A systematic review of moderators of cognitive remediation response for people with schizophrenia

Background There is evidence that cognitive remediation (CR) is moderately effective in improving cognitive and functional difficulties in people with schizophrenia. However, there is still a limited understanding of what influence different treatment responses. Aim To identify moderators influencing CR response in people with schizophrenia. Methods This systematic review follows PRISMA guidelines. Searches were conducted up to January 2019 on PubMed and PsychInfo to identify randomized controlled trials of CR reporting analyses of moderators of treatment response. All papers were assessed for methodological quality and information on sample size, intervention and control condition, moderators, outcomes, effect of moderator on outcomes and demographic characteristics from each study was extracted and critically summarised. Results Thirty-six studies were included, considering 2737 participants. Study participants consisted on average of people in their late-thirties, mostly men, with over 10 years of illness. The review identified moderators that could be grouped into five categories: demographics, biological, cognitive and functional, psychological, and illness-related characteristics. The assessment of methodological quality showed that many studies had a high risk of bias. Conclusions There was no high-quality replicated evidence which identifies reliable moderators of CR response. Many moderators were not replicated or presented in single, underpowered studies. Studies also investigated moderators independently despite their potential to overlap (e.g. age and education). Future research should concentrate on evaluating, with sound studies, the role moderators may play in affecting CR treatment response. This information can inform who will benefit most from the therapy and help to improve the benefits of CR.