Group schematherapy versus group cognitive behavioral therapy for social anxiety disorder with comorbid avoidant personality disorder.

Social phobia with comorbid avoidant personality disorder has a high prevalence and is associated with serious psychosocial problems and high societal costs. The current multidisciplinary guidelines advice to offer prolonged CBT in case of social anxiety disorder with avoidant personality disorder. There is increasing evidence for the effectiveness of group schema therapy (GST) for personality disorders. GST focuses on changing the underlying dysfunctional schemas and coping strategies. Until now, it is unknown whether GST for social phobia and comorbid avoidant personality disorder is more effective than CBT.

Patients included in this trial will be diagnosed with both

social anxiety disorder and avoidant personality disorder.

Improvements can thus be realized on 2 different domains,

namely with respect to severity of social anxiety disorder and

with respect to avoidant personality disorder. Since no

previous studies have been conducted with this specific

patient group, there are no a priori hypotheses about

differences in treatment effectiveness.

1. M 1 - 3: Preparations;

2. M 3 - 24: Screening (M0) and treatment;

3. M 9 – 29: Midtests (M1);

4. M 14 – 34: Posttests (M2);

5. M 20 - 40: 6- month follow-up 6 (M3);

6. M 26 - 46: 12- month follow-up (M4);

7. M 26 – 60: Analyses and publications.

Changed 28-jun-2016: Measurements will be done at start (T0), halfway (T1) and at the end (T2) of the treatment period and during follow up at 3 (T3), 6 (T4) and 12 months after study treatment (T5).

1. The self-report version of the Liebowitz Social Anxiety Scale (LSAS-SR) will be used as primary outcome for social anxiety disorder. The LSAS-SR assesses the range of anxiety in social interaction and performance in situations which patients with social anxiety disorder may fear.

2. The primary outcome measure for severity of avoidant personality disorder is the clinician-administered Avoidant Personality Disorder Severity Index (AVPDSI). The AVPDSI is a semi-structured interview developed specifically for this study to assess the frequency and severity of manifestations of avoidant personality disorder, as defined in the DSM-IV/5, during the last month. Both therapies will be given in 30 sessions of 90 minutes.