title: Components of therapy as mechanisms of change in cognitive therapy for people at risk of psychosis: analysis of the EDIE-2 trial.
abstract: BACKGROUND
  Research suggests that the way in which cognitive therapy is delivered is an important factor in determining outcomes. We test the hypotheses in which the development of a shared problem list, use of case formulation, homework tasks and active intervention strategies will act as process variables.
  
  
  METHODS
  Presence of these components during therapy is taken from therapist notes. The direct and indirect effect of the intervention is estimated by an instrumental variable analysis.
  
  
  RESULTS
  A significant decrease in the symptom score for case formulation (coefficient = -23, 95% CI -44 to -1.7, P = 0.036) and homework (coefficient = -0.26, 95% CI -0.51 to -0.001, P = 0.049) is found. Improvement with the inclusion of active change strategies is of borderline significance (coefficient = -0.23, 95% CI -0.47 to 0.005, P = 0.056).
  
  
  CONCLUSIONS
  There is a greater treatment effect if formulation and homework are involved in therapy. However, high correlation between components means that these may be indicators of overall treatment fidelity.
authors.affiliation: Clare Flach, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; Paul French, PhD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, Manchester, and Department of Psychological Sciences, Liverpool University, Liverpool; Graham Dunn, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; David Fowler, MSc, School of Psychology, University of Sussex, Brighton; Andrew I. Gumley, PhD, Institute of Health and Wellbeing, University of Glasgow, Glasgow; Max Birchwood, DSc, Division of Mental Health and Wellbeing, University of Warwick, Warwick; Suzanne L. K. Stewart, PhD, Department of Psychology, University of Chester, Chester; Anthony P. Morrison, ClinPsyD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, and School of Psychological Sciences, University of Manchester, Manchester, UK clare.flach@lshtm.ac.uk.
authors.forename: Clare
authors.initials: C
authors.lastname: Flach
authors.affiliation: Clare Flach, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; Paul French, PhD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, Manchester, and Department of Psychological Sciences, Liverpool University, Liverpool; Graham Dunn, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; David Fowler, MSc, School of Psychology, University of Sussex, Brighton; Andrew I. Gumley, PhD, Institute of Health and Wellbeing, University of Glasgow, Glasgow; Max Birchwood, DSc, Division of Mental Health and Wellbeing, University of Warwick, Warwick; Suzanne L. K. Stewart, PhD, Department of Psychology, University of Chester, Chester; Anthony P. Morrison, ClinPsyD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, and School of Psychological Sciences, University of Manchester, Manchester, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: French
authors.affiliation: Clare Flach, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; Paul French, PhD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, Manchester, and Department of Psychological Sciences, Liverpool University, Liverpool; Graham Dunn, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; David Fowler, MSc, School of Psychology, University of Sussex, Brighton; Andrew I. Gumley, PhD, Institute of Health and Wellbeing, University of Glasgow, Glasgow; Max Birchwood, DSc, Division of Mental Health and Wellbeing, University of Warwick, Warwick; Suzanne L. K. Stewart, PhD, Department of Psychology, University of Chester, Chester; Anthony P. Morrison, ClinPsyD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, and School of Psychological Sciences, University of Manchester, Manchester, UK.
authors.forename: Graham
authors.initials: G
authors.lastname: Dunn
authors.affiliation: Clare Flach, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; Paul French, PhD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, Manchester, and Department of Psychological Sciences, Liverpool University, Liverpool; Graham Dunn, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; David Fowler, MSc, School of Psychology, University of Sussex, Brighton; Andrew I. Gumley, PhD, Institute of Health and Wellbeing, University of Glasgow, Glasgow; Max Birchwood, DSc, Division of Mental Health and Wellbeing, University of Warwick, Warwick; Suzanne L. K. Stewart, PhD, Department of Psychology, University of Chester, Chester; Anthony P. Morrison, ClinPsyD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, and School of Psychological Sciences, University of Manchester, Manchester, UK.
authors.forename: David
authors.initials: D
authors.lastname: Fowler
authors.affiliation: Clare Flach, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; Paul French, PhD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, Manchester, and Department of Psychological Sciences, Liverpool University, Liverpool; Graham Dunn, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; David Fowler, MSc, School of Psychology, University of Sussex, Brighton; Andrew I. Gumley, PhD, Institute of Health and Wellbeing, University of Glasgow, Glasgow; Max Birchwood, DSc, Division of Mental Health and Wellbeing, University of Warwick, Warwick; Suzanne L. K. Stewart, PhD, Department of Psychology, University of Chester, Chester; Anthony P. Morrison, ClinPsyD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, and School of Psychological Sciences, University of Manchester, Manchester, UK.
authors.forename: Andrew I
authors.initials: AI
authors.lastname: Gumley
authors.affiliation: Clare Flach, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; Paul French, PhD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, Manchester, and Department of Psychological Sciences, Liverpool University, Liverpool; Graham Dunn, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; David Fowler, MSc, School of Psychology, University of Sussex, Brighton; Andrew I. Gumley, PhD, Institute of Health and Wellbeing, University of Glasgow, Glasgow; Max Birchwood, DSc, Division of Mental Health and Wellbeing, University of Warwick, Warwick; Suzanne L. K. Stewart, PhD, Department of Psychology, University of Chester, Chester; Anthony P. Morrison, ClinPsyD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, and School of Psychological Sciences, University of Manchester, Manchester, UK.
authors.forename: Max
authors.initials: M
authors.lastname: Birchwood
authors.affiliation: Clare Flach, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; Paul French, PhD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, Manchester, and Department of Psychological Sciences, Liverpool University, Liverpool; Graham Dunn, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; David Fowler, MSc, School of Psychology, University of Sussex, Brighton; Andrew I. Gumley, PhD, Institute of Health and Wellbeing, University of Glasgow, Glasgow; Max Birchwood, DSc, Division of Mental Health and Wellbeing, University of Warwick, Warwick; Suzanne L. K. Stewart, PhD, Department of Psychology, University of Chester, Chester; Anthony P. Morrison, ClinPsyD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, and School of Psychological Sciences, University of Manchester, Manchester, UK.
authors.forename: Suzanne L K
authors.initials: SL
authors.lastname: Stewart
authors.affiliation: Clare Flach, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; Paul French, PhD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, Manchester, and Department of Psychological Sciences, Liverpool University, Liverpool; Graham Dunn, PhD, Centre for Biostatistics, Institute of Population Health, University of Manchester, Manchester; David Fowler, MSc, School of Psychology, University of Sussex, Brighton; Andrew I. Gumley, PhD, Institute of Health and Wellbeing, University of Glasgow, Glasgow; Max Birchwood, DSc, Division of Mental Health and Wellbeing, University of Warwick, Warwick; Suzanne L. K. Stewart, PhD, Department of Psychology, University of Chester, Chester; Anthony P. Morrison, ClinPsyD, Psychosis Research Unit, Greater Manchester West NHS Foundation Trust, and School of Psychological Sciences, University of Manchester, Manchester, UK.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Morrison
mesh_terms: D000293:Adolescent; D000328:Adult; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D011340:Problem Solving; D011597:Psychomotor Performance; D011618:Psychotic Disorders / Q000517:prevention & control*; D012307:Risk Factors; D016896:Treatment Outcome; D055815:Young Adult