Cognitive Behavioural Therapy (CBT) for schizophrenia : a meta-analysis

Background: Despite the effectiveness of pharmacotherapy for the treatment of schizophrenia, up to 60% continue to experience distressing symptoms such as hallucinations or delusions. Adjunctive cognitive behavioural therapy (CBT) is now recommended in many countries. There has been some debate as to whether CBT is effective in reducing the symptoms of schizophrenia. Meta-analyses to date have shown varying results. The aim of this meta-analysis was to examine moderating effects of a) study/trial quality, b) comprehensiveness of the CBT intervention, c) manualized vs. non manualized treatments, d) control group, e) chronicity of presentations of schizophrenia, and f) format of treatment. Method: A systematic search of the literature was conducted in PsychInfo, Scopus, Embase and Medline to identify randomized controlled trials reporting on the impact of CBT on positive, negative, global psychopathology and total symptoms and a random-effects meta-analysis was performed. Results: 23 studies including 2,639 participants published between 1990 and 2015 were identified. Small and largely non-significant effect sizes were found at post-treatment for total symptoms (g=0.19), negative symptoms (g= 0.12) and global psychopathology (g=0.12), with a significant but small effect size found for the reduction of positive symptoms (g=0.19). Moderators had little impact overall, with no consistent evidence of quality, comprehensiveness, manualisation, control group, stage of illness or format of treatment moderating effect size for any symptom type. The clinical implications for the use of CBT with this population are discussed.