Effectiveness of Cognitive Behavioral Therapies Targeting Cognitive Biases and Beliefs in Schizophrenia-Spectrum...

Cognitive models of schizophrenia-spectrum disorders (SSD) posit dysfunctional beliefs and cognitive biases as maintenance mechanisms of positive and negative symptoms. Although cognitive behavioral therapy (CBT) targets these processes, its effects on mechanism-level outcomes remain unclear. This review examined whether CBT modifies dysfunctional beliefs and cognitive biases in SSD using rigorous randomized evidence.

PRISMA 2020-compliant systematic review and meta-analysis (PROSPERO registered). Primary analyses were restricted to intention-to-treat (ITT) randomized controlled trials (RCTs) in SSD samples, using random-effects models and between-group post-treatment estimates. Pre-post and nonrandomized studies were analyzed separately as secondary evidence. Subgroup and meta-regression analyses were conducted.

Thirty-three studies met inclusion criteria. Fourteen ITT RCTs contributed to the primary pooled analysis of dysfunctional beliefs, yielding a small but statistically significant effect favoring CBT (g = 0.154, 95% CI, 0.049-0.259). Effects were strongest for delusional conviction (g = 0.450) and self-related schemas (positive-self g = 0.278; negative-self g = 0.298). Voice-related beliefs did not reach statistical significance. Too few RCTs assessed cognitive biases to support primary pooled analyses; exploratory findings suggested small effects for belief inflexibility and no reliable effect for jumping-to-conclusions. Greater reductions in dysfunctional beliefs were associated with greater improvements in positive symptoms across trials.

CBT produces small but reliable improvements in dysfunctional beliefs in SSD, although effects vary by domains particularly for delusional conviction and self-schemas, supporting their role as modifiable therapeutic targets and plausible mechanisms of change. Effects on cognitive biases remain limited and understudied.