Cognitive Behavior Therapy for Schizophrenia: Effect Sizes, Clinical Models, and Methodological Rigor

Abstract

Background: Guidance in the United States and United Kingdom has included cognitive behavior therapy for psychosis (CBTp) as a preferred therapy. But recent advances have widened the CBTp targets to other symptoms and have different methods of provision, eg, in groups. Aim: To explore the effect sizes of current CBTp trials including targeted and nontargeted symptoms, modes of action, and effect of methodological rigor. Method: Thirty-four CBTp trials with data in the public domain were used as source data for a meta-analysis and investigation of the effects of trial methodology using the Clinical Trial Assessment Measure (CTAM). Results: There were overall beneficial effects for the target symptom (33 studies; effect size = 0.400 [95% confidence interval {CI} = 0.252, 0.548]) as well as significant effects for positive symptoms (32 studies), negative symptoms (23 studies), functioning (15 studies), mood (13 studies), and social anxiety (2 studies) with effects ranging from 0.35 to 0.44. However, there was no effect on hopelessness. Improvements in one domain were correlated with improvements in others. Trials in which raters were aware of group allocation had an inflated effect size of approximately 50%–100%. But rigorous CBTp studies showed benefit (estimated effect size = 0.223; 95% CI = 0.017, 0.428) although the lower end of the CI should be noted. Secondary outcomes (eg, negative symptoms) were also affected such that in the group of methodologically adequate studies the effect sizes were not significant. Conclusions: As in other meta-analyses, CBTp had beneficial effect on positive symptoms. However, psychological treatment trials that make no attempt to mask the group allocation are likely to have inflated effect sizes. Evidence considered for psychological treatment guidance should take into account specific methodological detail.

A feasibility study of Acceptance and Commitment Therapy for emotional dysfunction following psychosis

“…In the ACT arm of the current study, a significant association was found between changes in depression and changes in mindfulness skills. To date methodologically rigorous research has failed to evidence the effectiveness of CBTp for treating depression in psychosis (Wykes et al, 2008). This is all the more concerning in light of Saarni et al's (2010) finding that depressive symptoms are the strongest predictors of poor quality of life in psychotic disorders.…”

“…Randomised clinical trials have found that Cognitive Behaviour Therapy for psychosis (CBTp) is efficacious for treating residual distressing positive and negative symptoms (Wykes et al, 2008). However, the evidence for treating emotional dysfunction (such as anxiety, depression and hopelessness) is less clear (Birchwood, 2003).…”

“…However, the evidence for treating emotional dysfunction (such as anxiety, depression and hopelessness) is less clear (Birchwood, 2003). Although, Wykes et al (2008) found a moderately strong effect size of CBTp on mood, when studies with 'poor' methodological quality were controlled for, the weighted effect size on mood in the adequate quality studies was not significant.…”

Randomized Controlled Trial of Cognitive Behavioral Social Skills Training for Older Consumers With Schizophrenia: Defeatist Performance Attitudes and Functional Outcome

“…A meta-analysis of 35 CBT clinical trials (9) recently showed that, although the vast majority of studies focused on positive symptoms as the primary treatment target, CBT also had beneficial impact on functioning. Fifteen of the studies reviewed included functioning measures and the average effect size for improvement in functioning ( d =0.38) and negative symptoms ( d =0.44) was comparable to that for positive symptoms ( d =0.37).…”

Cognitive–behavioural therapy for patients with schizophrenia: a multicentre randomized controlled trial in Beijing, China

“…P. Morrison et al 2011;Rathod et al 2008;Tarrier et al 2004). Certain psychosocial treatments, such as cognitive behaviour therapy (CBT) , have been shown to have a beneficial effect on positive and negative symptoms, mood, social functioning and social anxiety and is effective in reducing readmissions to hospital, duration of admission and symptom severity (Lysaker et al 2010), (Wykes et al 2008). CBT therefore addresses the limitations of medication- (Kreyenbuhl et al 2010).…”