title: Design of a multicentered randomized controlled trial on the clinical and cost effectiveness of schema therapy for personality disorders.
abstract: BACKGROUND
  Despite international guidelines describing psychotherapy as first choice for people with personality disorders (PDs), well-designed research on the effectiveness and cost-effectiveness of psychotherapy for PD is scarce. Schema therapy (ST) is a specific form of psychological treatment that proved to be effective for borderline PD. Randomized controlled studies on the effectiveness of ST for other PDs are lacking. Another not yet tested new specialized treatment is Clarification Oriented Psychotherapy (COP). The aim of this project is to perform an effectiveness study as well as an economic evaluation study (cost effectiveness as well as cost-utility) comparing ST versus COP versus treatment as usual (TAU). In this study, we focus on avoidant, dependent, obsessive-compulsive, paranoid, histrionic and narcissistic PD.
  
  
  METHODS
  In a multicentered randomized controlled trial, ST, and COP as an extra experimental condition, are compared to TAU. Minimal 300 patients are recruited in 12 mental health institutes throughout the Netherlands, and receive an extensive screening prior to enrolment in the study. When eligible, they are randomly assigned to one of the intervention groups. An economic evaluation and a qualitative research study on patient and therapist perspectives on ST are embedded in this trial. Outcome assessments (both for clinical effectiveness and economic evaluation) take place at 6,12,18,24 and 36 months after start of treatment. Primary outcome is recovery from PD; secondary measures include general psychopathological complaints, social functioning and quality of life. Data for the cost-effectiveness and cost-utility analyses are collected by using a retrospective cost interview. Information on patient and therapist perspectives is gathered using in-depth interviews and focus groups, and focuses on possible helpful and impeding aspects of ST.
  
  
  CONCLUSIONS
  This trial is the first to compare ST and COP head-to-head with TAU for people with a cluster C, paranoid, histrionic and/or narcissistic PD. By combining clinical effectiveness data with an economic evaluation and with direct information from primary stakeholders, this trial offers a complete and thorough view on ST as a contribution to the improvement of treatment for this PD patient group.
  
  
  BACKGROUND
  Netherlands Trial Register (NTR): NTR566.
authors.affiliation: Department of Clinical Psychological Science, Faculty of Psychology, Maastricht University, Maastricht, The Netherlands. l.bamelis@maastrichtuniversity.nl
authors.forename: Lotte L M
authors.initials: LL
authors.lastname: Bamelis
authors.forename: Silvia M A A
authors.initials: SM
authors.lastname: Evers
authors.forename: Arnoud
authors.initials: A
authors.lastname: Arntz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003362:Cost-Benefit Analysis; D006801:Humans; D008875:Middle Aged; D009426:Netherlands; D010554:Personality Disorders / Q000628:therapy*; D011613:Psychotherapy / Q000191:economics* / Q000379:methods*; D012107:Research Design; D055815:Young Adult