title: Group schema therapy versus group cognitive behavioral therapy for social anxiety disorder with comorbid avoidant personality disorder: study protocol for a randomized controlled trial.
abstract: 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.
  
  
  
  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 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.
  
  
  
  The trial will increase our knowledge on the effectiveness and applicability of both treatment modalities for patients suffering from both diagnoses.
  
  
  
  Dutch Trial Register: NTR3921 . Registered on 25 March 2013.
authors.affiliation: Department of Anxiety, PsyQ, Lijnbaan 4, 2512 VA, The Hague, The Netherlands. astrid.balje@psyq.nl.
authors.forename: Astrid
authors.initials: A
authors.lastname: Baljé
authors.affiliation: Department of Anxiety, PsyQ, Lijnbaan 4, 2512 VA, The Hague, The Netherlands.|Institute of Psychology, Section of Clinical Psychology, Leiden University, Wassenaarseweg 52, 2333 AK, Leiden, The Netherlands.
authors.forename: Anja
authors.initials: A
authors.lastname: Greeven
authors.affiliation: Department of Anxiety, PsyQ, Lijnbaan 4, 2512 VA, The Hague, The Netherlands.|Institute of Psychology, Section of Clinical Psychology, Leiden University, Wassenaarseweg 52, 2333 AK, Leiden, The Netherlands.
authors.forename: Anne
authors.initials: A
authors.lastname: van Giezen
authors.affiliation: Department of Anxiety, PsyQ, Lijnbaan 4, 2512 VA, The Hague, The Netherlands.|Department of Medical and Clinical Psychology Tilburg University, PO Box 90153, 5000 LE, Tilburg, The Netherlands.
authors.forename: Kees
authors.initials: K
authors.lastname: Korrelboom
authors.affiliation: Department of Clinical Psychology, University of Amsterdam, PO Box 15933, 1001 NK, Amsterdam, The Netherlands.
authors.forename: Arnoud
authors.initials: A
authors.lastname: Arntz
authors.affiliation: Department of Anxiety, PsyQ, Lijnbaan 4, 2512 VA, The Hague, The Netherlands.|Institute of Psychology, Section of Clinical Psychology, Leiden University, Wassenaarseweg 52, 2333 AK, Leiden, The Netherlands.
authors.forename: Philip
authors.initials: P
authors.lastname: Spinhoven
mesh_terms: D002985:Clinical Protocols; D015928:Cognitive Behavioral Therapy; D006801:Humans; D017063:Outcome Assessment, Health Care; D010554:Personality Disorders / Q000628:therapy*; D000072861:Phobia, Social / Q000628:therapy*; D011615:Psychotherapy, Group; D012107:Research Design
keywords: Avoidant personality disorder; Group cognitive behavioral therapy; Group schema therapy; Randomized controlled trial; Social anxiety disorder