title: The long-term effectiveness of cognitive behavior therapy for psychosis within a routine psychological therapies service.
abstract: Randomised controlled trials (RCTs) have shown the efficacy of CBTp, however, few studies have considered its long-term effectiveness in routine services. This study reports the outcomes of clients seen in a psychological therapies clinic, set up following positive results obtained from an RCT (Peters et al., 2010). The aims were to evaluate the effectiveness of CBTp, using data from the service's routine assessments for consecutive referrals over a 12 years period, and assess whether gains were maintained at a 6+ months' follow-up. Of the 476 consenting referrals, all clients (N = 358) who received ≥5 therapy sessions were offered an assessment at four time points (baseline, pre-, mid-, and end of therapy) on measures assessing current psychosis symptoms, emotional problems, general well-being and life satisfaction. A sub-set (N = 113) was assessed at a median of 12 months after finishing therapy. Following the waiting list (median of 3 months) clients received individualized, formulation-based CBTp for a median number of 19 sessions from 121 therapists with a range of experience receiving regular supervision. Clients showed no meaningful change on any measure while on the waiting list (Cohen's d <= 0.23). In contrast, highly significant improvements following therapy, all of which were significantly greater than changes during the waiting list, were found on all domains assessed (Cohen's d: 0.44-0.75). All gains were maintained at follow-up (Cohen's d: 0.29-0.82), with little change between end of therapy and follow-up (Cohen's d <= 0.18). Drop-out rate from therapy was low (13%). These results demonstrate the positive and potentially enduring impact of psychological therapy on a range of meaningful outcomes for clients with psychosis. The follow-up assessments were conducted on only a sub-set, which may not generalize to the full sample. Nevertheless this study is the largest of its kind in psychosis, and has important implications for the practice of CBTp in clinical services.
authors.affiliation: Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK ; Psychological Interventions Clinic for Outpatients with Psychosis, South London and Maudsley NHS Trust London, UK ; NIHR Biomedical Research Centre for Mental Health, South London and Maudsley NHS Trust, King's College London London, UK.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Peters
authors.affiliation: Psychological Interventions Clinic for Outpatients with Psychosis, South London and Maudsley NHS Trust London, UK.
authors.forename: Tessa
authors.initials: T
authors.lastname: Crombie
authors.affiliation: Department of Biostatistics, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK.
authors.forename: Deborah
authors.initials: D
authors.lastname: Agbedjro
authors.affiliation: Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK ; Psychological Interventions Clinic for Outpatients with Psychosis, South London and Maudsley NHS Trust London, UK.
authors.forename: Louise C
authors.initials: LC
authors.lastname: Johns
authors.affiliation: Department of Biostatistics, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Stahl
authors.affiliation: Department of Psychology, Sussex University Sussex, UK ; Sussex Partnership NHS Foundation Trust Sussex, UK.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Greenwood
authors.affiliation: Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK ; Psychological Interventions Clinic for Outpatients with Psychosis, South London and Maudsley NHS Trust London, UK.
authors.forename: Nadine
authors.initials: N
authors.lastname: Keen
authors.affiliation: Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK ; Psychological Interventions Clinic for Outpatients with Psychosis, South London and Maudsley NHS Trust London, UK.
authors.forename: Juliana
authors.initials: J
authors.lastname: Onwumere
authors.affiliation: Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK ; Psychological Interventions Clinic for Outpatients with Psychosis, South London and Maudsley NHS Trust London, UK.
authors.forename: Elaine
authors.initials: E
authors.lastname: Hunter
authors.affiliation: Psychological Interventions Clinic for Outpatients with Psychosis, South London and Maudsley NHS Trust London, UK.
authors.forename: Laura
authors.initials: L
authors.lastname: Smith
authors.affiliation: Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK ; Psychological Interventions Clinic for Outpatients with Psychosis, South London and Maudsley NHS Trust London, UK ; NIHR Biomedical Research Centre for Mental Health, South London and Maudsley NHS Trust, King's College London London, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Kuipers
keywords: cognitive behaviour therapy; effectiveness; psychosis; randomised controlled trials; schizophrenia