Towards a Treatment for Intolerance of Uncertainty for Autistic Adults: A Single Case Experimental Design Study
Journal of Autism and Developmental Disorders
Towards a Treatment for Intolerance of Uncertainty for Autistic Adults: A Single Case Experimental Design Study
J. Rodgers 0 1 2
R. Herrema 0 1 2
E. Honey 0 1 2
M. Freeston 0 1 2
0 Northumberland, Tyne and Wear NHS Foundation Trust , Newcastle upon Tyne , UK
1 School of Psychology, Faculty of Medical Sciences, Newcastle University , Newcastle , UK
2 Clinical Psychology, Faculty of Medical Sciences, Institute of Neuroscience, Sir James Spence Institute, Newcastle University, Royal Victoria Infirmary , Queen Victoria Road, Newcastle NE1 4LP , UK
Intolerance of uncertainty (IU) is indicated as an important transdiagnostic process variable in a range of anxiety disorders. Anxiety is very common in autistic adults. This study evaluates a manualised treatment programme for autistic adults, which focused on IU. An eight session programme (CUES-A©) was developed and delivered to four autistic adults on an individual basis. A single case experimental design was used to provide a preliminary evaluation of the feasibility, acceptability and preliminary effectiveness of the programme. Data regarding retention, acceptability and feasibility indicate that the participants valued the programme. Analyses of outcome measures indicate that the programme has promise as a treatment option for autistic adults experiencing IU.
Autism Spectrum Disorder; ASD; Adult; Anxiety; Intolerance of uncertainty; Intervention
Around 50% of autistic people experience levels of anxiety
that affect their everyday lives, highlighting the need for
(Davis et al. 2011; Sterling et al. 2008;
Mazefsky et al. 2008)
. Autistic individuals frequently
present with multiple anxiety disorders concurrently, therefore
treatments targeting underlying mechanisms may be most
efficacious. A recent evidence-based theoretical framework
to explain the mechanism that confers increased
vulnerability to anxiety and to inform treatment in ASD has been
proposed that includes intolerance of uncertainty as an
important transdiagnostic mechanism
(South and Rodgers 2017)
The intolerance of uncertainty model of anxiety
et al. 1998)
identifies IU as an assumption that uncertainty
is stressful and upsetting and not knowing what is going
to happen is negative and should be avoided at all costs.
IU is considered to be a ‘broad dispositional risk factor for
the development and maintenance of clinically significant
. It involves the ‘tendency to react
negatively on an emotional, cognitive, and behavioural level
to uncertain situations and events’ (Buhr and Dugas 2009).
Individuals who are intolerant of uncertainty find
uncertain situations stressful and upsetting; have a tendency to
interpret all ambiguous information as threatening and find
it difficult to function in the face of uncertainty
Dugas 2002, 2009; Laugesen et al. 2003)
uncertainty itself is perceived as threatening by people high in
. IU has been linked to the development
and maintenance of worry and Generalised Anxiety
(Buhr and Dugas 2006, 2009, 2012; Dugas et al.
1997, 2005; Freeston et al. 1994)
and has also been proposed
as a key underlying process in Obsessive Compulsive
(Holaway et al. 2006; Sookman and Pinard 2002;
Tolin et al. 2003)
. More recently, IU has been linked to other
disorders, including social anxiety disorder
Reijntjes 2009; Carleton et al. 2010)
, panic disorder (Boswell
et al. 2013) and anxiety sensitivity more generally
et al. 2007)
. IU is clearly important in the development and
maintenance of anxiety in the general population.
Recently, research has begun to investigate the
importance of IU to anxiety in Autism Spectrum Disorder (ASD).
The concept resonates clinically with some of the core
characteristics of ASD
(Joyce et al. 2017; Rodgers et al. 2012;
South and Rodgers 2017)
. Restricted and repetitive
behaviours, such as insistence on sameness, inflexible adherence
to routines and difficulty tolerating change have been linked
with anxiety since the earliest descriptions of the disorder
. These behaviours bear a conceptual
resemblance to IU, with its associated avoidance of unexpected
events and the desire to make life as predictable as possible
(Rodgers et al. 2012)
. Evidence is now emerging that IU has
a central role in the relationship between ASD and anxiety.
Boulter et al. (2014) modelled the relationship between
anxiety and IU in an ASD group and a neurotypical comparison
group. Results confirmed significant relationships between
IU and anxiety in autistic children and were consistent with
a causal model, suggesting that IU mediates the relationship
between ASD and anxiety. Wigham et al. (2015) examined
the role that IU has in pathways between sensory processing
difficulties, anxiety and restricted and repetitive behaviours
(RRB) in ASD. These relationships were mediated by IU,
indicating the important role IU may have in the interaction
between anxiety and ASD traits. This is further supported
Neil et al. (2016
) who reported that IU is an important
construct to explain the relationship between sensory
sensitivities and anxiety in autistic children. Chamberlain et al.
(2013) report associations between shared neurobehavioral
mechanisms in ASD and anxiety, indicating specific avenues
for intervention targeting IU, and
Maisel et al. (2016
illustrate the role that IU has in anxiety in autistic adults.
In terms of assessment, Rodgers et al. (2016b) developed
and validated a child self and parent report measure of
anxiety for autistic young people (the ASC-ASD). Using factor
analytic techniques, the study identified four valid anxiety
subscales, including an uncertainty scale.
) undertook focus groups with parents of autistic young
people exploring the concept of IU. Parents differentiated IU
from dislike of change and from fear, discussed examples of
IU and its impact on their children, and suggested that IU
is a recognisable and important construct associated with
anxiety that is distinguishable from but related to features of
Kerns et al. (2016
) in a discussion of the differential
diagnosis of anxiety disorders in autism report that fears
associated with uncertainty may be an important mechanism
in the development and maintenance of anxiety in ASD. In
conclusion, this evidence indicates that IU is an important
mechanism in the development and maintenance of anxiety
for autistic people and, as for neurotypical people
an appropriate target for intervention.
The concept of IU has utility not only to theoretically
inform understanding of factors underlying development
and maintenance of anxiety, but has also been shown to be
a beneficial target for treatment. Research has shown that
experimental manipulation of intolerance of uncertainty can
affect levels of worry in non-clinical neurotypical participants
(Ladouceur et al. 2000)
. Cognitive behavioural treatments for
clinically anxious patients have been developed which
emphasise treating the cognitive process rather than the cognitive
content of anxiety, specifically by aiming to increase patient’s
tolerance for uncertainty and thereby achieving more
(Wilkinson et al. 2011)
. Research has confirmed
the utility of such CBT protocols in reducing anxiety both in
(Dugas and Ladouceur 2000; Ladouceur et al. 2000)
and group formats
(Dugas et al. 2003)
. Case series have also
demonstrated the successful use of this intervention with
neurotypical children and adolescents
(Leger et al. 2003; Payne
et al. 2011)
A variety of cognitive behaviour therapy (CBT) based
programmes for anxiety and ASD have been evaluated recently,
mainly in children and adolescents
(Chalfant et al. 2007;
McConachie et al. 2014; White et al. 2009; Wood et al. 2009)
and with variable evidence for their effectiveness. These
intervention programmes using CBT approaches have been
variously adapted to meet the needs and learning styles of
people with ASD. However, the application of these techniques,
driven by the increasing awareness of the mental health needs
of this population, is in advance of clear understanding of the
underlying mechanisms inherent in anxiety in ASD. There
remains much still to be done to specify models of anxiety for
ASD populations, to enable the development of more targeted
and effective intervention programmes. Importantly, Keefer
et al. (2016) in a multisite manualised group intervention for
autistic children with high anxiety in the USA demonstrated
that high levels of pre-treatment IU significantly predicted
poorer treatment response.
A parent based group intervention (CUES©: Coping with
Uncertainty in Everyday Situations), aimed at providing
parents of autistic children with effective strategies to reduce
IU in their children in everyday situations has recently been
developed and the intervention is reported to be acceptable and
feasible to families
(Rodgers et al. 2016a)
. However, there is
a critical need to develop effective interventions specifically
for autistic adults.
The aim of this study therefore was to adapt and provide a
preliminary evaluation of the feasibility and acceptability of
an adapted version of the CUES© intervention programme,
aimed at reducing IU, to be delivered on an individual basis to
autistic adults (CUES-A©).
Autistic adults who had participated in focus groups (N = 12)
from a previous research study investigating concerns about
the future, were approached with information regarding this
study and invited to take part. Four participants responded.
Inclusion criteria was a clinical diagnosis of ASD, an adult
(18+ years) and a self-reported difficulty in managing
uncertainty. Exclusion criteria included the presence of a learning/
intellectual disability or presence of a complex or severe
mental health problem.
This research used a Single Case Experimental Design
(SCED), which allows monitoring of change within
participants and comparison between phases. Commensurate with
SCED the study was conducted over three phases; baseline
(A), intervention (B) and follow-up (C). Baseline length was
a minimum of 5 days to ensure sufficient data points and to
Social Responsiveness Questionnaire‑2A (SRS‑2A)
Participants completed the SRS-2A during the initial
meeting with the therapist. The SRS-2A
(Constantino and Gruber
is a standardised questionnaire used extensively to rate
the social communication difficulties of autistic adults. The
measure quantifies severity of autistic characteristics and
can be used to monitor symptoms throughout the life span
(Frazier et al. 2012)
. A Total Score in the range of 60–65
indicates an individual to be within “mild range” indicating
deficiencies which are clinically significant and may lead to
mild to moderate interference with everyday social
interactions. A total score within the range of 66–75 indicates an
individual to be within the “moderate range”, these scores
are typical for individuals with an ASD of moderate
severity. A total score of 76 or higher indicates an individual to
be within the “severe range” leading to severe and enduring
interference with everyday social interactions.
individualised self-monitoring of personally relevant anxiety
symptoms, target behaviours and engagement in target
uncertain situations. Participants completed a very brief daily diary
during all three phases: Baseline (Phase A—at least 5 days
prior to commencement of intervention), intervention (Phase
B—8 weeks) and follow-up (Phase C—at least 4 weeks after
completion of the intervention). The diary included brief
Likert scales delivered via a range of different methods, dependent
on participant preference (e.g. email, online survey,
spreadsheet or text message prompts), and took approximately 5 min
to complete. Questions were individualised for each
participant, who chose their own emotive anchor word (e.g. stressed,
anxious, frustrated) and their own scale (e.g. 1–5, 1–10). Some
scales were operationally defined for each individual by adding
anchor labels to enable further understanding and effective
use of the scale. An example of the template for the diaries is
Daily Diary Template
1. How anxious (emotion) do you feel about the target
situation (0–100% or scale)?
2. If you were to experience your target situation, how
anxious would this make you feel (0–100%)?
3. How confident do you feel about tackling your target
4. How well do you think you could handle your target
5. Has anxiety about your target situation stopped you from
doing anything today? Yes/No
a. If Yes, what have you avoided doing?
6. Did your target situation occur? Yes/No
a. If Yes, how well did you handle the situation?
7. How anxious have you felt generally today? (0–100%)
8. Have you used techniques discussed in sessions today?
a. If Yes, was this in relation to your target situation?
9. Has feeling anxious/uncertain stopped you from doing
anything today? Yes/No
Primary Outcome Measure: Target Situation Monitoring
a. If Yes, what did you avoid?
SCED approaches use repeated measures in each of the phases
to allow comparison across phases, usually comprising of daily
measurement using individualised diaries. In order to
measure the degree and process of change, participants undertook
The following measures were taken on three occasions; at
baseline, at the first session of the intervention and 4 weeks
after the end of the intervention.
Patient Health Questionnaire 9 (PHQ‑9)
(Martin et al. 2006)
is a 9-item depression
subscale from the Patient Health Questionnaire. It is used to
assist clinicians with screening for depression and
monitoring treatment response. The items of the PHQ-9 are based
directly on the nine diagnostic criteria for major depressive
disorder in the DSM-IV. The indicative clinical cut-off score
utilised was 9.
Generalized Anxiety Disorder 7 (GAD‑7)
(Spitzer et al. 2006)
is a 7-item self-reported
questionnaire for screening and severity measuring of
generalized anxiety disorder. The indicative clinical cut-off score
utilised was 10.
The PHQ-9 and GAD-7 are the most widely used
questionnaires in Primary Care Mental Health Services to assess
levels of low mood and anxiety.
Intolerance of Uncertainty Scale (IUS‑12)
IUS-12 is short 12-item scale questionnaire which screens
for anxious and avoidant components of IU
(Carleton et al.
. The 12 items are rated on a 5 point Likert scale
ranging from 1 (not at all characteristic of me) to 5 (entirely
characteristic of me) with a total score ranging from 12 to 60.
Based on data reported by Carleton et al. (2012), a score of
35 in adults is the point where the non-clinical and clinical
distributions intersect. The intersection conceptually
represents criterion “c” as defined by Jacobson and Truax (1991).
Therefore a score of > 35 may be a meaningful indicator of
“Significant IU” in adult samples.
Stress Scale from Depression, Anxiety and Stress Scale (DASS‑21)
(Lovibond and Lovibond 1995)
is a 21-item
scale which screens for depression, anxiety and stress. There
are seven items on each sub-category. Scores can range
from 0 to 42 for each sub-category. A higher score indicates
higher severity. The main use of the DASS is to assess the
degree or severity of an individual’s depression, anxiety
and stress. As the PHQ-9 and GAD-7 are already
measuring depression and anxiety, the stress scale was exclusively
used in order to solely measure stress levels for participants.
Crawford and Henry (2003)
report the reliability of the
DASS-21 to be excellent. There is no clinical cut off for the
stress subscale of the DASS.
The Adult Repetitive Behaviour Questionnaire‑2 (RBQ2A‑)
(Barrett et al. 2015)
has been adapted from
the Repetitive Behaviours Questionnaire-2, which was
designed for parents of young children to use. The RBQ2-A
is a 20-item questionnaire used in clinical practice to assess
the frequency of repetitive behaviours in autistic adults. The
items are rated on a 3 or 4 item scale. There is no clinical cut
off for the RBQ2-A.
Feasibility and Acceptability Interviews (Conducted in Phase C)
This phase occurred at least 4 weeks after the participant’s
final intervention session. Participants were asked to
complete primary outcome measures daily over the course of 1
week prior to their follow-up session and secondary outcome
measures on one occasion. Once participants completed the
intervention phase and all follow up measurements, they
were interviewed about their experiences of CUES-A©.
All participants followed the same procedure, although may
have progressed through sessions at a different rate.
Participants attended an initial session, followed by a minimum
of 5 days break (Phase A). Participants then commenced
eight or nine therapy sessions, depending on individual
need (Phase B). The sessions were designed to specifically
address a target uncertain situation identified by the
participant, which they found difficult to manage and caused
some degree of negative affect. Following the therapy
sessions, participants had at least a 4 week break followed by
a final follow-up session (Phase C). All sessions were audio
recorded for analysis.
Phase A included completion of baseline measures for each
participant. Participants met the therapist initially to discuss
individualisation of the primary outcome measure.
Participants then began daily target monitoring (primary outcome
measure). A minimum of 5 points per phase is considered
the standard in multiple baseline design
is extended on an individual basis if a baseline pattern is
unclear. Participant 1 had 6 days of baseline data points,
Participant 2 had 11 days of baseline data points,
Participant 3 had 12 baseline data points, and Participant 4 had 21
baseline data points.
Treatment‑Phase B—Delivery of CUESA‑© Programme
The treatment phase was the delivery of the manualised
intervention (CUES-A©) facilitated by a member of the
research team who is qualified in low intensity
psychological therapies (PGCert) and has experience of working with
autistic individuals. Based on the Coping with Uncertainty
in Everyday Situations programme (CUES©), Rodgers et al.
(2016a), eight to nine individual sessions were delivered to
each participant, lasting approximately 1 h each. Participants
completed the secondary outcome measures in their initial
intervention session and completed primary outcome
measures daily throughout this phase.
The content of the CUES-A© Programme includes:
familiarisation with the intolerance of uncertainty (IU) model of
anxiety, strategies for identifying anxious thoughts,
understanding the consequences of IU, the relationship between
IU and characteristics of autism, behavioural techniques to
increase tolerance of uncertainty, generalisation and
maintenance of strategies. Participants completed tasks outside the
sessions as agreed collaboratively within sessions. The
specific content of CUES-A© was adapted to the specific needs
of each individual, based on their particular presentation and
capabilities. The programme is designed to be flexible and
incorporate personal information that participants chose to
share. A bespoke range of strategies based on individual
presentations were discussed with participants. These
strategies are based on CBT techniques used in evidence-based
interventions but adapted for IU. All participants received
psycho-education on CBT and IU, as well as some
combination of cognitive re-structuring, mindfulness, behavioural
experiments and relapse prevention. The therapist received
regular supervision from a Clinical Psychologist to ensure
safe, effective and reflective practice. All sessions were
audio recorded for analysis, alongside written notes taken
during each session, including reflections. The therapist also
completed a fidelity to delivery checklist after each session
to ensure reliability of the delivery of each session.
The main components of the intervention are described
Initial Session During the initial session the therapist met
with the participants to discuss issues related to
confidentiality, consent and risk. Psychoeducation relating to
intolerance of uncertainty was provided and the participant and
therapist together identified a target uncertain situation that
would comprise the primary outcome measure, discussed
an agreed the format for the daily diary and completed the
secondary outcome measures.
Session 1: Topics covered during session one included
a further introduction to CUES-A© and Intolerance of
Uncertainty (IU); goal setting; psychoeducation relating to
Session 2: Session 2 incorporated a review of the previous
week and the use of the daily diary (also included in all
subsequent sessions); consideration of the relationship between IU
and autism; identification of barriers and less helpful
strategies; discussion of intervention choice.
Sessions 3–7: These sessions incorporated intervention
delivery based on the individuals presentation and could
include any combination of cognitive re-structuring,
behavioural experiments, mindfulness.
Session 8: This session focused on review, relapse
prevention and consolidation.
Participants were followed up at least 4 weeks after their final
session in Phase B. Participants were able to attend their
follow-up session either over the phone or during a face-to-face
appointment. Daily monitoring (primary outcome measures)
continued for a week following their final appointment in
Phase B and a week prior to their follow-up appointment with
a 2 week break with no contact in between. secondary outcome
measures were completed at the follow-up appointment.
Participants were then invited to participate in a semi-structured
interview about their experiences of the programme, allowing
for further exploration of their positive and negative feedback
regarding the programme and how effective they found it to
be. Figure 1 outlines the research procedure.
A favourable ethics opinion was provided by Newcastle
University, UK, Faculty of Medical Sciences Ethics Committee.
All participants provided informed, written consent.
Participants collaboratively completed a Normal Operating
Procedure template to ensure their safety regarding risk of harm to
self or others and included information regarding local
support services and emergency numbers. Risk was reviewed in
every session and any changes in risk level were addressed and
responded to accordingly. Risk was discussed during
supervision to ensure participant safety and to formulate risk
management plans where appropriate. Participants were also offered
thorough assistance in referring to psychological services if
required, to support their engagement and transition into
available support services. This was offered on an individual needs
basis for participants who had expressed additional difficulties,
which were not possible to address within the structure and
purpose of this intervention.
Attendance, Retention and Completion
Retention to the intervention was 100%, all participants
attended all scheduled sessions with short breaks for
holidays, illness or travel, and completed all outcome
Case Study Descriptions
Further detailed information can be found about each
participant and their tailored intervention below.
This participant has two autistic children and her
target uncertain situation related to their children’s social
interactions with others, which may lead to her having to
interact with others unexpectedly. This covered a variety
of settings, including school, hobbies, friend’s parents
and strangers. Participant 1 expressed that she is often
misunderstood or struggles in social situations and
therefore these situations can have an uncertain and potentially
Target situation: My children making me interact with
someone I don’t know.
Scale: Stress (0–10): Participant 1 chose to operationalise
each number on the scale in order to make it concrete and
meaningful to her.
Intervention treatment: A personalised strategy was
developed to challenge thoughts and put situations into
perspective. Participant 1 was encouraged to problem solve
whether situations need an immediate response on all
occasions or whether sometimes it is best to wait and re-evaluate.
She described how sometimes she made impulsive decisions
in order to create certainty.
A personalised alternative strategy was developed and
captured by the acronym DIRECT.
Danger, is my child in danger? If the answer is yes,
intervene to ensure their safety. If no, then continue with
Identify the issue, ask “what am I nervous about?”
identifying what is happening internally and externally.
Responsibility to react—ask “Do I need to intervene in
order to minimise distress to my children or others?” If
yes, intervene, if no, continue to monitor.
Explain “Actions”—ask “What would I say if someone
asked me why I’m not doing anything? How would I
explain my decisions/actions to someone else?”
Conscious of my stress—bring awareness and focus of
attention back on situation—back to what is happening
internally and externally.
Tension—dealing with tension, calming down and
focusing on breathing; ten mindful breaths.
This participant was in the process of setting up his own
business enterprise which will be a support service for
autistic adults; therefore this was a significant period of stress and
anxiety for him. He was having difficulty coping with the
elements of this process that were out of his direct control
and his target situation was therefore related to the impact
of other people’s decision making on him and inconsistent
Target situation: Other people making decisions that
might impact on me and also my business enterprise.
Scale: Frustration (0–4.5).
Not frustrated at all
“Couldn’t give a ****”—indifferent to situation
Frustrated enough to take impulsive action
Too frustrated to do anything—avoidant
Meltdown—completely incapable of coping
Intervention treatment: Mindfulness, Relaxation
strategies—progressive muscle relaxation, strategies to manage
IU—particularly when not in control of the uncertain
situation. These strategies were used in order to decrease initial
arousal level and prevent impulsive responding, allowing
him to “sit” with the uncertainty for some time. He used the
following acronym to approach the situation:
Pause—Don’t act straight away.
Acknowledge and assess.
Contemplation—Why is this affecting me? Think about
the situation as a whole.
Control—Can I do anything about it? Am I in control of
Change, accept or let go?
This participant had other difficulties relating to anxiety
and depression, self-esteem and self-worth. He was
therefore assisted in seeking some more general support from
a psychological service following his involvement in the
Target situation: Sudden or unexpected changes to
routine that cause anxiety, mainly but not exclusively relating
Scale: Anxiety (1–10) This client did not describe his
scale in as much detail as the other participants but explained
that a score of “10” would be considered worst case
scenario, when he would be experiencing sensory difficulties
and would most likely isolate himself.
Intervention treatment: Cognitive re-structuring and
mindfulness. Some examples from cognitive re-structuring
are shown below.
First example: at home, uncertainty about the impact of
being late for work, feeling anxious, negative thought: “I’m
going to be late for work at 9 a.m.”—what might happen if I
am late for work? People will think I’m not good at my job.
Evidence for: got up late.
Evidence against: Takes 20 min to get to work, alternative
thought “plenty of time to get to work and core hours don’t
start until 9.30 a.m.”
Second example: at home, uncertainty about whether an
external agency will automatically deduct money from bank
account, feeling anxious, negative thought: last year’s home
contents insurer automatically renewed my policy and tried
to take my money, will they pursue it? Evidence for: they
sent me an e-mail.
Evidence against: Distance selling regulations, alternative
thought: I’ll be able to cancel.
For this participant we encouraged lots of use of
questioning, recognising that it is helpful to ask “is this going to
impact negatively on me?” It was also recognised that it was
useful to encourage him to also ask; what do I already know
about this/what is my past experience of this? From looking
at the facts, what is the alternative? Am I over-thinking it?
Participant 3 found that by asking some of these questions,
he was able to re-frame his thoughts more realistically in
relation to uncertainty.
This participant had just begun university for the second
time. He had previously attempted university 14 years
previously aged 19 years. He had dropped out after 1 year and
one semester due to barriers he described as presented by
his autism diagnosis and lack of accessibility to appropriate
support from the university to manage this. The timing of
the CUES-A© programme came at a time of particularly
elevated anxiety as he began his university career once
again, and his social and environmental situation drastically
changed during the research intervention. He related that
the intervention had come at the best time in some ways as
he was going through such a big transition and changes in
his life, but that this also meant it was the worst time for the
intervention as he had to cope with so much change during
Target situation: Social interactions with others and
feeling unsure about the authenticity of other people’s reactions.
Scale: Anxiety (1–5) Participant 4 identified that he
would never score himself as a “0” or a “5”, he explained
that a “0” would be when he is on holiday and has no worries
at all for at least the week ahead. Whereas, “5” would be if
he was completely unable to cope or do anything about the
situation, a full “meltdown” leading to aggressive or
damaging behaviours, he would notice tension, feeling agitated,
noticing a feeling in his stomach, also having visual
problems and sensitivity to noise and light, and this would make
Intervention treatment: Identifying causes and
consequences of uncertain situations, evaluating rumination and
when to stop this evaluating whether it is helpful and
strategies to acceptance of uncertainty and mindfulness.
This participant created his own strategy:
1. Awareness: non-judgemental observation.
2. Label and Release: naming/acknowledging emotion.
3. Experience the moment/breathe.
In line with SCED design, results are presented in graphical
format based on questions from the daily diaries across all
phases, ordered from shortest to longest baseline lengths;
data from participants is presented in the same way in
Table 1. Graphs have been adapted so that all x axes show
the same information and all y axes show the scale
participants used within their daily diary. The variable depicted
in the graphs is confidence in managing their target
uncertain situation (Fig. 2). Given the early stage of the research
cycle and the aims of the study relating to feasibility and
acceptability we selected one primary outcome to report
here. Confidence in managing the target uncertain situation
was selected as our primary outcome measure because the
main goal of the programme is to promote the use of helpful
strategies to be able to more successfully manage uncertain
situations in the future. Given this aim assessing increased
confidence in managing uncertainty, especially in frequently
occurring situations in areas of occupational or family
functioning, is essential to a determination of the usefulness of
the intervention and indeed is likely a pre-requisite for the
additional outcomes such as perceptions of success in
managing uncertainty and changes in distress related to uncertain
situations. Visual data from the graph were rated by two
researchers (one independent of the study team) with 100%
Statistical Evaluation of Change
(Parker et al. 2011)
is an estimate of non-overlap
between phases; the greater the degree of non-overlap, the
greater the difference between the scores in each phase.
Tau-U can be corrected for baseline-trend. Tau-U is first
calculated for each participant and then an aggregate value
is calculated, weighted by the length of the series. Table 2
shows that two of the eight individual phase comparisons
(A vs. B and B vs. C) were significant. When data from all
participants were combined, significant increases in
confidence ratings from Phase A to Phase B and from Phase B to
Phase C can be seen (Table 2).
Table 3 shows the standardized outcome measures for each
participant, at Initial Session and Follow-Up session. The
“outcome” column indicates whether the Reliable Change
Index has been met and so that the difference in their scores
is “improved” as the scores have significantly decreased, or
“recovered” as the scores have significantly decreased and
moved from a clinical score to a sub-clinical score.
Feasibility and Acceptability Interviews
Data obtained from the Feasibility Interviews highlight a
number of themes derived using
Braun and Clarke’s (2006)
method of thematic analysis.
• The flexibility of CUES-A programme was helpful.
• The individualisation of the programme was helpful.
• The collaborative approach was important.
• The language used was important.
• It would be helpful to have this support as well as
additional practical support in relation to employment,
sensory difficulties etc.
Phase A versus B
Phase B versus C
When we first started using the STOPP technique, they
don’t go into whether you’re in danger and it didn’t
address this, so it didn’t take into account your
individual needs, which is why it was so good when we
individualised our own.
I think I am using the strategies sub-consciously but
generally feel a lot better when I’m having to deal with
I’ve come to realise I like uncertainty because it
I felt I was able to contribute to sessions but it didn’t
feel over-stated which is nice…it was good to have an
honest and rational approach to sessions.
It’s been very supportive, and very hands on when it
needs to be and very hands off when it needed to be. It
was a very relaxing experience and I felt very
comfortable and not judged at all.
I felt able to contribute to the sessions and I felt I could
discuss any difficulties and reflect on my week and I
felt able to say where the programme was going.
The biggest tool which wasn’t actually formalised and
was really helpful was the flexibility.
I don’t think I would have made the same progress if
this had been done in a group.
I would recommend the programme to someone else if
everything was changed in the sense that it was
completely individualised and flexible to them.
This project (CUES-A) has enabled me to cope with
things I wouldn’t have been able to previously.
There’s not so much of a flexible culture within IAPT/
NHS services as there can be within a research
programme. And those (mental health professionals) with
maybe not as much support or less experience of
people with autism, proper autism training with mental
healthcare professionals would be hugely invaluable.
The aim of this study was to adapt and provide preliminary
evaluation of the feasibility and acceptability of CUES-A©,
delivered on an individual basis to autistic adults. Given the
growing evidence base of the centrality of IU to anxiety
in autistic people
(Boulter et al. 2014; Chamberlain et al.
2013; Rodgers et al. 2016a, b; Keefer et al. 2016; Wigham
et al. 2015)
, coupled with the high prevalence of multiple
anxiety disorders occurring concurrently in ASD, targeting
important transdiagnostic mechanisms, such as IU, may have
significant treatment utility. The study builds on previous
work developing a parent mediated intervention for autistic
children with high IU
(Rodgers et al. 2016a)
. Using a
collaborative approach with four autistic adults, we co-constructed
and then delivered a manualised, eight session intervention
(CUES-A©). Utilising a single case experimental design
we collected individual data monitoring change within
participants and comparison between phases in relation to an
individualised target uncertain situation, alongside a number
of standardised measures. We also assessed feasibility and
acceptability of the programme by recording attendance and
completion, and through an end of programme evaluation
questionnaire and interview. Attendance and retention to the
programme was excellent. None of the participants dropped
out and all participants indicated that they would
recommend CUES-A to other autistic adults. Participants provided
a range of free text comments in relation to the programme
and a sample of these are provided here (the full data set
is available on request from the corresponding author). In
sum, these data indicate that the participants valued the
programme, recognised the role of IU in their lives and found
the strategies helpful.
Of course, given the stage of this work in the research
cycle, the primary focus was on feasibility and
acceptability. More formal evaluation of efficacy is a task for future
The data from the single case experimental design are
worthy of consideration here. All participants were able to
generate and operationalise a target uncertain situation that
they wished to address. Interestingly, for three of the
participants the target situation related directly to difficulties
which may be associated with an autism diagnosis,
including difficulties with social communication, theory of mind
and sudden changes to routine/plans, perhaps highlighting
the increased vulnerability to IU that may be present for
autistic individuals as a consequence of the interaction
between autistic traits and IU
(Wigham et al. 2015)
primary outcome variable was the participant’s confidence
in tackling their target uncertain situation. As can be seen
from Fig. 2, for three of the four participants confidence
generally increased over the course of the programme; this
was maintained at follow-up, despite increased exposure
to uncertainty as a consequence of engagement in
behavioural experiments in relation to uncertainty that are a
feature of participation in the programme. For Participant 4
the picture is not so clear cut. Figure 2 does not highlight
a clear confidence increase in tackling the target IU
situation for this individual; however, the CUES-A programme
came at a time of particularly elevated anxiety for this
participant, as he re-enrolled at university with all of the
social and environmental changes that that confers. He
related that the intervention had come at the best time in
some ways as he was going through such a big transition
and change in his life. As such, whilst we were not able
to detect significant changes in confidence in relation to
the IU target situation, Participant 4 reports that the
programme enabled him to cope with things he would not
previously have been able to manage. These conclusions
are further supported by the Tau-U Calculations reported
in Table 2. Tau-U was first calculated for each participant
and then an aggregate value was calculated, weighted by
the length of the series. Although only two of the eight
individual phase comparisons were significant
(Participants 2 and 4) perhaps due to low power, when all data
were combined, a significant increase in confidence
ratings from Phase A to Phase B and from Phase B to Phase
C was found.
We also collected data at three time points using a range
of standardised measures. Of course, with a sample of four
participants, group based quantitative analyses of these
data would not be meaningful. Rather we calculated
reliable and clinically significant change for each participant.
Two participants presented with scores on the PHQ-9,
which assesses depressive symptoms, indicating recovery
at follow-up (Participants 2 and 3). Participant 1 had low
scores at baseline on this measure (below clinical cut-off and
remained stable). Changes in self-reported anxiety and IU
scores are, of course, of particular interest given the target of
the CUES-A programme. Two participants showed change
on the anxiety measure the GAD-7. Participant 1 (who was
below clinical cut-off at baseline) showed improvement at
follow-up, and Participant 3 showed reliable and clinically
significant change and would be considered recovered at
follow-up. Three participants demonstrated change in
relation to the intolerance of uncertainty self-report measure
(IUS-12). Participants 1 and 2 were considered recovered,
whilst Participant 3, although still above clinical cut-off was
improved. Similarly, three participants demonstrated
significant improvement on the stress scale of the DASS-21. There
is an emerging literature and theoretical framework
suggesting a putative relationship between IU and restricted and
repetitive patterns of behaviour for autistic individuals, such
that engagement in repetitive acts may represent an attempt
to impose certainty in an uncertain world
(See South and
. Given this emergent work, we were
interested to determine whether participation in CUES-A may
impact on self-reported engagement in RRB amongst
autistic adults. To this end participants completed the RBQ2A.
Whilst there is no clinical cut-off for the RBQ2A, we can see
from Table 3 that all four participant’s scores on the
measure indicate reliable improvement (i.e. less engagement) in
repetitive behaviours at follow-up. To our knowledge this is
the first time that a reduction in core autism symptomatology
has been reported in relation to mental health intervention.
The lack of longer term follow-up is of course of note and
whilst beyond the scope and goals of the current project is
a major limitation of the current study. Of course, what is
needed to determine the effectiveness of CUES-A© is a fully
powered trial with long-term follow up of both proximal as
well as more distal outcomes (e.g. quality of life, social or
family functioning), in order to determine the clinical impact
of the programme. With this in mind it will be important for
future trials to think very carefully about the nature and
timing of outcome assessments, and to develop a valid
behavioural measure of IU to reduce the reliance on questionnaire
measures of IU.
In summary, the current study sought to take the first
steps towards the development of an intervention programme
for autistic adults, which focuses on an important
transdiagnostic construct underlying anxiety, intolerance of
uncertainty. This preliminary evaluation of the acceptability and
feasibility of the novel CUES-A© programme indicates
that the programme is feasible to deliver directly to autistic
adults, and is acceptable and face valid, and our
preliminary data indicate that CUES-A has promise as a method
to enable autistic adults to tackle the everyday challenges
conferred by high levels of intolerance of uncertainty.
Author Contributions JR and MF designed the study. All authors
contributed to the development of the intervention. EH provided clinical
supervision to the therapist (RH). JR, RH and MF analysed the data
and drafted the manuscript.
Funding The authors are grateful to the autistic people who
participated in this research. This work was generously supported by funding
from Research Autism.
Open Access This article is distributed under the terms of the
Creative Commons Attribution 4.0 International License (http://creativeco
mmons.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 made.
Barrett , S. L. , Uljarevic , M. , Baker , E. K. , Richdale , A. L. , Jones , C. R. G. , & Leekam , S. R. ( 2015 ). The adult repetitive behaviours questionnaire-2 (RBQ-2A): A self-report measure of restricted and repetitive behaviours . Journal of Autism and Developmental Disorders , 45 ( 11 ), 3680 - 3692 . https://doi.org/10.1007/s1080 3- 015 -2514-6.
Boelen , P. A. , & Reijntjes , A. ( 2009 ). Intolerance of uncertainty and social anxiety . Journal of Anxiety Disorders , 23 ( 1 ), 130 - 135 . https ://doi.org/10.1016/j.janxdis. 2008 . 04 .007.
Boswell , J. F. , Thompson-Hollands , J. , Farchione , T. J. , & Barlow , D. H. ( 2013 ). Intolerance of uncertainty: A common factor in the treatment of emotional disorders . Journal of Clinical Psychology , 69 ( 6 ), 630 - 645 . https://doi.org/10.1002/jclp.21965.
Boulter , C. , Freeston , M. , South , M. , & Rodgers , J. ( 2014 ). Intolerance of uncertainty as a framework for understanding anxiety in children and adolescents with autism spectrum disorders . Journal of Autism and Developmental Disorders , 44 ( 6 ), 1391 - 1402 . https ://doi.org/10.1007/s10803-013-2001-x.
Braun , V. , & Clarke , V. ( 2006 ). Using thematic analysis in psychology . Qualitative Research in Psychology, 3 ( 2 ), 77 - 101 .
Buhr , K. , & Dugas , M. J. ( 2002 ). The intolerance of uncertainty scale: Psychometric properties of the English version . Behaviour Research and Therapy , 40 ( 8 ), 931 - 945 .
Buhr , K. , & Dugas , M. J. ( 2006 ). Investigating the construct validity of intolerance of uncertainty and its unique relationship with worry . Journal of Anxiety Disorders , 20 ( 2 ), 222 - 236 . https:// doi.org/10.1016/j.janxdis. 2004 . 12 .004.
Buhr , K. , & Dugas , M. J. ( 2009 ). The role of fear of anxiety and intolerance of uncertainty in worry: An experimental manipulation . Behaviour Research and Therapy , 47 ( 3 ), 215 - 223 . https:// doi.org/10.1016/j.brat. 2008 . 12 .004.
Buhr , K. , & Dugas , M. J. ( 2012 ). Fear of emotions, experiential avoidance, and intolerance of uncertainty in worry and generalized anxiety disorder . International Journal of Cognitive Therapy , 5 ( 1 ), 1 - 17 .
Carleton , R. N. ( 2012 ). The intolerance of uncertainty construct in the context of anxiety disorders: Theoretical and practical perspectives . Expert Review of Neurotherapeutics , 12 ( 8 ), 937 - 947 . https://doi.org/10.1586/Ern.12.82.
Carleton , R. N. , Collimore , K. C. , & Asmundson , G. J. G. ( 2010 ). “It's not just the judgements-It's that I don't know”: Intolerance of uncertainty as a predictor of social anxiety . Journal of Anxiety Disorders , 24 ( 2 ), 189 - 195 . https://doi.org/10.1016/j.janxd is. 2009 . 10 .007.
Carleton , R. N. , Mulvogue , M. K. , Thibodeau , M. A. , McCabe , R. E. , Antony , M. M. , & Asmundson , G. J. G. ( 2012 ). Increasingly certain about uncertainty: Intolerance of uncertainty across anxiety and depression . Journal of Anxiety Disorders , 26 ( 3 ), 468 - 479 . https://doi.org/10.1016/j.janxdis. 2012 . 01 .011.
Carleton , R. N. , Norton , P. J. , & Asmundson , G. J. G. ( 2007 ). Fearing the unknown: A short version of the Intolerance of Uncertainty Scale . Journal of Anxiety Disorders , 21 ( 1 ), 105 - 117 . https:// doi.org/10.1016/j.janxdis. 2006 . 03 .014.
Carleton , R. N. , Sharpe , D. , & Asmundson , G. J. ( 2007 ). Anxiety sensitivity and intolerance of uncertainty: Requisites of the fundamental fears? Behaviour Research and Therapy, 45 ( 10 ), 2307 - 2316 . https://doi.org/10.1016/j.brat. 2007 . 04 .006.
Chalfant , A. M. , Rapee , R. , & Carroll , L. ( 2007 ). Treating anxiety disorders in children with high functioning autism spectrum disorders: A controlled trial . Journal of Autism and Developmental Disorders , 37 ( 10 ), 1842 - 1857 . https://doi.org/10.1007/ s10803-006-0318-4.
Chamberlain , P. D. , Rodgers , J. , Crowley , M. J. , White , S. E. , Freeston , M. H. , & South , M. ( 2013 ). A potentiated startle study of uncertainty and contextual anxiety in adolescents diagnosed with autism spectrum disorder . Molecular Autism , 4 , 31 .
Constantino , J. N. , & Gruber , C. P. ( 2012 ). Social Responsiveness Scale (SRS) . Torrance, CA: Western Psychological Services.
Crawford , J. R. , & Henry , J. D. ( 2003 ). The Depression Anxiety Stress Scales (DASS): Normative data and latent structure in a large non-clinical sample . British Journal of Clinical Psychology , 42 , 111 - 131 . doi:https://doi.org/10.1348/0144665033 21903544.
Davis , T. E. III, Hess , J. A. , Moree , B. N. , Fostad , J. C. , Dempsey , T. , Jenkins , W. S. , & Matson , J. L. ( 2011 ). Anxiety sympotms across the lifespan in people with autistic disorder . Research in Autism Spectrum Disorders , 5 , 112 - 118 .
Dugas , M. J. , Freeston , M. H. , & Ladouceur , R. ( 1997 ). Intolerance of uncertainty and problem orientation in worry . Cognitive Therapy and Research , 21 ( 6 ), 593 - 606 . https://doi.org/10.1023/A: 10218 90322153 .
Dugas , M. J. , Gagnon , F. , Ladouceur , R. , & Freeston , M. H. ( 1998 ). Generalized anxiety disorder: A preliminary test of a conceptual model . Behaviour Research and Therapy , 36 ( 2 ), 215 - 226 . https ://doi.org/10.1016/S0005- 7967 ( 97 ) 00070 - 3 .
Dugas , M. J. , & Ladouceur , R. ( 2000 ). Treatment of GAD-Targeting intolerance of uncertainty in two types of worry . Behavior Modification , 24 ( 5 ), 635 - 657 . https://doi.org/10.1177/01454 45500245002.
Dugas , M. J. , Ladouceur , R. , Leger , E. , Freeston , M. H. , Langlois , F. , Provencher , M. D. , & Boisvert , J. M. ( 2003 ). Group cognitive-behavioral therapy for generalized anxiety disorder: Treatment outcome and long-term follow-up . Journal of Consulting and Clinical Psychology , 71 ( 4 ), 821 - 825 . https://doi. org/10.1037/ 0022 - 006x . 71 .4.821.
Dugas , M. J. , Marchand , A. , & Ladouceur , R. ( 2005 ). Further validation of a cognitive-behavioral model of generalized anxiety disorder: Diagnostic and symptom specificity . Journal of Anxiety Disorders , 19 ( 3 ), 329 - 343 . https://doi.org/10.1016/j.janxd is. 2004 . 02 .002.
Einstein , D. A. ( 2014 ). Extension of the transdiagnostic model to focus on intolerance of uncertainty: A review of the literature and implications for treatment . Clinical Psychology: Science and Practice , 21 ( 3 ), 280 - 300 . https://doi.org/10.1111/ cpsp.12077.
Frazier , T. W. , Youngstrom , E. A. , Speer , L. , Embacher , R. , Law , P. , Constantino , J. , … Eng , C. ( 2012 ). Validation of proposed DSM-5 criteria for autism spectrum disorder . Journal of the American Academy of Child and Adolescent Psychiatry , 51 ( 1 ), 28 - 40 . https ://doi.org/10.1016/j.jaac. 2011 . 09 .021.
Freeston , M. H. , Rheaume , J. , Letarte , H. , Dugas , M. J. , & Ladouceur , R. ( 1994 ). Why do people worry? Personality and Individual Differences , 17 ( 6 ), 791 - 802 . https://doi.org/10.1016/ 0191 - 8869 ( 94 ) 90048 - 5 .
Hodgson , A. R. , Freeston , M. H. , Honey , E. , & Rodgers , J. ( 2017 ). Facing the unknown: Intolerance of uncertainty in children with autism spectrum disorder . Journal of Applied Research in Intellectual Disabilities , 30 ( 2 ), 336 - 344 . https://doi.org/10.1111/ jar.12245.
Holaway , R. M. , Heimberg , R. G. , & Coles , M. E. ( 2006 ). A comparison of intolerance of uncertainty in analogue obsessive compulsive disorder and generalized anxiety disorder . Journal of Anxiety Disorders , 20 ( 2 ), 158 - 174 . https://doi.org/10.1016/j.janxd is. 2005 . 01 .002.
Jacobson , N. S. , & Truax , P. ( 1991 ). Clinical significance-A statistical approach to defining meaningful change in psychotherapy research . Journal of Consulting and Clinical Psychology , 59 ( 1 ), 12 - 19 . doi:https://doi.org/10.1037//0022- 006x . 59 .1.12.
Joyce , C. , Honey , E. , Leekam , S. R. , Barrett , S. L. , & Rodgers , J. ( 2017 ). Anxiety, intolerance of uncertainty and restricted and repetitive behaviour: Insights directly from young people with ASD . Journal of Autism and Developmental Disorders , 47 ( 12 ), 3789 - 3802 (Epub ahead of print).
Kanner , L. ( 1943 ). Autistic disturbances of affective contact . Nervous Child , 2 , 217 - 250 .
Keefer , A. , Kreiser , N. L. , Singh , V. , Blakeley-Smith , A. , Duncan , A. , Johnson , C. , … Vasa, R. A. ( 2016 ). Intolerance of uncertainty predicts anxiety outcomes following CBT in youth with ASD . Journal of Autism and Developmental Disorders . https://doi. org/10.1007/s10803-016-2852-z.
Kerns , C. M. , Rump , K. , Worley , J. , Kratz , H. , McVey , A. , Herrington , J. , & Miller , J. ( 2016 ). The differential diagnosis of anxiety disorders in cognitively-able youth with autism . Cognitive and Behavioral Practice , 23 ( 4 ), 530 - 547 .
Ladouceur , R. , Dugas , M. J. , Freeston , M. H. , Leger , E. , Gagnon , F. , & Thibodeau , N. ( 2000 ). Efficacy of a cognitive-behavioral treatment for generalized anxiety disorder: Evaluation in a controlled clinical trial . Journal of Consulting and Clinical Psychology , 68 ( 6 ), 957 - 964 . https://doi.org/10.1037/ 0022 - 006x . 68 .6.957.
Ladouceur , R. , Gosselin , P. , & Dugas , M. J. ( 2000 ). Experimental manipulation of intolerance of uncertainty: A study of a theoretical model of worry . Behaviour Research and Therapy , 38 ( 9 ), 933 - 941 . https://doi.org/10.1016/S0005- 7967 ( 99 ) 00133 - 3 .
Laugesen , N. , Dugas , M. J. , & Bukowski , W. M. ( 2003 ). Understanding adolescent worry: The application of a cognitive model . Journal of Abnormal Child Psychology , 31 ( 1 ), 55 - 64 . https://doi. org/10.1023/A: 1021721332181 .
Leger , E. , Ladouceur , R. , Dugas , M. J. , & Freeston , M. H. ( 2003 ). Cognitive-behavioral treatment of generalized anxiety disorder among adolescents: A case series . Journal of the American Academy of Child and Adolescent Psychiatry , 42 ( 3 ), 327 - 330 . https:// doi.org/10.1097/01.Chi. 0000037034 .04952.B1.
Lovibond , S. H. , & Lovibond , P. F. ( 1995 ). Manual for the Depression Anxiety Stress Scales . Sydney: Psychology Foundation.
Maisel , M. E. , Stephenson , K. G. , South , M. , Rogers , J. , Freeston , M. H. , & Gaigg , S. B. ( 2016 ). Modeling the cognitive mechanisms linking autistic symptoms and anxiety in adults . Journal of Abnormal Psychology , 125 ( 5 ), 692 - 703 .
Martin , A. , Rief , W. , Klaiberg , A. , & Braehler , E. ( 2006 ). Validity of the Brief Patient Health Questionnaire Mood Scale (PHQ-9) in the general population . General Hospital Psychiatry , 28 ( 1 ), 71 - 77 . https://doi.org/10.1016/j.genhosppsych. 2005 . 07 .003.
Mazefsky , C. , Williams , D. , & Minshew , N. ( 2008 ). Variability in adaptive behaviour in autism: Evidence for the importance of family history . Journal of Abnormal Child Psychology , 36 ( 4 ), 591 - 599 .
McConachie , H. , McLaughlin , E. , Grahame , V. , Taylor , H., Honey , E. , Tavernor , L. , … Le Couteur, A. ( 2014 ). Group therapy for anxiety in children with autism spectrum disorder . Autism , 18 ( 6 ), 723 - 732 . https://doi.org/10.1177/1362361313488839.
Neil , L. , Olsson , N. C. , & Pellicano , E. ( 2016 ). The relationship between intolerance of uncertainty, sensory sensitivities and anxiety in autistic and typically developing children . Journal of Autism and Developmental Disorders , 46 ( 6 ), 1962 - 1973 . https:// doi.org/10.1007/s10803-016-2721-9.
Parker , R. I. , Vannest , K. J. , Davis , J. L. , & Sauber , S. B. ( 2011 ). Combining non-overlap and trend for single-case research: TauU . Behavior Therapy, 42 ( 2 ), 284 - 299 . https://doi.org/10.1016/j. beth. 2010 . 08 .006.
Payne , S. , Bolton , D. , & Perrin , S. ( 2011 ). A pilot investigation of cognitive therapy for generalized anxiety disorder in children aged 7-17 Years . Cognitive Therapy and Research , 35 ( 2 ), 171 - 178 . https://doi.org/10.1007/s10608-010-9341-z.
Rodgers , J. , Glod , M. , Connolly , B. , & McConachie , H. ( 2012 ). The relationship between anxiety and repetitive behaviours in autism spectrum disorder . Journal of Autism and Developmental Disorders , 42 ( 11 ), 2404 - 2409 . https://doi.org/10.1007/s1080 3- 012 -1531-y.
Rodgers , J. , Hodgson , A. , Shields , K. , Wright , C. , Honey , E. , & Freeston , M. ( 2016a ). Towards a treatment for intolerance of uncertainty in young people with autism spectrum disorder: Development of the coping with uncertainty in everyday situations (CUES©) Programme . Journal of Autism and Developmental Disorders . https://doi.org/10.1007/s10803-016-2924-0.
Rodgers , J. , Wigham , S. , McConachie , H. , Freeston , M. , Honey , E. , & Parr , J. R. ( 2016b ). Development of the anxiety scale for children with autism spectrum disorder (ASC-ASD) . Autism Research , 9 ( 11 ), 1205 - 1215 . https://doi.org/10.1002/aur.1603.
Smith , J. D. ( 2012 ). Single-case experimental designs: A systematic review of published research and current standards . Psychological Methods , 17 ( 4 ), 510 - 550 . https://doi.org/10.1037/a0029312.
Sookman , D. , & Pinard , G. ( 2002 ). Overestimation of threat and intolerance of uncertainty in obsessive compulsive disorder . In Frost, R. O. & Steketee , G . (Eds.), Cognitive approaches to obsessions and compulsions-Theory, assessment, and treatment . Oxford: Elsevier.
South , M. , & Rodgers , J. ( 2017 ). Sensory, emotional and cognitive contributions to anxiety in autism spectrum disorders . Frontiers in Human Neuroscience , 11 , 20 .
Spitzer , R. L. , Kroenke , K. , Williams , J. B. W. , & Lowe , B. ( 2006 ). A brief measure for assessing generalized anxiety disorder-The GAD-7 . Archives of Internal Medicine, 166 ( 10 ), 1092 - 1097 .
Sterling , L. , Dawson , G. , Estes , A. , & Greenson , J. ( 2008 ). Characteristics associated with presence of depressive symptoms in adults with autism spectrum disorder . Journal of Autism and Developmental Disorders , 38 , 1011 - 1018 . https://doi.org/10.1007/s1080 3- 007 -0477-y.
Tolin , D. F. , Abramowitz , J. S. , Brigidi , B. D. , & Foa , E. B. ( 2003 ). Intolerance of uncertainty in obsessive-compulsive disorder . Journal of Anxiety Disorders , 17 ( 2 ), 233 - 242 .
White , S. W. , Ollendick , T. , Scahill , L. , Oswald , D. , & Albano , A. M. ( 2009 ). Preliminary efficacy of a cognitive-behavioral treatment program for anxious youth with autism spectrum disorders . Journal of Autism and Developmental Disorders , 39 ( 12 ), 1652 - 1662 . https://doi.org/10.1007/s10803-009-0801-9.
Wigham , S. , Rodgers , J. , South , M. , McConachie , H. , & Freeston , M. ( 2015 ). The interplay between sensory processing abnormalities, intolerance of uncertainty, anxiety and restricted and repetitive behaviours in autism spectrum disorder . Journal of Autism and Developmental Disorders , 45 ( 4 ), 943 - 952 . https:// doi.org/10.1007/s10803-014-2248-x.
Wilkinson , A. , Meares , K. , & Freeston , M. ( 2011 ). CBT for worry and generalised anxiety disorder . London: Sage
Wood , J. J. , Drahota , A. , Sze , K. , Har , K. , Chiu , A. , & Langer , D. A. ( 2009 ). Cognitive behavioral therapy for anxiety in children with autism spectrum disorders: A randomized, controlled trial . Journal of Child Psychology and Psychiatry , 50 ( 3 ), 224 - 234 . https:// doi.org/10.1111/j.1469- 7610 . 2008 . 01948 .x.