The Effects of Cognitive Remediation on Negative Symptoms in Schizophrenia-Spectrum Illness: A Meta-analytic Investigation of Efficacy.

Background and hypothesis: The number of clinical efficacy trials of Cognitive Remediation (CR), a behavioral intervention consisting of cognitive task practice and/or strategy training to improve cognitive skills in schizophrenia, has increased substantially over the past 25 years. While recent reviews have highlighted the effects of CR on cognition and function, CR effects on negative symptoms remain understudied. Given the overlap between negative symptoms and cognition, CR effects might be expected.

Study design: Electronic databases were evaluated up to September 2023 using a broad range of search terms. Sixty-nine unique, controlled trials that used negative symptoms as an outcome were meta-analyzed. Data were independently extracted with excellent (>98%) reliability. Random effects models assessed the effects of CR on summary and expressive vs. experiential negative symptoms. Moderator analyses evaluated a broad array of treatment and participant factors.

Study results: The meta-analysis (5319 participants) revealed that CR produced a small effect size improvement on summary negative symptoms (Hedge's g = 0.179). Sample differences in age, duration of illness, symptoms, and antipsychotic dosage did not serve as a barrier to treatment benefit. CR also produced small-to-moderate improvements in alogia (Hedge's g = 0.312) but not experiential negative symptoms. Programs of CR that utilized bridging activities that relate training of cognitive skills to activities of daily living produced greater improvement in negative symptoms (g = 0.281 vs 0.055). Longer CR programs also produce larger effects on negative symptoms.

Conclusions: CR produces small, consistent reductions in negative symptoms in people with schizophrenia. Variations in CR effects may be linked to different treatment ingredients.