Abstract
BackgroundSocial 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/designThe 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 Self-Report (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 (AAQ-II). 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.DiscussionThe trial will increase our knowledge on the effectiveness and applicability of both treatment modalities for patients suffering from both diagnoses.Trial registrationDutch Trial Register: NTR3921. Registered on 25 March 2013.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-016-1605-9) contains supplementary material, which is available to authorized users.
Highlights
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
The trial will increase our knowledge on the effectiveness and applicability of both treatment modalities for patients suffering from both diagnoses
The research question can be more explicitly formulated in the following questions: How do the effects of prolonged group cognitive behavioral therapy (GCBT) and group schema therapy (GST) compare for social anxiety disorder? and How do the effects of prolonged GCBT and GST compare for avoidant personality disorder?
Summary
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 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. 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 applicable treatment option will have both scientific, clinical and individual value, taking us a step forward in treating these severely disabled patients.
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