the scales and items of the TTI distinguish between
cognitively-able adolescents with ASD versus their TD peers.
Based on previous literature, we hypothesized that
cognitively-able adolescents with ASD compared to their TD
peers have less psychosexual socialization (e.g. less social
acceptance and less adequately dealing with boundaries),
poorer psychosexual selfhood (e.g. poorer body image, less
confidence, less perceived social competence, lower
selfesteem and less knowledge despite equal social, romantic
and sexual desires), and display more inappropriate
sexualized behaviors, but have similar experiences with
appropriate sexual/intimate behaviors
(e.g. Brown-Lavoie et al.
2014; Dewinter et al. 2014; Kasari et al. 2011; Nichols and
Blakeley-Smith 2009; Stokes et al. 2007)
. Given the fact
that previous studies only used one informant (i.e. either
parent or self-report), we were particularly interested to see
whether these hypotheses would be confirmed using both
parent- and self-report.
Sample & Procedure
Between 2011 and 2012, Data for this Study were
Collected from an ASD Group and a TD Group
The ASD group (n = 79) was selected from a larger clinical
sample from the outpatient’s Department of Child and
Adolescent Psychiatry/psychology of the Erasmus MC—Sophia
in Rotterdam, the Netherlands who were participating in a
follow-up study. In the initial study between July 2002 and
September 2004, 503 children were referred for
psychiatric evaluation. Of the 503 referrals, 234 children were
eligible to be included in the follow-up study approximately
7 years later due to their social and/or communication
problems during the first study
(Louwerse et al. 2015)
Of the 234 children, 104 (42.3%) children had a
best-estimate ASD diagnosis, which was based on the ADI-R and
ADOS (see ASD diagnostic procedure below) and thus
received the TTI to participate in this part of the study. 79
(76.0%) parents of the 104 individuals with a best-estimate
ASD diagnosis returned the Teen Transition Inventory
(TTI) parent-report. The parents who did return the TTI
did not significantly differ from the group of parents who
did not return the TTI with regard to the adolescent’s age
(t(102) = 1.50, p = .14), intelligence (t(75) = −0.39, p = .70)
or gender (χ2(1, n = 104) = 0.61, p = .44). Of the 79
individuals with parent-report, we received 58 (73.4%) self-report
TTI’s. The group without self-report data did not differ
significantly from the group with self-report data on age
(t(77) = 0.68, p = .50), intelligence (t(59) = −1.43, p = .16),
or gender (χ2(1, n = 79) = 0.46, p = .50), nor on any of the
parent-reported psychosexual scales (for a full description
of the scales see measurements: Teen Transition
Inventory). The mean age of the adolescents with ASD (n = 79)
was 16.79 years (range 13–21, SD = 2.05) and the majority
was male (86%). Please see Table 1 for all descriptive
characteristics of the ASD group.
The TD sample was drawn from a Dutch general
population study (n = 1710)
(Evans et al. 2012; Louwerse et al.
2013; Tick et al. 2008)
from which 326 individuals were
eligible to participate as they were between 12 and 21
(Evans et al. 2012)
. Of the 326 adolescent and
their parents who were contacted, 153 (47%) returned the
parent-report and 113 (35%) the self-report. To ensure the
TD group would be without autistic traits, we
additionally excluded individuals if they had elevated autistic traits
(n = 22) as assessed with the Autism Quotient (AQ;
BaronCohen et al. 2001
). The final number of included
participants; i.e. those who returned the TTI and without autistic
traits on the AQ, was 131 (40% of the originally selected
adolescents and 86% of those who returned the TTI). Of
the 131 participants with parent-report, 91 (=69.5%)
selfreport TTIs were returned. Those without self-report
data did not differ significantly from the group with
selfreport data on intelligence (t(118) = −0.66, p = .51), or
gender (χ2(1, n = 131) = 1.96, p = .16) and on seven of the
nine parent-reported psychosexual scales (see
Measurements: Teen Transition Inventory). However the group
with self-report data was significantly younger (M = 16.12,
SD = 1.47) than the group without self-report data
(M = 16.73, SD = 1.77; t(129) = 2.03, p = .04). In addition,
the group with self-report data had higher parent-reported
family openness regarding sexuality (M = 1.22, SD = 0.42)
than those without self-report (M = 0.98, SD = 0.40; t(126)
= −3.04, p < .01) and less parent-reported sexual
experiences (M = 0.48, SD = 0.37) than those without self-report
(M = 0.64, SD = 0.36; t(120) = 2.15, p = .03). The mean age
of the TD sample (n = 131) was 16.31 years (range 13–20,
SD = 1.59) and 46% of the sample was male. Table 1
provides descriptive information on the TD group.
To assure we were able to make a viable comparison
regarding psychosexual functioning between the ASD and
TD group, we ascertained whether the groups differed in
characteristics such as age, intelligence, physical
development and gender, to potentially control for these variables
in the main analyses (for further details, please see
section Statistical analyses). The results of these comparisons
are displayed in Table 1. The study was approved by the
Medical Ethical Review Committee of the Erasmus MC.
All parents and adolescents gave informed consent.
ASD Diagnostic Procedure
To obtain a best-estimate clinical diagnosis of ASD, the
Autism Diagnostic Interview Revised
(ADI-R; Rutter et al.
was performed with parents, and the Autism
Diagnostic Observation Schedule
(ADOS; Lord et al. 2000)
administered to the adolescents. The ADI-R and ADOS
were administered by examiners who had completed the
research-training and had achieved sufficient reliability
for administration and coding. Based on age and language
capability, module 4 of the ADOS was primarily used,
although for 6 participants the ADOS module 3 was used.
Both examiners reviewed DSM-IV-TR criteria of ASD (i.e.
Pervasive Developmental Disorder) and together obtained
a consensus diagnosis
(Falkmer et al. 2013)
32% of the ASD cases (n = 23) did not meet the diagnostic
cut-off of the ADOS, these cases received a best-estimate
clinical diagnosis based also on the information obtained
during the ADI-R.
Teen Transition Inventory—Measurement Development
General Description of the Teen Transition Inventory The
Teen Transition Inventory (TTI) was primarily developed for
the purpose of this study, which was to get a better insight in
the psychosexual functioning (i.e. psychosexual
socialization, psychosexual selfhood and sexual/intimate behavior)
of adolescents with ASD compared to TD adolescents. The
TTI is based and expanded upon previous research in the
field of psychosexual functioning in individuals with ASD
(see below). As psychosexuality may be experienced as a
rather delicate topic, and is probably related to more general
aspects of social and physical development, it was decided
to structure the TTI in such a way (i.e. build in subheadings)
that it starts with less intimate questions on more general
adolescent transition issues (such as the experience of the
transition to secondary school and building new friendships,
physical development, and leisure activities), followed by
the more personal questions on psychosexual functioning
(i.e. the bulk of the questionnaire, such as building
romantic relationships). As such, more intimate questions
regarding intimate relations build on similar questions regarding
friendship relations. In the section ‘Psychosexual
functioning in the Teen Transition Inventory’ a more in-depth
description of the psychosexual domains of the TTI is
The TTI is aimed at individuals between the ages of 12
and 21 years old. To obtain multiple perspectives, the TTI
consists of a parent-report version and a self-report version.
The parent-report TTI and self-report TTI have
considerable overlap in items and thus scales (see Table 2).
However, the parent-report TTI includes additional items and
scales on topics that parents were considered to be better
able to adequately judge (e.g. their child’s psychosexual
knowledge and the extent to which their child deals
appropriately with boundaries) and thus reliably report on. The
self-report TTI includes additional items and scales
compared to the parent-report TTI regarding very private and
subjective matters (e.g. age of onset of sexual/intimate
behavior and self-perceived social competence). In total,
the parent-report TTI consists of 148 items and the
selfreport TTI of 205 items. All scorings of the items are based
on information of the last six months to the current state of
the adolescent. Most of the items of the TTI are scored on a
3-point scale of ‘Not at all true’; ‘Somewhat or Sometimes
true’ and ‘Definitely or Often true’, with the exception of a
minority of items (e.g. age of onset and behaviors that can
only either be displayed or not, i.e. yes/no answering
format). Both the parent-report and self-report take
approximately 1 h to complete. The TTI is available upon request
(in Dutch, English, Greek and Spanish).
Development of the Teen Transition Inventory
The TTI was developed by a team of researchers and
clinicians of Erasmus MC—Sophia and Yulius with input from
adolescents with ASD and their parents. The researchers
who were involved the development of the TTI, had
previous research experience with the assessment of adolescents
with ASD and their caregivers. The clinicians involved in
the development of the TTI were psychologists, sexologists
and psychiatrists, who had specific clinical experience with
adolescents with ASD and psychosexual concerns. As a
first step, based on the earlier literature on sexuality in
individuals with ASD as well as gaps noticed in this research,
an initial list of questions, their scoring options, and
clustering was constructed by the researchers: i.e. covering the
topics of psychosexual socialization, psychosexual
selfhood and sexual/intimate behavior
(based on Gougeon
2010; Hellemans et al. 2007, 2010; Hénault 2006; Koller
2000; Locke et al. 2010; Nichols and Blakeley-Smith 2009;
Realmuto and Ruble 1999; Stokes and Kaur 2005; Stokes
et al. 2007; Sullivan and Caterino 2008; t Hart-Kerkhoffs
et al. 2009; Tolman and McClelland 2011)
. In the
second step, these items, options and their clustering were
reviewed by the clinicians, who suggested some changes in
(particularly with regard to taking the
wording too literal, which some individuals with ASD do;
e.g.Dennis et al. 2001; Martin and McDonald 2004)
also suggested the addition of items; i.e. questions
regarding inappropriate love interests (e.g. a teacher, therapist or
group-leader). After the suggested changes were made, in a
third step this revised version of the TTI was piloted during
a pilot study to include the input of 12–18 years old
adolescents with ASD and their parents, who also participated in
a study on the effects of a psychosexual intervention
(Tackling Teenage). Participants (N = 30) were asked to fill out
the TTI and provide it with their written feedback,
including open-ended alternative answering options as well as an
open page on which participants could provide their
suggestions. Also, oral feedback was welcomed, in case
preferred. The use of the TTI in the pilot study was undertaken
to specifically evaluate the TTI for use among adolescents
with ASD and their parents, to ensure that the questions
were relevant, clear and understandable for individuals
with ASD and their parents. In addition, the pilot allowed
us to examine whether the content, covering rather private
topics, was experienced as too personal which could lead
to people not filling out questions. The pilot ensured that
this was not the case, since all participants returned the TTI
fully answered. The feedback uncovered that the content of
the TTI was experienced as asking quite personal
information, and some found it difficult to think of answers as they
never consciously thought about these issues before. Yet
no feedback was given that topics should be excluded for
the reason of being too personal or that other topics should
be included. Remaining feedback varied from
suggesting changes in the answering options (i.e. hair growth can
never be done, thus the answer option was changed from
‘finished’ to ‘full-grown’) to suggesting shortening of the
introductory texts on the topics of the TTI. The feedback of
the clients and their parents was used to further improve the
TTI. As a final step, the researchers optimized the initial
TTI scales based on the state-of-the art literature.
Psychosexual Functioning in the Teen Transition Inventory
Psychosexual functioning (i.e. psychosexual
socialization, psychosexual selfhood and sexual/intimate behavior)
is covered by a total of 81 items in the parent-report TTI
and 123 items in the self-report TTI. Table 2 illustrates
the scale structure of the TTI divided per domain of
psychosexual functioning, and provides examples of items for
each subscale (a sample of the TTI is provided in appendix
1a + b). As shown, 48 of the items of the parent-report are
clustered into 9 scales, with the remaining 33 items used
as ‘stand-alone’ items. Of the self-report 69 of the items
are clustered into 12 scales, with the remaining 54 items
left as ‘stand-alone’ dichotomous variables. ‘Stand-alone’
items reflect the presence or absence of particular
behaviors, experiences or qualities that could not be
meaningfully clustered into scales (e.g. My child has been in love
nd ie m / y
ifre ffr sho and hm
g o ti s ti
in pu w gn w
ak ro ev lie ity
g lo fe la
ta fa in y xu
od tr ’m do sm /se I I
o a I s y T T
agm apm ehn ttaho iscdu itcam troT troT
.I .I .W w .I in rep rep
,.eg ,.eg ,.eg now ,.eg tou lf-se lf-se
I s s s k s ab
with a celebrity; I think it is important that my best friend
is funny) and were therefore used dichotomously. Any
stand-alone item scored on a 3-point scale, was first
dichotomized before further analyses. The categories ‘Somewhat
or sometimes true’ and ‘Definitely or often true’ were then
collapsed into one category and coded as 1 whereas the
category ‘Not at all true’ was coded as 0.
Based on the existing literature and on expert opinion,
the scales were formed using items that reflect a particular
(e.g. Dewinter et al. 2013; Realmuto
and Ruble 1999; Tolman and McClelland 2011; Urbano
et al. 2013)
. Scale scores are computed by calculating the
mean score of all the items on the scale that were filled out,
where a minimum of 60% of the items in the scale have to
be filled out. Thus, the scale scores reflect the mean score
of the items on the scale, either of the parent or the
adolescent. Most scale scores range between 0 and 2 except the
scales in the sexual/intimate behavior domain (i.e. ‘Amount
of sexual/intimate behavior’; ‘Amount of inappropriate
sexualized behavior’ and ‘Online sexual activity’) which range
between 0 and 1. As behaviors and experiences are
considered to either have or have not occurred, most items on the
scale were dichotomous, and thus all items on these scales
were used as dichotomous items to compute the mean scale
Previous studies have related age, gender, intelligence and
physical development (i.e. Tanner stages) to psychosexual
functioning and to ASD
(e.g. Baron-Cohen and
Wheelwright 2003; Beier and Ackerman 2003; Flannery et al.
1993; Halpern et al. 1993; Mandy et al. 2012; Shandra
and Chowdhury 2012; Stokes et al. 2007; Vickerstaff et al.
2007; Whitehouse et al. 2011)
. Therefore, it was important
to assess these variables.
As measures for intelligence we used abbreviated
versions of the Wechsler intelligence scales. In the ASD
sample the Wechsler Abbreviated Scale of Intelligence
was used. The full 4 score of the WASI
(i.e. using all of the 4 subtests) was used as a total IQ score.
In the TD sample, two subtests of the Wechsler Intelligence
Scale for Children were used, namely vocabulary and block
(WISC; Wechsler 2004)
. On both subtests a score of
y 10 reflects average intelligence. A total IQ score was
tno culated for the TD sample by computing the mean scores,
v transforming this into z-scores, and then transforming the
iitsnno szt-asncodraerdtodeavtioattaiolnIQ. score with 100 as a mean and 15 as the
raT The Tanner stages are a staging system which uses
scheeen matic drawings of secondary sexual characteristics divided
IT into five standard stages
(Marshall and Tanner 1969, 1970)
TT In our study we used the parent-rated Tanner stages. The
primary caregiver, in our study mostly the biological
mother (86%), indicated on the gender appropriate sketches
which stage resembled the physical appearance of her child
most. The ratings have shown good reliability and validity
and have been used widely (Dorn et al. 1990).
For descriptive purposes, we computed means and standard
deviations on age, intelligence, and parent-reported Tanner
stages and the frequency of gender for the group with ASD
and the TD group. For the ASD group, we also computed
descriptive scores on the ADI-R
(Rutter et al. 2003)
severity score on the ADOS
(Lord et al. 2000)
, to provide
an indication of the ASD severity in our sample. To
investigate which of the putative covariates should be included
in the main analyses, we examined whether our groups
differed on these variables. For age, IQ and tanner stages
this was done by means of independent-samples t tests,
gender was compared by means of chi square analyses. In
addition, we computed correlations between the potential
covariates and all scales of the TTI. An association of the
potential covariate with group status (ASD versus TD) as
well as an outcome measure resulted in the inclusion of
this variable as a covariate in the main analyses (i.e. group
The primary aims of the current paper were to describe
the development of the TTI and to compare psychosexual
functioning of adolescents with ASD to TD adolescents.
For this purpose, we firstly examined the internal
consistency of the scales and correlations between scales, and
secondly explored the differences between adolescents
with ASD and TD adolescents with regard to psychosexual
functioning using the TTI.
Measurement Development: Internal consistency
The internal consistency of the scales of the TTI, which
were theoretically constructed based upon the available
literature and clinical experience of the team developing
the TTI, were checked by means of Cronbach’s alpha. The
Cronbach’s alphas were calculated separately for the ASD
sample and for the TD sample. Items on the scales were
checked to have an item-rest correlation of at least 0.3 in
at least one of the samples, which indicates that the item
measures the same underlying construct
Items that did not meet this criteria were subsequently
either retained or removed from the scale based on their
content validity and the effect on the Cronbach’s alpha of
the scale. If the deletion of an item let to an improvement
of 0.1 or more in the Cronbach’s alpha’s in both samples
the item was removed from the scale.
Measurement Development: Correlations Between Scales
We also ran correlations between the various scales of both
self-report and parent-report. Any perfect or near to perfect
correlations (> ± 0.90) were considered for data reduction
purposes. If the correlation in combination with content
seemed to reflect that the scales measured the same
construct, this could indicate a scale could be excluded. In
addition, the correlations provide insight in how the
different domains of psychosexual functioning interrelate and
show the associations between self-report and parent-report
ASD versus TD: Group Comparisons
Group comparisons regarding psychosexual functioning
were made using analyses of variance adjusted for any
relevant covariate (ANCOVA; i.e. for scale scores) or
logistic regression analyses (i.e. for categorical separate item
scores). For continuous outcomes, e.g. scores on the scales
and age variables, group membership (ASD or TD) was the
between-subjects factor. For the categorical outcomes, i.e.
the dichotomous separate items, we investigated differences
between ASD and TD again including any relevant
covariate as predictors. Items which showed a significant
difference between the ASD sample and the TD sample were
subsequently analyzed for frequencies, to investigate which
percentage of the groups had that experience.
Since we ran multiple tests to investigate similarities
and differences in psychosexual functioning between the
adolescents with ASD versus TD adolescents, we used
the Bonferroni correction for multiple testing in the group
comparison analyses. In the parent-reported data we ran 42
analyses (9 on the scales and 33 on the dichotomous
separate items), therefore the appropriate p-value to control for
Type I errors is 0.0012 (is 0.05/42). In the self-reported
data we ran 65 tests (12 on the scales and 54 on the
dichotomous separate items), therefore the appropriate p-value
after the Bonferroni correction is 0.0008 (is 0.05/66).
The main characteristics of the ASD and TD samples
are shown in Table 1. Only gender significantly differed
between the group with ASD and the TD group, in which
the ASD sample had significantly more males than the
TD sample. Correlations between the scales of the TTI
and potential covariates per group showed that some of
the potential covariates were significantly related to some
of the scales (see Tables 3, 4). However, since gender was
the only variable related to both group status and outcome
measures, only this variable was included as a covariate in
all the main analyses.
Measurement development: Internal consistency
One of the goals of the current study was to pilot test the
internal consistency of the TTI scales (see Table 5). For
each scale the internal consistency was calculated and the
item-rest correlations were checked to see if any item on
any scale was below 0.3 in both samples. Based on the
number of items in each scale, and the number of
participants, five of the nine parent-scales and ten of the twelve
adolescent-scales showed good (i.e. >=0.7) internal
consistency in at least one of our samples (see Table 5 for the
respective Cronbach’s alphas; Field 2013;
Ponterotto and Ruck
). In addition, three of nine
parent-scales showed moderate (>0.55) internal
; Ponterotto and Ruck
two scales showed low (i.e. <0.5). internal consistency.
One in both parent-report and self-report (i.e. Amount of
inappropriate sexualized behavior) and one only in
selfreport (Personal openness about intimacy).
Based on the analyses to check the Cronbach’s alpha,
15 items (six items on parent-report scales and nine items
in the self-report scales) showed an item-rest correlation
below 0.3 in both samples. Please see specifications in
appendix 2. Although an item-rest correlation below 0.3
may indicate that the item does not belong to the scale, all
off the items were retained on their respective scales for
two reasons. Firstly, removal of the items resulted in
minimal improvements of the Cronbach’s alpha (less than 0.1
in both samples), or even decreased the Cronbach’s alpha.
Secondly, as this pilot study is the first using the TTI and
the Cronbach’s alpha is dependent on sample size and
characteristics, removing the items based on these first results
in the current sample seems too premature. Current sample
sizes are insufficient to run confirmatory factor analyses,
which would have been a better way to study the reliability
of the questionnaire. Further research with the TTI is on its
way to improve its psychometric underpinnings.
Measurement Development: Correlations Between
Correlations between the scale-scores of both informants
(self-report and parent-report) showed a wide variety of
correlational strength (see Table 6). Most of the
correlations are non-significant (n= 69.3%) and represent
negligible (0.00 to ±0.10) or small correlations (0.10 to ±.0.30).
Of the correlations that do reach significance (n = 117), the
majority (n = 59 = 50.4%) can be qualified as medium effect
(>±0.30) and 24 correlation (20.5%) have large effect
. None of the correlations were
perfect or near perfect (>±0.90). Thus, there were no
correlations which merited data reduction. The correlations were
mostly in the expected directions and between scales that
were expected to be closely related (e.g. Social Acceptance
and Friendship Skills), both within informant and between
informants. Only one scale stood out in this respect, i.e. the
Romantic Skills scale, which unexpectedly correlated
negatively with the majority of the scales on the TTI (both
selfreport and parent-report). Correlations between informants
showed that, in both the ASD and TD group, on all but the
scale of Inappropriate Sexualized Behavior the correlations
ASD versus TD: Group Comparisons
Table 7 shows the results regarding the domain
psychosexual socialization. Significant differences, based on both
self-report and parent-report, between adolescents with
ASD and TD adolescents are found on three of the scales
(i.e. ‘Friendship skills’, ‘Social acceptance by peers’ and
‘Adequately dealing with boundaries’). Adolescents with
ASD have more problems with peers than the TD
adolescents. The other scales (i.e. ‘Romantic skills, ‘Family
openness about intimacy’ and ‘Personal openness about
intimacy’) showed no significant group differences.
Due to the large number of separate items in the
psychosexual selfhood domain (n = 7 in the parent-report and n = 21
in the self-report), only those items which significantly
differed between the two groups are reported in Table 8.
Significant differences between the adolescents with ASD and
their TD peers were found with regard to the scales ‘Sexual
knowledge’, ‘Self-esteem’ and ‘Perceived social
competence’ (the latter both on the self-report and parent-report).
Only parents reported a significant difference on the scale
‘Body image’. No significant differences were found with
regard to ‘Romantic confidence’, ‘Social desires’,
‘Romantic desires’ and ‘Sexual preference’ (i.e. hetero- or
homosexual love interests).
The results regarding Sexual/intimate behavior are shown
in Table 9. Again, only items which significantly differed
between the ASD group and the TD group were reported
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in Table 9. When considering self-report, no significant
differences were reported; indicating that according to
self-report adolescents with ASD functioned similarly in
the domain of Sexual/intimate behavior as their TD peers.
However, significant differences between the adolescents
with ASD and their TD peers were found when
considering the parent-reported scales ‘Amount of sexual/intimate
behavior’ and ‘Amount of inappropriate sexualized
behavior’. These results indicated less experience with typical
sexual/intimate behaviors (e.g. French-kissing), and more
inappropriate sexualized behaviors in the adolescents with
ASD. In addition, parents reported significant differences
in some types of sexual/ intimate behaviors, particularly
related to allowing and seeking physical contact with
family-members or well-known acquaintances, and taking
initiative to seek physical contact with less known
acquaintances/strangers. No significant differences were found with
regard to age of onset for sexual/intimate behaviors
(selfreport only), online sexual activity, a variety of types of
sexual/intimate behavior (see Table 2 for examples) and the
length of the current relationship or age of the current
partner (both parent and self-report) .
In our main analyses only gender qualified to be taken
into account as a covariate. Although none of the other
covariates merited to be taken into account in our analyses,
for good measure we additionally ran all the analyses in all
three domains including all covariates (i.e. gender, age, IQ
and Tanner stages). These analyses yielded very similar
Research on psychosexual functioning in individuals with
ASD is steadily growing, uncovering more and more
information. However, much research has been done with only
one informant, not covering all domains of
psychosexual functioning or without including a TD control group.
Therefore, the current paper aimed to describe the
development of comprehensive measure of psychosexual
functioning, the TTI, and the initial testing of the TTI. The measure
was developed for the purpose of this study, i.e. to
compare psychosexual functioning of adolescents with ASD to
TD adolescents. Subsequently, we tested the internal
consistency of the scales on the TTI and tested whether the
TTI distinguished between adolescents with ASD and TD
The TTI covers all three domains of psychosexual
functioning (i.e. psychosexual socialization, psychosexual selfhood,
and sexual/intimate behavior) and uses multiple
informants. By creating a parent-report and self-report version of
the TTI, we were able to get both the perspective of the
caregiver as well as the adolescent, which, to our knowledge,
was not yet combined in previous studies, highlighting
the significance of the current report. During the
development of the TTI we took into account results from previous
research and attempted to combine constructs into a
questionnaire covering all 3 domains of psychosexual
functioning, while also making the questionnaire suitable for
multiple informants. Of the 9 parent-report and 12 self-report
psychosexual scales of the TTI, that were theoretically
constructed, most (89% of the parent-report and 83% of
the self-report) showed moderate to good internal
; Ponterotto and Ruck
scales (i.e. ‘Amount of inappropriate sexualized behavior’
and ‘Personal Openness about intimacy’) had low internal
consistency. The scale ‘Amount of inappropriate sexualized
behavior’ measures behavior which is fairly uncommon and
thus has a low variance. This may have led to a low internal
consistency, which is in line with previous research (e.g.
Ginevra et al. 2015; Stokes and Kaur 2005). The other scale
(‘Personal openness about intimacy’) measures 1 concept,
but the questions cover different aspects of that concept
(i.e. feeling comfortable in discussion versus initiating
discussion versus discussion in different social groups), which
could have led to a lower internal consistency. Correlations
up im op
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S rom sex
showed that there are significant correlations between the
several domains of psychosexual functioning, underlining
the interrelatedness of its aspects. Often when discussing
sexuality, most attention is devoted to the domain of
sexual/intimate behavior. However, based on the correlation
analyses and previous studies, the domains of psychosexual
socialization and psychosexual selfhood are important
elements of psychosexual functioning, probably forming the
basis on which partnered sexualized/intimate behaviors
can be built. The significant correlations between
informants imply that at least to some extent informants agree,
although no result yielded a perfect correlation. Further
research on informant agreement is warranted.
ASD versus TD
The final aim of this study was to explore differences in
psychosexual functioning (i.e. psychosexual
socialization, psychosexual selfhood, and sexual/intimate behavior)
between adolescents with ASD and TD adolescents. We
found significant differences in all domains of
psychosexual functioning (i.e. psychosexual socialization,
psychosexual selfhood and sexual/intimate behavior) between
adolescents with ASD and TD adolescents. Our results showed
that in the domain of psychosexual socialization and
psychosexual selfhood differences were found both on
selfreport and parent-report, however in the domain of sexual/
intimate behavior, differences were only found when using
parent-report. This suggests that, particularly in the domain
of sexual/intimate behavior, the results of studies regarding
psychosexual functioning may depend on which
informant is chosen. Below we discuss our findings per domain
of psychosexual functioning in more detail in light of the
According to both parent- and self-report, adolescents with
ASD had significantly less friendship skills, and were
significantly less accepted by their peers than TD adolescents.
The reduced friendship skills and peer relations are in line
with previous research regarding social skills
et al. 2010)
, which indicated that having ASD is a unique
contributing factor to peer relationship problems.
Difficulties in this area may become increasingly problematic when
reaching adolescence (Murphy and Young 2005), as peer
relationships become increasingly important
and Harrison 2005)
(Laugeson et al. 2012)
The difficulties with intimacy as well as rejection by peers
which adolescents with ASD reported may lead to
loneliness, social anxiety and depression
(Eussen 2015; La Greca
and Harrison 2005)
as well as frustration
(Hellemans et al.
which have been related to problems such as anxiety
u is n
a l o
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is o o
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ly o i
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te t f
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tno /la tae ivoua tn -ap itrae liaze ivoua sex tiya ttie
lse ou xu tim ah lae ou ifn rpo xu ah lae ien tiv lae raa
ac m se in eb sc m o p se eb sc ln ca sc ep
S A A O S
and sexual delinquency
. In addition, due to
the problems with peers that the adolescents with ASD and
their parents reported, adolescents with ASD may be less
able, or less frequently in the position to learn from their
peers or other informal social sources
(Brown-Lavoie et al.
2014; Stokes et al. 2007; Sullivan and Caterino 2008)
in turn may lead to other problems in psychosexual
functioning, which is supported by the correlations we found
between the three domains of psychosexual functioning.
For example more peer problems is directly correlated with
more problems in social competence and romantic
confidence, which in turn are directly related to sexual/intimate
behavior. These results suggest that targeting more general
social skills could be a prerequisite for optimal
psychosexual functioning, and thus an improtant target when
providing psychosexual guidance or training.
According to parents, adolescents with ASD were also
poorer in adequately dealing with boundaries, of both
others and oneself. In TD adolescents, experimenting with
boundaries is a risk factor to become either the victim or a
perpetrator of inappropriate and unwanted sexual/intimate
(de Bruijn et al. 2006)
. Although several studies
have looked into inappropriate behaviors or victimization
of individuals with ASD, few have investigated the link of
being able to deal with boundaries to such behaviors and
experiences. In individuals with ASD, the problems with
boundaries may be less related to ‘typical’ experimentation
but rather a problem to recognize and respect boundaries.
The parents of adolescents with ASD reported similar
family openness about psychosexual topics compared to the
parents of TD adolescents. Similar to our results, Stokes
et al. (2007) found that in cognitively able individuals with
ASD (aged 13 to 36 years old) do not significantly differ in
learning about social or romantic relationships from their
parents in comparison to TD adolescents. Conversely, other
research found that parents of children with ASD reported
to not find the discussion of sexual or intimate topics
relevant, or to be apprehensive to communicate about sexuality
topics due to worries, e.g. fear that the child might develop
fixation on the topic
. However, the study of
was in a group of children with ASD, aged
between 6 and 13 years old, whereas our study involved
adolescents between the ages of 13 and 21. Potentially
when the children with ASD age into adolescence, the
parents become more comfortable discussing the topic of
sexuality and find it more appropriate. Also, our study took
place in a different country with probably different cultural
values regarding sexuality. The effect of parent–child
communication on risk behaviors in TD samples is mixed
Clark and Shields 1997; Somers and Paulson 2000)
indicating no relation with risk behaviors, and other research
indicating reduced or delayed sexual behavior, including
sexual risk behaviors
(Somers and Paulson 2000)
delinquency (Clark and Shields 1997). These differences in
findings of the effect of communication regarding
psychosexual topics may be related to the content discussed by the
various sources for example the expectations of the parents
(Holmes et al. 2015)
and/or the other learning opportunities
In our study, adolescents with ASD reported
similar personal openness about psychosexual topics as their
TD peers. However, in the previously described study of
Stokes et al. (2007) it was found that individuals with ASD
make significantly fewer use of their peers and friends for
information than their TD peers. Possibly due to problems
with peers, as found in several studies including our own,
adolescents with ASD may experience less opportunity to
learn from friends and peers
(Brown-Lavoie et al. 2014;
Stokes et al. 2007; Sullivan and Caterino 2008)
As parent and peer communication regarding sexuality
differs in terms of content and message
(Epstein and Ward
, different sources may also lead to different results
with regard to psychosexual functioning. As our results
show similar personal and family openness, but at the same
time also difficulties in the various domains of
psychosexual functioning, this may mean there is another
explanation. Possibly it is not the quantity but rather the content of
the communication which determines whether or not
difficulties in psychosexual functioning arise.
No significant differences were found with regard to
sexual preference. There is both research which supports this
as well as research which found significant
differences in sexual preference
(Byers et al. 2013)
. In the
study of Byers et al. (2013), adults were used as opposed
to adolescents, and participants were directly asked if they
identified with a specific sexual orientation. One potential
reason for the contradicting finding may be that we did not
directly ask the adolescents what their sexual preference
was, but rather asked if they had ever been in love with
a boy, and if they had ever been in love with a girl, and
afterwards based on the adolescents gender recoded this to
reflect hetero or homosexual love interests. Our method of
assessment of sexual preference reduces the difficulties that
individuals may have with the associations of the
predefined labels of sexual preference. Yet, we should also note
that differences in gender distributions across studies may
also explain differences in findings. In the current study,
only 14% of the ASD sample was female. Thus, more
research is needed to elucidate gender-specific differences
in psychosexual functioning in the context of ASD.
In addition, no significant differences were found with
regard to social, romantic and amount of sexual desires.
This is also in line with previous research
(Dewinter et al.
2014; Gilmour et al. 2012; Hénault 2006)
Parents reported a significant differences with regard
to the body image of their child, although the adolescents
themselves did not report this. Interestingly, little research
into body image in individuals with ASD has been
conducted. Often it is thought that individuals with ASD may
be less influenced by social conventions, as they may be
less sensitive to social disapproval
(e.g. Ray et al. 2004)
which would imply a body image less influenced by social
conventions. Potentially, the discrepancy in our study
between parent-report and self-report can be attributed to
this phenomena; the adolescents themselves are less
bothered by social conventions and thus report similar
satisfaction with their physical appearance as TD adolescents,
whereas parents may be more aware of the discrepancy of
the physical appearance of their child with the social
conventions, thus reporting a poorer body image. Contrary
to our study,
found that individuals with
Asperger syndrome reported a poor body image compared
to the general population, implying they are aware of their
looks and care about how they look. More research is
needed to clarify the body image of individuals with ASD.
Adolescents with ASD and their parents reported lower
perceived social competence. This is in line with previous
Williamson, Craig, and Slinger (2008
) as well
as the work of Stokes et al. (2007) who found low social
competence in adolescents with ASD. Higher perceived
social competence is in TD individuals related to spending
more time with someone of the other sex
(Zimmer-Gembeck and Gallaty 2006)
. Possibly the lower social
competence in adolescents with ASD may also influence the time
spend with peers of the other sex, thus limiting romantic
and sexual opportunities as well as learning opportunities.
Possibly, overall psychosexual functioning in adolescents
with ASD could be improved if support is targeted also at
the more general social skills.
Surprisingly, the two groups did not differ in their
romantic confidence. Some studies have underlined that
greater romantic confidence is expected in those with
greater social competence
(e.g. Giordano et al. 2006)
they may have more experience and thus more comfort
with navigating relationships (e.g. experience with making
up with a friend could improve confidence in romantic
relationships). More research is needed to investigate
romantic confidence in adolescents with ASD compared to TD
According to parent-report, adolescents with ASD had
significantly less psychosexual knowledge (e.g. regarding
reproductive health) than TD adolescents. Lack of
psychosexual knowledge has the risk of leading to inappropriate
(Collins et al. 2004)
. For example the
lack of insight in public or private behaviors
or being unable to identify abusive
(Sevlever et al. 2013)
. Specifically in individuals
with ASD the level of actual knowledge was found to be
a risk factor for sexual victimization
(Brown-Lavoie et al.
. Our correlations show a direct significant
relationship between psychosexual knowledge inappropriate
sexualized behavior and difficulties with adequately dealing
with boundaries in the ASD group. Although correlations
do not provide causal information, this may imply that the
improvement of knowledge could lead to improvements
in both dealing with boundaries and less inappropriate
behavior. One explanation for the limited psychosexual
knowledge in the adolescents with ASD may be their
particular learning skills; as implicit learning of social cues is
weakened in adolescents with ASD
(Hudson et al. 2012)
Therefore, adolescents with ASD often need to be
explicitly taught about psychosexual topics
Hatton and Tector 2010; Sullivan and Caterino 2008)
Furthermore, although currently a gradual shift in emphasis and
form of sex education at schools is taking place, often
sexual education still mainly focuses on the mechanical parts
of sexuality rather than the psychosexual aspects. This is
probably because in TD adolescents, much knowledge
on psychosexual topics is often learned naturally,
without explicit teaching, through peers
(Andrew et al. 2003;
Brown-Lavoie et al. 2014; Stokes et al. 2007)
. In addition,
informal non-social sources (e.g. media and internet) which
individuals with ASD use more often
(Brown-Lavoie et al.
, may provide an incorrect, overly romantic picture of
psychosexual functioning or distorted viewpoint through
pornography, which could lead to incorrect or limited
actual psychosexual knowledge. Therefore it would be
valuable to increase the psychosexual knowledge of
individuals with ASD, in an attempt to improve the other elements
of psychosexual functioning.
In this domain, parents reported significant differences,
while adolescents self-reports did not reveal such group
differences with regard to both appropriate sexual
behavior and inappropriate sexualized behavior. This finding
underlines the usefulness of using multiple informants with
regard to psychosexual functioning in individuals with
Parents of adolescents with ASD reported less sexual
behavior of their child than the parents of the TD
adolescents. The adolescents themselves did not report a
significant difference, although they report a similar trend.
Both parents and the adolescents indicate that
adolescents with ASD have shown approximately one-third of
the sexual behaviors and the TD adolescents about half of
the sexual behaviors. The non-significant difference found
in self-report is in line with other research using
selfreport, which has found that sexual behavior does not
differ between adolescents with ASD and those without ASD
(Dewinter et al. 2014)
. Research in adults using self-report
has found that particularly partnered behavior is less
common than solitary sexual behavior (i.e. masturbation) when
reporting about the last month
(Byers et al. 2013)
, but did
not compare this to TD adults. The fact that the adolescents
with ASD report slightly higher score on the scale of sexual
behaviors than their parents, may be because most sexual
behavior is displayed in private
(Dewinter et al. 2014)
and thus parents may be less aware. In addition, parents
of adolescents with ASD may assume that the behavior
is non-existent in line with the idea previously explained
that parents of individuals with ASD view their children
as a-sexual or the topic of sexuality not relevant
. At the same time, parents of TD adolescents may
assume their child does have the experience based on their
age rather than factual knowledge. Therefore particularly
when investigating psychosexual behavior it is essential to
use multiple informants, as different informants may lead to
different results and conclusions.
Parents also reported that adolescents with ASD
exhibited significantly more inappropriate sexualized behaviors
than their TD peers. However it must be noted that the scale
of ‘Inappropriate sexualized behavior’ had low internal
consistency, most likely due to the low rates of occurrence
of the inappropriate behaviors in our sample. Therefore,
the results should be interpreted in this light, showing that
many of the adolescents with ASD in our sample showed
very little to no inappropriate behavior, albeit
significantly more than TD adolescents. As has been underlined
by previous research, for example that of
, Ginevra et al. (2015), Hellemans et al. (2007),
and Stokes et al. (2007), a diverse range
of inappropriate behaviors (e.g. sexually provocative talk,
openly discussing sexuality, as well as public masturbation)
is reported in adolescents with ASD, regardless of
cognitive capacities. Many of these studies however reflect only
case-studies or small samples
(for a discussion see Kellaher
. Our study using a much larger sample of cognitively
able adolescents with ASD thus increases our
understanding that in fact inappropriate behavior is significantly more
likely to occur in individuals with ASD. Even if the
behaviors do not escalate to sexual offending, adolescents with
ASD who display inappropriate behaviors such as stalking,
are at risk for negative outcomes such as criminalization of
their behaviors (Stokes et al. 2007) regardless of the intent
of their behavior. The findings regarding inappropriate
behavior also underlines the importance of using multiple
When looking at stand-alone items, only parents
reported difficulties with intimacy with family members
and well-known acquaintances both in receiving and
initiating it. Such difficulties may complicate the development
of intimate and romantic relationships
(Tarnai and Wolfe
. Although the adolescents themselves do not report
these problems, intimacy problems with family may be
related to later intimacy problems. Again using multiple
informants is important to uncover a better insight in the
psychosexual functioning of adolescents with ASD.
Limitations and Methodological Considerations
Some caution is required when interpreting our results.
As the TTI is newly developed, more research should be
carried out to investigate the reliability and validity of the
inventory. Due to our sample size, we could not perform
(confirmatory) factor analyses for the scales as we were
underpowered (due to the ratio of items versus
participants). This means that the scales were developed based
on the literature and expert opinion, and we used
statistical analyses to check the Cronbach’s alpha of the scales,
which showed that most scales met the criteria for
internal consistency. However, some items did not correlate
in both samples above the 0.3 limit with the rest of the
items on the particular scale
, suggesting the
scales may be better if these items were removed. Studies
with larger samples are on their way to further investigate
which items should be removed from the scales. As the
TTI is a fairly long measure, it could benefit from item
reduction to improve its usability. One way to do this
would be to remove the opening questions on general
puberty issues and focus it to a psychosexual functioning
scale. Also, validation of the TTI against other
domainspecific measures is needed. A reliable and validated
inventory of psychosexual functioning may improve the
comparability and replicability of data and the research
performed into this topic. In addition, the results
represent a mostly cognitively able group of adolescents with
ASD, as the majority of our ASD sample had an IQ
within the normal range (scores between 85 and 115).
Potentially these cognitively able adolescents may be
more aware of their possible difficulties in psychosexual
functioning (e.g. social interaction), as particularly
cognitively able adolescents with ASD may be aware of their
shortcomings in comparison less cognitively able
adolescents with ASD
(e.g. Locke et al. 2010)
. Therefore our
results may be less applicable to adolescents whom are
less cognitively able. Although our pilot indicated that all
adolescents were able to read and answer the
questionnaire on their own, the reading level of the TTI should be
further investigated, especially, when considering using
it with less cognitively able participants. Moreover, in
the ASD sample, 14% (n = 11) was female, while in the
TD sample, this was 54% (n = 71). Although gender was
taken into consideration as a covariate in all analyses,
clearly, more research is needed to disentangle
important gender differences in psychosexual functioning in the
context of ASD. Lastly, besides the differences in
psychosexual functioning that we found between adolescents
with ASD and their TD peers, there were also several
0-findings (for example in the domain sexual/intimate
behavior: e.g. age of onset). However, as we used the
Bonferroni correction for multiple testing, which is rather
conservative and causes some loss of power (increasing
chances of Type II error)
, this may mean
that in fact some 0-findings are not 0-findings. Therefore,
we encourage future research to investigate psychosexual
functioning in larger samples to increase power to
examine the factor structure of the TTI and replicate our
positive as well as 0 findings.
Our study also has three notable strengths. First, we
attempted to develop a comprehensive measure including
all three domains of psychosexual functioning (i.e.
psychosexual socialization, psychosexual selfhood and sexual/
intimate behavior). By including all three domains in our
inventory we were able to get a more well-rounded view
of the level of psychosexual functioning of adolescents
with ASD, going beyond only information on a behavioral
level. This is particularly important as the interpersonal and
intrapersonal domains may form the basis of the behavioral
domain. Second, by including a TD comparison group and
their parents we were able to directly compare the groups
in their psychosexual functioning. Third, as we used both
parent-report and self-report we were able to get both
perspectives on several aspects of psychosexual functioning
of the adolescents. Our results showed that parents and the
adolescents themselves did not perceive their psychosexual
functioning completely the same, particularly in the domain
of sexual behavior (e.g. inappropriate sexualized behavior)
and in the domain psychosexual selfhood (i.e. body image).
Parents of adolescents with ASD reported significantly
more inappropriate sexualized behaviors and a more
negative body image than the parents of the TD adolescents,
while self-reports did not show significant differences.
There are several possible explanations for this difference
in parent and self-report: Possibly, parents pathologize
the behaviors of their children more, or the child has less
self-reflection decreasing the reliability of their self-report.
Although parent and self-report showed significant
correlations, more research is needed on informant-agreement.
Previous research should be considered in the light of
which informant was used, as results may differ depending
on the informant.
Overall Conclusions and Implications
Our findings reflect less favorable psychosexual
functioning in adolescents with ASD, although the TTI clearly
does require more rigorous investigation to both assess its
quality and in order to revise the instrument. As could be
expected, as social impairments are a hallmark of ASD,
adolescents with ASD showed less psychosexual
socialization (e.g. on social acceptance, friendship skills and
adequately dealing with boundaries) and poorer psychosexual
selfhood than their TD peers (i.e. less self-esteem, less
social competence and less psychosexual knowledge), both
on self-report and parent-report. In the domain of sexual/
intimate behavior only significant differences were found
on the parent-report, implying less typical and more
inappropriate sexualized behaviors as reported by the parents.
The interpersonal (socialization) and intrapersonal
(selfhood) domains, which significantly correlate with one
another, may form a basis for healthy overall psychosexual
functioning. Thus difficulties in these domains may
underlie difficulties in the behavioral domain. This could explain
why earlier studies focused primarily on problematic or
inappropriate behaviors, as these were most likely the most
pressing and problematic for the environment
Dewinter et al. 2013; Hellemans et al. 2007; Sevlever et al. 2013;
Stokes and Kaur 2005; t Hart-Kerkhoffs et al. 2009)
addition, informants differ in their report of psychosexual
functioning, implying the value of using multiple
informants. Future research into psychosexual functioning should
include multiple informants to aim to get the full picture as
well as investigate the factors which may be related to
discrepancies between informants.
Regardless of the exact interplay of the elements of
psychosexual functioning, the poorer psychosexual functioning
of adolescents with ASD may make them more vulnerable
also other domains. For example, the poorer psychosexual
socialization (e.g. the difficulties with peer relationships)
and psychosexual selfhood (e.g. limited self-esteem and
limited knowledge) may lead to frustration and loneliness;
possibly making adolescents with ASD more vulnerable
than their peers
(e.g. Brown-Lavoie et al. 2014; de Bruijn
et al. 2006; Vickerstaff et al. 2007)
training programs may decrease this vulnerability (Kirby et al.
2007) and improve psychosexual functioning, for
example by increasing psychosexual knowledge
(Dekker et al.
. Future research may provide more insight by
investigating the interplay between the different domains of
psychosexual functioning. This could perhaps shed more light
on the differences in psychosexual functioning between
individuals with ASD and TD individuals, for example the
sources and content of sexual education and their effect on
behavior or the effect of self-esteem on social relationships,
which potentially could lead to appropriate support in the
relevant areas. Also future research could look at how
problems in psychosexual functioning in individuals with ASD
potentially relates to other domains of their lives. If proper
support is provided to improve psychosexual functioning
hopefully this could lead to improvements in all aspects of
psychosexual functioning and potentially other domains to
which it is related.
Many of the psychosexual difficulties that
individuals with ASD show may also lead to more extreme
difficulties throughout their lives (i.e. sexual victimization or
(Dennison and Leclerc 2011; Geluk et al.
2012; Markham et al. 2010; Sevlever et al. 2013; Steiger
et al. 2014; Trzesniewski et al. 2006)
. However as the
concept is so interrelated investigating only one element may
be understating the intricate relations which all contribute
to healthy psychosexual functioning (Epstein and Ward
2008). Interventions aimed to improve psychosexual
functioning in adolescents with ASD may therefore not only
be important to improve psychosexual functioning, but
also to decrease the risk of the potential victimization and
Although more research is required to determine the
quality of the TTI, the differences we found between
adolescents with ASD and TD adolescents may support the
validity of the TTI as a tool when assessing psychosexual
functioning and identifying potential difficulties or
problem areas which may need more counseling or help when
working with adolescents with ASD. As the literature on
psychosexual functioning in adolescents with ASD is still
developing and steadily growing, we hope the present study
contributes to the understanding of psychosexual
functioning in adolescents with ASD and potential difficulties
they face. In turn this may contribute to research
regarding how to improve psychosexual functioning in
adolescents with ASD. Our results indicate that adolescents with
ASD have a less favorable psychosexual functioning than
TD adolescents in all domains (i.e. psychosexual
socialization, psychosexual selfhood and sexual/intimate behavior).
Future research could elaborate on our findings to
investigate which differences are most prudent to eliminate or
minimize and which depend mostly on the informant; to
decrease the risks adolescents with ASD have in
psychosexual functioning, both with regard to victimization as
well as sexual delinquency. Such insights may guide the
creation and adaptation of psychosexual training programs
aimed to improve psychosexual functioning.
Acknowledgments The authors thank the children and parents who
participated in this project. We thank the reviewers for their
constructive feedback that has helped us to improve the quality of this
manuscript. This research was supported by a grant from the Sophia
Foundation for Scientific Research (SSWO; Grant 617, 2010) and through
in kind contributions from the work package ‘Relations’ of the
Academic Workplace Autism Joint Effort!.
Author Contributions LPD was responsible for data collection,
data analysis, interpretation of the results, and drafted the
manuscript. EvdV, JvdE, NT, AL, AM and FCV participated in the design
of the study, the interpretation of the data and manuscript
development. KGL participated in the design of the study, data analysis,
interpretation of the results, manuscript development and supervised the
overall study. All authors read and approved the final version of the
Compliance with Ethical Standards
Conflict of interest Kirstin Greaves-Lord is second author on the
Dutch ADOS-2 manual, for which Yulius receives remuneration.
Frank Verhulst is head of the department of Child and Adolescent
Psychiatry at Erasmus MC, which publishes ASEBA materials and from
which he receives remuneration.
Ethical Statement At wave 1, parents of the participating children
signed informed consent forms prior to participation in the study. At
wave 2, both parents and adolescents signed the informed consent
forms. This study was approved by the local Medical Ethics
Open Access This article is distributed under the terms of the
Creative Commons Attribution 4.0 International License (http://
creativecommons.org/licenses/by/4.0/), which permits unrestricted
use, distribution, and reproduction in any medium, provided you give
appropriate credit to the original author(s) and the source, provide a
link to the Creative Commons license, and indicate if changes were
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