Group schema therapy versus group cognitive behavioral therapy for social anxiety disorder with comorbid avoidant personality disorder: study protocol for a randomized controlled trial
Baljé et al. Trials
Group schema therapy versus group cognitive behavioral therapy for social anxiety disorder with comorbid avoidant personality disorder: study protocol for a randomized controlled trial
Astrid Baljé 0
Anja Greeven 0 2
Anne van Giezen 0 2
Kees Korrelboom 0 3
Arnoud Arntz 1
Philip Spinhoven 0 2
0 Department of Anxiety, PsyQ , Lijnbaan 4, 2512 VA The Hague , The Netherlands
1 Department of Clinical Psychology, University of Amsterdam , PO Box 159331001 NK Amsterdam , The Netherlands
2 Institute of Psychology, Section of Clinical Psychology, Leiden University , Wassenaarseweg 52, 2333 AK Leiden , The Netherlands
3 Department of Medical and Clinical Psychology Tilburg University , PO Box 901535000 LE Tilburg , The Netherlands
Background: Social anxiety disorder (SAD) with comorbid avoidant personality disorder (APD) has a high prevalence and is associated with serious psychosocial problems and high societal costs. When patients suffer from both SAD and APD, the Dutch multidisciplinary guidelines for personality disorders advise offering prolonged cognitive behavioral therapy (CBT). Recently there is increasing evidence for the effectiveness of schema therapy (ST) for personality disorders such as borderline personality disorder and cluster C personality disorders. Since ST addresses underlying personality characteristics and maladaptive coping strategies developed in childhood, this treatment might be particularly effective for patients with SAD and comorbid APD. To our knowledge, there are no studies comparing CBT with ST in this particular group of patients. This superiority trial aims at comparing the effectiveness of these treatments. As an additional goal, predictors and underlying mechanisms of change will be explored. Methods/design: The design of the study is a multicentre two-group randomized controlled trial (RCT) in which the treatment effect of group cognitive behavioral therapy (GCBT) will be compared to that of group schema therapy (GST) in a semi-open group format. A total of 128 patients aged 18-65 years old will be enrolled. Patients will receive 30 sessions of GCBT or GST during a period of approximately 9 months. Primary outcome measures are the Liebowitz Social Anxiety Scale Self-Report (LSAS-SR) for social anxiety disorder and the newly developed Avoidant Personality Disorder Severity Index (AVPDSI) for avoidant personality disorder. Secondary outcome measures are the MINI section SAD, the SCID-II section APD, the Schema Mode Inventory (SMI-2), the Inventory of Depressive Symptomatology SelfReport (IDS-SR), the World Health Organization Quality of Life-BREF (WHOQOL-BREF), the Difficulties in Emotion Regulation Scale (DERS), the Rosenberg Self-Esteem Scale (RSES) and the Acceptance and Action Questionnaire (AAQII). Data will be collected at the start, halfway and at the end of the treatment, followed by measurements at 3, 6 and 12 months post-treatment. Discussion: The trial will increase our knowledge on the effectiveness and applicability of both treatment modalities for patients suffering from both diagnoses.
Social anxiety disorder; Randomized controlled trial; Group schema therapy; Group cognitive behavioral therapy; Avoidant personality disorder
Beginning with the Diagnostic and Statistical Manual of
Mental Disorders (DSM)-III  and continuing in DSM-IV
, individuals whose fears are manifest in most social
situations are assigned to the generalized subtype of social
anxiety disorder (SAD), while individuals whose fears are more
circumscribed are grouped together as a separate category,
referred to as non-generalized social anxiety disorder. Since
the introduction of the generalized subtype, there is a
controversy about the differences with avoidant personality
disorder (APD) . While some researchers emphasize that
APD is a serious form of generalized SAD [4, 5], a growing
number of studies indicate that there is a qualitative
difference between the two disorders. Shortcomings in
establishing interpersonal relationships and severe feelings of
inferiority are seen as cardinal features of APD [3, 6, 7].
To preserve continuity with clinical practice, the
categorical diagnoses and criteria for personality disorders in
the DSM-5 are kept the same. An alternative dimensional
model is added in which, besides limitations in
(inter)personal functioning, specific maladaptive traits pertaining to
the dimensions of ‘detachment’ and ‘negative affectivity’
characterize persons with APD. Detachment is reflected in
maladaptive traits such as withdrawal, anhedonia and
intimacy avoidance, while anxiousness and worry in relation
to social situations characterize these patients with respect
to negative affectivity . Furthermore, on the basis of
empirical findings, it has been suggested that avoidance is
a dominant coping strategy not only in social but also in
non-social situations in APD [9–11].
APD is associated with high societal costs due to frequent
use of somatic and mental health care, a high risk for
developing other mental disorders and suboptimal professional
functioning. Furthermore, patients report a low quality of
life, and for family members, having a relative with a
diagnosis of APD is often a considerable burden .
In clinical practice, there is no consensus about which
treatment is indicated for patients with diagnoses of
both SAD and APD. In the Netherlands the
multidisciplinary guidelines recommend offering prolonged
cognitive behavioral therapy (CBT) in the case of SAD with
comorbid APD .
A small number of effectiveness studies have shown
that CBT and pharmacological interventions are effective
for patients with SAD and comorbid APD [14, 15].
Research among a sample of patients with social anxiety
and patients with social anxiety and comorbid APD
showed that APD was not predictive of CBT treatment
outcome, and that several subjects who received a
diagnosis of APD before treatment no longer met criteria for
APD after treatment . CBT in group format is
approximately as effective as individual CBT .
Furthermore, there is growing evidence that schema
therapy (ST) is an effective treatment for patients with APD
[18, 19]. Research has shown that APD is associated with
emotional neglect and abuse in the past [20, 21]. When the
normal, healthy developmental needs of childhood are not
met, maladaptive schemas develop. Activation of these
schemas can trigger an emotional, cognitive and behavioral
state, which in ST is called a ‘schema mode’ . APD can
be well conceptualized in terms of schema modes, with
detached and avoidant protector modes as prominent coping
modes, lonely child and abandoned/abused child mode as
prominent child modes and punitive parent mode as
prominent internalized parent mode [10, 23]. Within ST
different techniques are applied, including experiential
techniques such as imagery rescripting and mode
roleplays, that explicitly address dysfunctional coping modes. A
new development is group ST (GST), where specific
methods and techniques are applied to use the group
process in order to facilitate the process of change [22, 24].
Because of the promising results of ST, we designed a
superiority trial with the primary objective of investigating
the effectiveness of group schema therapy (GST)
compared to prolonged group CBT (GCBT) for patients with
social anxiety disorder (SAD) and comorbid avoidant
personality disorder (APD). More specifically the following
research question has been formulated: What is the effect
of prolonged GCBT compared with GST for SAD with
APD? Since people included in this trial will be diagnosed
with both SAD and APD, improvements can be realized
in two different domains: with respect to SAD symptoms
and with respect to severity of APD traits. Therefore, the
research question can be more explicitly formulated in the
following questions: How do the effects of prolonged
GCBT and GST compare for social anxiety disorder? and
How do the effects of prolonged GCBT and GST compare
for avoidant personality disorder?
Investigating predictors, moderators and mediators of
treatment can add valuable knowledge to our
understanding of for whom, under what conditions and how
treatments work, thus generating valuable hypotheses for future
research . Therefore, this study will, as a secondary
objective, look at possible predictors, moderators and
mediators of changes on the primary outcome measures. As
putative mediators, emotion regulation, self-esteem and
schema mode manifestations will be repeatedly measured
and associated with outcome. To detect possible predictors
and moderators of treatment, the (differential) predictive
value of different baseline measures for changes on the
primary outcome measures will be explored.
The design of the study will be a 30-session (on a weekly
basis), two-group (GST, GCBT) randomized controlled
clinical trial with repeated measurements at baseline (T0),
mid-test (T1), post-test (T2) and at 3 months follow-up
(T3), half-year follow-up (T4) and 1-year follow-up (T5).
Assessment will include diagnostic interviews, symptom
questionnaires and quality of life, self-esteem,
schemarelated and emotion regulation measures. See Fig. 1 (Flow
chart of enrolment, intervention and assessments) and
Additional file 1 (Standard Protocol Items:
Recommendations for Interventional Trials (SPIRIT) flow diagram) for
an overview of the study; the SPIRIT checklist is presented
in Additional file 2. Diagnostic interviews are based on the
DSM-IV classification system , since the DSM-5  was
not yet available during the developmental phase of this
study and there was an absence of diagnostic instruments
based on the DSM-5 at the start of the study.
After conclusion of the experimental part of the study
(3 months after the last session of the treatment),
patients will enter a naturalistic follow-up period in which
they are allowed to seek help the way they would
normally do when they feel in need for further treatment.
The study will be performed at two sites of PsyQ, a large
ambulatory mental health organization in the Netherlands.
Two departments of anxiety disorders of PsyQ will
Fig. 1 Flow chart of enrolment, intervention and assessments
participate, one located in The Hague and the other in
Rotterdam. Other departments, for instance, the departments
of depression or personality disorders, in the regions of The
Hague and Rotterdam will be informed of the study and
will be asked to refer eligible patients. If necessary to
guarantee a sufficient inclusion of eligible patients, more
treatment centres will be approached for study participation.
Before the start of the randomized controlled trial
(RCT), a chart review showed that both the PsyQ
location of Rotterdam and the PsyQ location of The Hague
have an annual patient flow of 40 patients with both
SAD as well as a comorbid APD. This represents an
overall yearly N of 80, of which it is expected that
approximately 90 % (N = 72) will be included. This means
that every year in each department 36 patients can be
randomized over the two conditions. CBT and ST groups
consist of a maximum of 9 patients.
We know that CBT has a large effect on SAD compared
to waitlist and a small to moderate effect compared to
placebo . With respect to ST, in a randomized trial
comparing ST, clarification therapy and treatment as usual
(TAU), Bamelis et al.  found an odds ratio between ST
and TAU in recovery from PD diagnosis in the 3–4 range
(depending on the specific (sensitivity) analysis), which is
equivalent to Cohen’s d = .60–.76 . Though a
substantial number of patients in the ST condition had a diagnosis
of APD, only a small minority of patients received CBT as
TAU. No studies are available directly comparing ST with
CBT with respect to APD with comorbid SAD. We
therefore designed our RCT as a superiority trial with enough
statistical power to detect a difference in outcome
between treatments (if present) with a medium effect size
(Cohen’s d = .5). We chose this minimum difference
because such a difference is important based on a patient’s
perspective or clinical knowledge. Expecting larger
differences in outcome does not seem realistic and might result
in an underpowered study, while detecting smaller
differences is of less relevance for clinical practice. Thus, we
designed our study to detect a medium effect size (0.50)
with a power of 80 % and a two-tailed alpha set at 0.05 on
the primary outcome measures, severity of social anxiety
(Liebowitz Social Anxiety Scale Self-Report, LSAS-SR)
and severity of avoidant personality disorder (Avoidant
Personality Disorder Severity Index, AVPDSI). This
implies that 64 patients per study group and in total 128
patients are needed for the present project.
Inclusion and exclusion criteria
Patients aged between 18 and 65 with primary diagnoses of
SAD on Axis I and comorbid APD on Axis II will be
included in the study. Primary diagnosis is defined as the
diagnosis on which treatment should focus at first instance
according to both patient and clinical staff. Other inclusion
criteria are willingness, motivation and practical ability to
attend 30 sessions of group therapy and to refrain from
treatment or counselling outside the context of the present
trial. The use of antidepressant medication or
benzodiazepine will be permitted, under the condition that the
medication dose has been stable for at least 3 months before
inclusion and patients are willing not to raise the dosage of
the medication during the active phase of the trial.
Furthermore, patients must be willing to complete homework
assignments between sessions and must sign written
informed consent to participate in the study.
Exclusion criteria are suicidality and the presence of
psychotic or bipolar symptoms, because these conditions
could interfere with the measurement and treatment
procedures and suggest an immediate need for alternative
interventions. Another exclusion criterion is an Axis I
diagnosis of substance abuse or dependence which needs,
according to the clinical staff, detoxification (after
successful detoxification patients can participate). Moreover,
patients with a primary Axis II diagnosis of a borderline,
antisocial, schizoid, schizotypal personality disorder will
be excluded, because they need highly specialized
treatment. Patients in whom there is a suspicion of an autism
spectrum disorder (based on a sum score on the
AutismSpectrum Quotient (AQ) higher than 32) , who have
an IQ less than 80 (in case of suspicion an intelligence test
is taken), and problems with the Dutch language (talking,
reading, writing) will also be excluded.
Inclusion and exclusion procedure and randomization
Patients who are registered for treatment at the
department of anxiety disorders will be screened on the
presence of Axis I disorders by the intake clinician. Eligible
patients are patients diagnosed with SAD, or in the case
of more than one Axis I diagnosis (e.g. panic disorder or
depressive disorder), patients for whom social anxiety
should be the principal focus of treatment, according to
both patient and clinical staff. At first instance these
patients will receive concise information about the study
by the intake clinician. At PsyQ The Hague they will
then receive a leaflet containing information about the
study, which is sent by mail after a research assistant has
informed the patient by phone. At PsyQ Rotterdam the
leaflet is handed over at the first appointment by the
intake clinician or during a second appointment in which
the patient is given treatment advice. Patients of that
location will be contacted by the research staff after the
Axis II diagnosis of APD is established.
Eligible patients are invited for a diagnostic interview —
consisting of the Structured Clinical Interview for
DSMIV Axis II Personality Disorders (SCID-II) — to determine
the presence of Axis II disorders and other inclusion and
exclusion criteria. Beforehand patients receive the AQ and
the pre-screener of the SCID-II. During the SCID-II
interview all cluster C personality disorders are fully
investigated. All confirmatively answered and all unanswered
questions on the pre-screener will also be assessed with
the SCID-II interview. If the personality trait is confirmed
and the amount of confirmed traits pertaining to a certain
personality disorder exceeds three, all traits pertaining to
that personality disorder will be assessed with the SCID-II
interview. Besides scores on the pre-screener, clinical
judgement can also be a reason to fully examine a certain
personality disorder. In addition to SCID-II, the
MiniInternational Neuropsychiatric Interview (MINI), section
social anxiety, is also administered. The MINI interview is
part of the intake procedure of both anxiety departments
of PsyQ in addition to a general clinical interview. Some
of the patients entering this study will have recently signed
up for treatment and will have completed this procedure,
but referral by other departments or during ongoing
treatment is also possible. It was therefore decided to add the
SAD section of the MINI to ensure that patients included
meet the inclusion criteria of both SAD and APD.
During the examination, patients will receive
additional verbal and extensive written information about
the study with respect to both treatment conditions and
consequences of participating. After conclusion of the
SCID-II administration, patients will be either informed
directly or receive a follow-up appointment to discuss
the findings of the interview. Patients will have 2 weeks
to consider participation, after which they will be
contacted by a research assistant. Written informed
consent will be obtained from patients who are willing to
participate, and they will be asked to fill in the baseline
assessment comprising different self-report
questionnaires. To be able to assess the frequency and severity of
manifestations of APD, a semi-structured interview was
developed: the AVPDSI. The AVPDSI interview is
administered by phone by a trained psychologist or a
trained master student in clinical psychology who fulfils
a traineeship at the PsyQ anxiety department.
After a final file check of inclusion and exclusion criteria
based on the patient file and after all baseline measures are
completed, a research assistant will randomize the patients
to the GCBT or GST condition using a
computergenerated list (https://www.random.org/lists/). Patients will
be randomized in pairs or multiples of pairs. In case of
uneven dropout from treatments, a weighted randomization
will be done to prevent one of the groups from becoming
too small. For both locations this will be done separately.
The main researchers and other outcome adjudicators
are blind to group assignment to protect integrity of
data collection and analysis. Because it is impossible for
a therapist to offer and for a patient to receive therapy
without being aware of the techniques they are using or
receiving, therapists and patients are not blind. Finally,
because data collectors are also employed as therapists
in the anxiety departments of the participating sites, they
are able to access patient records. Therefore, data
collection of clinician-administered measures cannot be
blinded. To reduce the risk of biased data collection,
therapists involved in delivering either the GCBT or
GST are not involved in data collection.
Different guidelines recommend CBT for treatment of
SAD [28–30]. CBT is seen as the gold standard for SAD
with respect to non-pharmacological treatment, and gains
achieved with CBT seem to persist longer than those
achieved with pharmacotherapy . Guidelines differ
with respect to the advised treatment format (individual
or group therapy). The Canadian guidelines do not
express any preference, NICE guidelines advise individual
CBT and Dutch guidelines recommend group CBT [28–
30]. None of these guidelines advises on the treatment of
SAD and comorbid APD. With respect to APD, guidelines
are scarce. Dutch multidisciplinary guidelines recommend
group behavioral treatment for patients with APD. They
specify that in case of comorbidity of SAD and APD, CBT
is seen as an adequate treatment option, although
prolonged treatment is necessary to realize comparable
favourable outcomes as for SAD only .
GCBT is a regular treatment option and fits neatly in
the health care program offered at the RCT participating
departments of anxiety disorders. GST will be a new
treatment, but will be performed by skilled and
experienced therapists. Both treatments were piloted in
advance to enable therapists to become acquainted with
the treatment protocol and the semi-open group format.
In the ST condition therapists had no former experience
with ST in a group format; therefore, this treatment
modality was permitted an 8 months longer pilot period. In
The Hague the pilot period for GST was 18 months and
for GCBT 10 months. In Rotterdam the pilot period for
GST took 32 months and for GCBT 24 months, this was
due to a major reorganisation.
For patients of both GST and GCBT, treatment
comprises of 30 weekly group sessions of 90 minutes,
preceded by 2 introductory individual sessions of
45 minutes. In addition to the group treatment, limited
individual time with the therapist is permitted with a
maximum of 180 minutes. Individual contact can take
place in person or by phone or e-mail and can be
initiated by either patient or therapist, for instance if urgent
personal matters come up or if the therapist fears
dropout and wants to discuss possible obstacles for the
patient. Sessions will be audiotaped to assess protocol
adherence. For both GST and GCBT, customized rating
forms will be developed and a random selection of tapes
will be listened to in order to evaluate to what extent
therapists adhere to the protocol.
Group schema therapy (GST)
GST is a recently developed treatment for personality
disorders. GST is shorter, more directive,
confrontational and integrative — using experiential, cognitive
and behavioral techniques, addressing childhood and
present — than traditional psychodynamic
psychotherapies for personality disorders. Schemas can be
described as psychological constructs that include beliefs
that we have about ourselves, the world and other
people, which result from interactions of innate
temperament and early environmental factors, notably
trauma and unmet core childhood needs. When
maladaptive schemas are triggered, specific states occur, as
the result of the combination of activated schema(s)
and type of coping, that can be described as schema
modes. Schema modes are central in GST. Schema
modes often had an adaptive role in childhood (e.g. in
terms of survival in an adverse situation), but become
maladaptive and limiting in adulthood. GST aims at
reducing the use of dysfunctional coping modes, healing
the maladaptive child modes, banishing the internalized
parent modes and strengthening the adaptive modes
(healthy adult mode and happy child mode). The
ultimate goal of GST is to enable patients to get their
emotional needs met, including gaining autonomy and
forming healthy social relationships. In GST the group
is used as an analogue for the family of origin with the
other group members as ’siblings’ and the therapists as
’parents’. Group processes can be used to create
corrective emotional experiences and to reduce
maladaptive coping modes .
For this study, a 30-session treatment protocol of
90minute weekly sessions over 9 months was developed.
The treatment protocol is naturalistic in the sense that,
apart from the framework directing treatment focus
throughout sessions, therapists do not have a session-to
session detailed treatment manual. The structure of the
group will be semi-open, and every 10 weeks new
patients can enter an ongoing group. Before a patient
enters the group, two individual meetings will be planned
to provide some information about the content and the
process of GST, to discuss briefly the results of the
Schema Mode Inventory (SMI) and to formulate a case
conceptualization in schema mode terms in
collaboration with the patient.
Participants are encouraged to engage in homework
between sessions to gain corrective experiences in line
with individual needs. Thus, homework does not focus
on exposure to social situations that are feared, but on
finding ways to better meet one’s needs. Each course will
be provided by two experienced therapists who received
formal GST training by Farrell and Shaw. They will
receive monthly supervision (1.5–2 hours) by Farrell and
Shaw using Skype.
Group cognitive behavioral therapy (GCBT)
GCBT will follow a prolonged version of the
wellinvestigated protocol of Heimberg and colleagues of group
therapy for SAD [31–33] in combination with some new
insights in the working mechanisms of exposure in vivo
. GCBT will mainly consist of simulated exposures to
feared situations in-session, cognitive restucturing and in
vivo exposure to feared social situations between sessions.
Just as in the GST, the format of the group will be
semiopen, allowing new patients to enter the group every
10 weeks, and the group treatment of 30 weekly sessions is
preceded by 2 individual sessions.
The individual sessions are aimed at facilitating the start
of the group treatment. During these sessions information
about the content of the therapy is provided and an
individual case conceptualization is drawn. Emphasis will be
placed on the role of avoidance and safety-seeking
behaviors in the maintenance of SAD. The basics of cognitive
restructuring will be presented, and patients will be asked to
write down a list of feared situations which will be placed
in a hierarchical sequence. Social anxiety will be considered
as a learned response to social situations incorporating
interactive physiological, behavioral and cognitive features.
Social anxiety disordered patients supposedly fear most
social situations because of their expectancies to be
humiliated or rejected by others or confrontations with their own
supposed social inadequacies and failure. The main
therapeutic target in GCBT is the disconfirmation of these
dysfunctional expectancies. To a small extent one strives for
these disconfirmations using traditional cognitive
procedures such as identification, intellectual challenging and
(possibly) correcting of dysfunctional opinions. By far the
largest part of the CBT procedure of disconfirming such
expectancies exists of exposure in vivo. Since the
understanding of the working mechanisms of exposure in vivo
has changed in recent years, the main target of exposure in
vivo is no longer habituation of the fear response.
Nowadays it is believed that exposure in vivo sets off a process
of inhibition in which the association of the conditioned
stimulus (CS) (social situations) and the feared
unconditioned stimulus (US) (humiliation) is inhibited by the
forming of new associations around the CS, of which the
association with ‘no-US’ (no rejection) is probably the most
important . During group sessions and for homework,
patients expose themselves deliberately to the social
situations they fear in order to let new non-anxious associations
form and to experience in particular that the negative
consequences they expected in advance did not become true
in reality. Noticing the differences between the expected
and the actual outcomes of these confrontations is an
important subject for therapeutic discussion after
exposure. Therefore, the GCBT protocol is a mix of the
wellproven approach of Heimberg and some new insights in
the mechanisms of exposure in vivo.
Most group sessions will focus mainly on
performancebased gradual and systematic exposure with elimination of
the accompanying safety behaviors. Self-exposure to
situations that resemble the exposure practiced in-session is
prescribed as homework to further promote correction of
negative expectancies. GCBT is highly structured, with each
session following the same agenda including discussing
homework assignments, in-session performance-based
exposure and assigning new homework. The group is used to
provide an immediate exposure setting while it offers the
possibility of vicarious learning from other group members
at the same time. The group is, however, mainly
disorderspecific in a sense that the primary goal is reduction of
social anxiety symptoms. In contrast to GST group processes,
childhood experiences and experiential exercises will not be
used to promote symptom reduction. Each course will be
provided by two experienced cognitive behavioral therapists
who have been trained in the specific GCBT protocol.
During the trial the therapists will receive supervision every
2 weeks (0.45 to 1 hour) by a licensed CBT supervisor.
Dropout and follow-up
In case of emergencies (like severe increase of symptoms,
suicidality) deviation from the protocol is allowed.
Subjects can leave the study at any time for any reason if they
wish to do so. The researcher can — in consultation with
the group therapists — also decide to withdraw a subject
from the study for urgent medical or psychological
reasons. Reasons for dropout or withdrawal will be registered.
Patients who withdraw from treatment will also be asked
to complete follow-up assessments. As mentioned before,
during the active treatment phase, participation in other
treatments, starting medication or raising the medication
dosage is not allowed. Also missing too many sessions is
not permitted (patients should at least attend a minimum
of 80 % of the sessions); if too many are missed, treatment
will be terminated (pushout). In consultation with the
patient, taking into account the reason for dropout, a
suitable alternative will be discussed.
The follow-up period is experimental for the first
3 months (patients are not provided additional treatment
unless clinically deemed necessary, e.g. in case of crisis).
After this period, patients are offered an appointment
with one of the group therapists. Depending on the wish
of the patient, main treatment results and further
treatment needs can be discussed. From then on follow-up
will be naturalistic, meaning that patients are free to
seek help in case of unsatisfactory treatment results and/
or additional need for treatment.
The measures described below will be administered on
different measurement occasions. At all time points
selfreport measures will be conducted online, except for the
AQ and pre-screener of the SCID-II used in the
inclusion and exclusion procedure (see inclusion procedure
above). On request, participants can complete the
selfreport measures on paper.
The administration of the SCID-II and the MINI during
the intake phase will be conducted face to face. At the last
assessment (T5) patients can choose between a
face-toface or telephone administration of the SCID-II, APD
section and the MINI, SAD section, according to their
preference. For practical reasons, all AVPDSI assessments are
administered by phone. Research supports the validity of
structured telephone interviews for data collection from
primary care patients . See Fig. 1 for the exact
measurements per occasion. To ensure privacy of participants
and safe data storage, data will be entered in a data file
anonymously; participants will be given a unique number,
and only the research assistant will be able to link the
number with the name of the patient. Data will be stored
on a laptop used only for research purposes, and a salted
and encrypted file server which has been advised by an
independent tech consultant.
Primary outcome measures
The primary outcome measure for severity of social
anxiety is the self-report version of the Liebowitz Social
Anxiety Scale (LSAS-SR). The objective of the LSAS  is to
assess the range of social interaction and performance in
situations which patients with SAD may fear. The scale
contains two parts: one part measures the level of anxiety,
and the other part measures the level of avoidance. It
consists of 24 items, 13 relating to performance anxiety and
11 concerning anxiety in social situations . The LSAS
was originally developed as a clinician-administered
semistructured interview. The LSAS self-report version has
comparably good psychometric properties (convergent
and discriminant validity, internal consistency, test-retest
reliability, criterion validity), high correlation with the
clinician-administered version and sensitivity to treatment
change. Furthermore, the self-report version is easier to
administer and is less time-consuming for both patient
and clinician [38–40]. The LSAS-SR will be administered
at all time points, i.e. at the start, halfway and at the end
of the treatment period and during follow-up at 3, 6 and
12 months after study treatment (see Fig. 1).
The primary outcome measure for severity of APD is
the clinician-administered Avoidant Personality Disorder
Severity Index (AVPDSI). The AVPDSI is a
semistructured interview developed specifically for this study
to assess the frequency and severity of manifestations of
APD, as defined in the DSM-IV/5, during the last month.
The purpose of this instrument is to yield a quantitative
index of the current severity of APD manifestations, in
terms of both avoidance and fear. The AVPDSI is
modelled after the Borderline Personality Disorder Severity
Index (BPDSI), which was originally developed by Weaver
and Clum  and further developed and validated in
Dutch by Arntz et al.  and Giesen-Bloo et al. . The
information gathered by the AVPDSI in the context of the
RCT will also be used in a larger study in which the
psychometric properties of the interview will be assessed. To
ensure quality of data collection of this newly developed
instrument, a training protocol will be developed and all
measurements will be audiotaped. A random selection of
tapes will be listened to in order to assess interrater
reliability. This semi-structured interview will be conducted
before the start of treatment and at 3 and 12 months
follow-up (see Fig. 1).
Secondary study parameters
Mini-International Neuropsychiatric Interview (MINI), social
anxiety disorder section
The presence of SAD will be assessed with this section
of the MINI [44, 45] as a part of the inclusion procedure
and at 12 months follow-up (see Fig. 1). The validation
of the Dutch translation of the clinician rated (CR)
version of the MINI  against the Structured Clinical
Interview DSM-III-R-patient version (SCID-P) and the
Composite International Diagnostic Interview for
ICD10 (CIDI) showed good to very good kappa values .
Structured Clinical Interview for DSM Axis II Disorders
(SCID-II), APD section
The APD section of SCID-II will be used to assess the
presence of APD during inclusion and 12 months after
treatment (see Fig. 1). Studies found adequate to good
interrater reliability for SCID-II interviews [47–49].
Schema Mode Inventory 2 (SMI-2)
The SMI-2  is a modified version of the SMI-1 
and successfully distinguishes between patients and
controls. Newly formulated modes proved to be appropriate
for histrionic, avoidant and dependent personality
disorder. The results supported recent theoretical
developments in schema therapy (ST). The questionnaire is
useful for application in clinical practice. Questions from
the SMI-1  concerning the happy child mode were
added to the SMI-2 because of its putative therapeutic
relevance in the ST treatment for patients with APD.
Inventory of Depressive Symptomatology Self-Report
Depressive symptomatology is measured by the IDS-SR
, which encompasses all the relevant symptoms for
major depressive disorder based on the DSM-IV . It
consists of 30 items, with total scores ranging from 0–84
(only 28 of the 30 items are rated, with each item rated 0–
3) . The questionnaire has highly acceptable
psychometric properties with reasonable internal consistency,
interrater reliability and concurrent and discriminant
validity and is a sensitive measure of symptom severity in
depression [51, 53]. The self-report version is as sensitive to
change as the clinician-administered version .
World Health Organization Quality of Life–BREF
The WHOQOL-BREF  was developed as an
international cross-culturally comparable self-report quality of
life assessment instrument. It assesses the individual’s
perceptions of quality of life in the context of their culture
and value systems, personal goals, standards and concerns
across four domains: physical health, psychological health,
social relationships and environment. The internal
consistency of the four domains of the WHOQOL-BREF
ranged from 0.66 to 0.80. Domain scores of the
WHOQOL-BREF correlated around 0.92 with the
WHOQOL-100 domain scores. Relatively low correlations
were found between demographic characteristics (age and
sex) and WHOQOL-BREF domain scores. It is concluded
that the content validity, construct validity and the
reliability of the WHOQOL-BREF in a population of adult Dutch
psychiatric outpatients are good .
Difficulties in Emotion Regulation Scale (DERS)
The DERS  is a 36-item self-report questionnaire
consisting of six subscales: (1) Non-acceptance of
emotional responses (6 items); (2) Difficulties engaging in
goal-directed behavior (5 items); (3) Impulse control
difficulties (6 items); (4) Lack of emotional awareness (6
items); (5) Limited access to emotion regulation
strategies (8 items); (6) Lack of emotional clarity (5 items).
The internal consistency for the total scale as well as for
the subscales appeared to be adequate (varying between
a Cronbach’s alpha of 0.80 and 0.93). The questionnaire
also has adequate construct and predictive validity and
good test-retest reliability.
The Rosenberg Self-Esteem Scale (RSES)
The RSES will be used to assess self-esteem. It is a
widely used 10-item Likert scale self-esteem measure.
Items are answered on a 4-point scale — from strongly
agree to strongly disagree — measuring positive and
negative feelings towards the self . The Dutch
version of the RSES is found to be a one-dimensional scale
with high internal consistency and congruent validity
and a Cronbach’s alpha of 0.89 .
Acceptance and Action Questionnaire (AAQ-II)
The AAQ-II  is a self-report measure designed to
assess experiential avoidance. It consists of 10 items which
are scored on a Likert scale from 1 to 7 with total scores
that vary from 10 to 70. Higher scores are indicative of
more acceptance and less experiential avoidance. It
appears to be a unidimensional measure with sound factor
structure and good reliability and validity. The mean
alpha coefficient is .84 and the 3- and 12-month
testretest reliability scores are .81 and .79 respectively .
Construct validity, internal consistency, convergent and
divergent validity of the Dutch version are comparable
with the English version .
Childhood Trauma Questionnaire-Short Form (CTQ-SF)
The aforementioned questionnaires SMI-2, IDS-SR,
WHOQOL-BREF, DERS, RSES and AAQ-II are
conducted at all time points (see Fig. 1). In addition to
outcome measures, information on sociodemographic and
clinical history variables will be collected at baseline. To
assess childhood trauma, the CTQ short form  is
chosen. The short form was developed from the original
version of the CTQ which has 70 items . Because of
its brevity of administration and assessment of multiple
types of maltreatment, it is well suited for treatment
studies like this RCT. The short form consists of 28
items measuring physical, sexual and emotional abuse
and physical and emotional neglect, and its reliability
and criterion-related validity have been established .
A recent study in the Netherlands among a large sample
of participants (2308) with or without a current
depressive and/or anxiety disorder concludes that the
fivefactor model fits the data well, that the total scores
represent a broad dimension of maltreatment during
childhood and that the factorial validity and reliability data
make it a good instrument for various forms of abuse
and neglect in childhood in clinical settings .
In the inclusion procedure the MINI and the SCID-II,
which are both described above, are used to assess
respectively Axis I and II disorders. In addition, patients
are screened with the Autism-Spectrum Quotient (AQ).
Autism-Spectrum Quotient (AQ)
Since the presence of an autism spectrum disorder
(ASD) requests a highly specific treatment and patients
with an ASD would probably not benefit from the
treatments offered in the RCT, it was decided to exclude
patients with a score exceeding the clinical cut-off score on
the Autism-Spectrum Quotient (AQ). Patients who score
above the cut-off are offered referral for full diagnostic
assessment. The AQ is a short self-administered scale
for identifying the degree to which any individual adult
of normal IQ may have autistic traits. Individuals score
in the range 0–50. The higher the score, the more
autistic traits a person possesses [27, 63] with a cut-off of 32
for distinguishing individuals with clinically significant
levels of autistic traits . The AQ comprises 50
questions assessing five different areas: social skill, attention
switch, attention to detail, communication and
imagination. It has reasonable construct and face validity and
good test-retest and interrater reliability  and is a
useful screening instrument in clinical practice . The
Dutch translation has been shown to be a reliable
instrument to assess autism spectrum condition (ASC) traits
and has satisfactory internal consistency and test-retest
reliability. High total AQ scores are specific to patients
with an ASD and set them apart from both the general
population and from patients with SAD .
Pre-test differences between both treatment groups and
between treatment completers and dropouts will be
calculated by means of independent t tests, nonparametric tests
or chi-square tests when appropriate. Multilevel analysis
(MLA) will be used to investigate the effectiveness of
GCBT and GST in reducing social anxiety symptoms and
manifestations of AVPD, and the secondary outcomes.
MLA is especially suitable to analyse repeated measure data
because it takes into account the dependencies among
observations nested within individuals. Another advantage of
this methodology is its ability to handle missing data, a
problem often occurring in longitudinal research . The
data has a three-level hierarchical (multilevel) structure:
repeated measures at the first level, individuals at the second
level, treatment condition at the third level. For
dimensional outcomes the appropriate underlying distribution
(e.g. normal, gamma, negative binomial) will be determined
based on the observed distributions of residuals. For the
repeated part, the best fitting covariance structure will be
determined empirically. Moreover, multilevel logistic
regression analysis will be performed in order to investigate
whether GCBT compared to GST results in a higher
proportion of remitted APD. Survival analysis will be used to
compare conditions in treatment retention. The
identification of possible predictors, moderators and mediators will
be based upon the recommendations of Kraemer .
Linear regression methods will be applied to identify
predictors/moderators related to treatment outcome.
Bootstrapping methods  will be used to investigate the
mediating effects of, for example, emotion regulation on
symptom reduction. Furthermore, effect sizes and clinical
significant change according to the Jacobson and Truax
criteria  will be calculated to estimate respectively the
magnitude of the treatment effect and the significance of
the results for clinical practice.
This article describes the study protocol of an RCT
comparing group CBT and group ST for patients with SAD
and comorbid APD. Evidence of the effectiveness of
group ST on PDs other than borderline personality
disorder (BPD) is sparse , and to the best of our
knowledge, this is the first study on group ST for this specific
patient group. Therefore, this trial can provide valuable
information on the effectiveness of ST offered in a group
format as a treatment option for these patients. It will
also extend our knowledge on prolonged CBT, which is
the advised treatment for patients with APD according
to the Dutch treatment guidelines for treatment of
personality disorders .
Research on the optimal treatment of APD is scarce.
Most studies have investigated treatment of SAD and
compared the outcome of patients with and without
comorbid APD . APD is in general relatively
understudied , although it is one of the most prevalent
personality disorders across community and clinical
samples and is known by its significant functional
impairment [71–73]. Since APD is often comorbid with
SAD, with data on comorbidity varying between 32–
50 % , this study can provide clinically relevant
information for a substantial group of patients with APD.
The current study has several strengths. The chosen
design, an RCT, is recognized to be the best and most
definitive way of demonstrating that an intervention is effective
. Both treatments are well documented [17, 24, 75]
and have been implemented in scientific research before
in treatment studies for GCBT (e.g. [76–79]) and
individual and group ST (e.g. [19, 43, 80, 81]).
Treatments will be provided by therapists with ample
experience in anxiety treatment in specialized mental
health care. Besides being trained in the treatment
protocol, therapists will be supervised by experienced
CBT and ST supervisors.
Both treatment protocols will be suitable for use in a
clinical setting. The semi-open character of the groups,
in which influx of patients is allowed every 10 weeks,
diminishes waiting time and is therefore an ethical
solution in case of long waiting lists as a consequence of
lengthy treatments for patients with severe
psychopathology. Also, from an organizational perspective, in which
limitation of waiting time is considered important, this
format can be attractive and might possibly even offer a
cost-effective option for treatment of APD . The
semi-open character enables formation of groups with
comparable psychiatric morbidity, allowing for contact
with fellow patients. The size of the intended study
sample will be sufficient to reliably detect differential
treatment effects of a medium effect size or larger, and
the relatively limited waiting time is expected to have a
positive effect on the influx of patients. The selected
measuring instruments are scientifically sound, and the
repeated measurements allow for a close monitoring of
changes in time, as well as mediation analyses of
putative working mechanisms. The follow-up period of one
year enables us to monitor how patients fare after the
However, there are also some limitations to consider,
given the chosen research design. The decision to
compare GST with GCBT, with GCBT as treatment as usual
(TAU), instead of a no-treatment or attention control
condition might affect internal validity, since it sets
boundaries on the possibility to control for other
potentially influencing factors not directly related to the
therapeutic context. When the effects of both treatments
prove to be not significantly different, the absence of an
inactive condition implies that one cannot exclude the
possibility that factors such as passage of time or
attention may have critically influenced outcomes observed.
The influence of the factor time is, however, expected to
be limited, since APD, like other personality disorders, is
by definition assumed to be persistent , and recent
studies show that APD symptoms are relatively stable
over time [71, 82, 83]. Moreover, the addition of a
control group would, in our opinion, have some serious
ethical consequences, because it would deprive help-seeking
patients of treatment for too long a period of time.
Also one might argue the validity — for this specific
patient group — of GCBT as TAU, because of the relative
paucity of scientific evidence for prolonged CBT for APD.
Although we subscribe the need for additional scientific
evidence, we feel that prolonged GCBT can be considered
as TAU based on Dutch guidelines  and earlier studies
on SAD with comorbid APD  or APD with or without
comorbid SAD [84–86].
Another point to consider is that both treatments
consist of two individual sessions followed by 30 group
sessions. A ST treatment of thirty sessions is relatively
short. Most published RCTs investigating ST treatments
thus far comprise 50 or more sessions covering time spans
of more than one year [19, 81, 87]. A longer duration of
treatment might possibly show greater improvements on
the outcome measures. On the other hand, the RCT of
Farrell et al.  compared the effectiveness of adding 30
group sessions of ST to TAU and TAU alone in patients
with BPD and found significantly greater reductions in
BPD symptoms and global severity of psychiatric
symptoms in the GST. So we expect that this treatment period
will be long enough to detect differential effects of
treatment if present.
The semi-open structure of the group treatments
might have disruptive effects on the course of therapy
because of patients entering and leaving at several time
points. The possible difficulties experienced by the
newcomers are addressed by adding two individual sessions
and by reframing something that might be frightening
into something positive (e.g. for CBT to facilitate
exposure, and for ST to provoke dysfunctional modes, which
can subsequently be addressed). One cannot rule out
that this treatment format might influence effectiveness
and that this effect is different for both treatment
Furthermore, execution of the multicentre RCT in two
large cities in the Netherlands and under tightly controlled
conditions might have implications for generalizability
and external validity. When treatment results are
promising, implementation studies of ST under more naturalistic
conditions (benchmark studies) are needed to obtain
further evidence for the treatment modalities.
In conclusion, this RCT will extend our knowledge on
the effectiveness of both GCBT and GST and will give us
an opportunity to examine if GST is a valuable option
for patients suffering from SAD in combination with
APD. Moreover, the results will inform us if the effects
of GST exceed those of existing practices mainly
consisting of prolonged CBT interventions.
Since people with this double diagnosis report a low
quality of life and are seriously impaired in social
interactions and fulfilling social relationships with a negative
impact on their well-being, developing and testing an
additional and easily applicable treatment option will have
both scientific, clinical and individual value, taking us a
step forward in treating these severely disabled patients.
The trial was registered on 25 March 2013 in the Dutch
Trial Register (NTR3921). Participants are currently
being recruited and enrolled. The trial started recruitment
in March 2014 at PsyQ The Hague and in May 2015 at
Additional file 1: SPIRIT flow diagram. (PDF 143 kb)
Additional file 2: SPIRIT checklist. (PDF 160 kb)
AAQ-II: Acceptance and Action Questionnaire; APD: Avoidant personality
disorder; AQ: Autism-Spectrum Quotient; ASC: Autism spectrum condition;
AVPDSI: Avoidant Personality Disorder Severity Index; BPD: Borderline personality
disorder; BPDSI: Borderline Personality Disorder Severity Index; CBT: Cognitive
behavioral therapy; CS: Conditioned stimulus; CTQ-SF: Childhood Trauma
Questionnaire-Short Form; DERS: Difficulties in Emotion Regulation Scale;
GCBT: Group cognitive behavioral therapy; GST: Group schema therapy;
IDSSR: Inventory of Depressive Symptomatology Self-Report; LSAS-SR: Liebowitz
Social Anxiety Scale Self-Report; LUMC: Leiden University Medical Centre;
MEC: Medical Ethical Committee; MINI: Mini-International Neuropsychiatric
Interview; MLA: Multilevel analysis; RCT: Randomized controlled trial;
RSES: Rosenberg Self-Esteem Scale; SAD: Social anxiety disorder;
SCIDII: Structured Clinical Interview for DSM-IV Axis II Personality Disorders;
SMI2: Schema Mode Inventory 2; ST: Schema therapy; TAU: Treatment as usual;
US: Unconditionned stimulus; WHO-QOL-BREF: World Health Organization
Quality of Life–BREF
The study is supported by PsyQ, University of Leiden and University of
Amsterdam. Both for GST and for GCBT, treatment protocols had to be
adapted to the semi-open format of the groups. We give particular thanks to
Joan Farrell and Ida Shaw for their contribution to the ST protocol and for
giving us permission to use their materials in this RCT.
All authors were involved in the conception and design of the study. AB and AG
drafted the manuscript. AvG, KK, AA and PS helped to revise the manuscript. All
authors read and approved the final manuscript.
Ethics approval and consent to participate
Ethical approval was received from the Medical Ethical Committee (MEC) of
the Leiden University Medical Centre (LUMC) in Leiden, the Netherlands
(protocol number p12.165). In case of necessary deviations from protocol —
although improbable — amendments will be submitted to the MEC. Written
informed consent will be obtained from patients who are willing to
participate before enrolment to the trial.
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