title: Patient adherence predicts outcome from cognitive behavioral therapy in obsessive-compulsive disorder.
abstract: OBJECTIVE
  To examine the effects of patient adherence on outcome from exposure and response prevention (EX/RP) therapy in adults with obsessive-compulsive disorder (OCD).
  
  
  METHODS
  Thirty adults with OCD were randomized to EX/RP (n = 15) or EX/RP augmented by motivational interviewing strategies (n = 15). Both treatments included 3 introductory sessions and 15 exposure sessions. Because there were no significant group differences in adherence or outcome, the groups were combined to examine the effects of patient adherence on outcome. Independent evaluators assessed OCD severity using the Yale-Brown Obsessive Compulsive Scale. Therapists assessed patient adherence to between-session EX/RP assignments at each session using the Patient EX/RP Adherence Scale (PEAS). Linear regression models were used to examine the effects of PEAS scores on outcome, adjusting for baseline severity. The relationship between patient adherence and other predictors of outcome was explored using structural equation modeling.
  
  
  RESULTS
  Higher average PEAS ratings significantly predicted lower posttreatment OCD severity in intent-to-treat and completer samples. PEAS ratings in early sessions (5-9) also significantly predicted posttreatment OCD severity. The effects of other significant predictors of outcome in this sample (baseline OCD severity, hoarding subtype, and working alliance) were fully mediated by patient adherence.
  
  
  CONCLUSIONS
  Patient adherence to between-session EX/RP assignments significantly predicted treatment outcome, as did early patient adherence and change in early adherence. Patient adherence mediated the effects of other predictors of outcome. Future research should develop interventions that increase adherence and then test whether increasing adherence improves outcome. If effective, these interventions could then be used to personalize care.
authors.affiliation: Department of Psychiatry, Columbia University.
authors.forename: Helen Blair
authors.initials: HB
authors.lastname: Simpson
authors.affiliation: Anxiety Disorders Clinic, New York State Psychiatric Institute.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Maher
authors.affiliation: Department of Biostatistics, Mailman School of Public Health, Columbia University.
authors.forename: Yuanjia
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Division of Epidemiology, New York State Psychiatric Institute.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Bao
authors.affiliation: Department of Psychiatry, University of Pennsylvania School of Medicine.
authors.forename: Edna B
authors.initials: EB
authors.lastname: Foa
authors.affiliation: Department of Psychiatry, University of Pennsylvania School of Medicine.
authors.forename: Martin
authors.initials: M
authors.lastname: Franklin
mesh_terms: D000328:Adult; D015928:Cognitive Behavioral Therapy; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009771:Obsessive-Compulsive Disorder / Q000628:therapy*; D010349:Patient Compliance; D012720:Severity of Illness Index; D016896:Treatment Outcome