Interrelationships of Changes in Outcome Domains in Patients With Schizophrenia Spectrum Disorders: A Meta-Analysis

Introduction: Patients with schizophrenia spectrum disorders (SSD) improve in several outcome domains over the course of illness, but to different degrees. In this meta-analysis, we investigated whether longitudinal changes in different outcome domains are associated with each other and which factors moderate these changes over time. Methods: Our protocol was preregistered in PROSPERO (CRD42024504253). We included 109 studies, identified through searches in PsycInfo, PubMed, CINAHL, and Cochrane up until November 2023, investigating longitudinal changes in at least two outcome domains (symptoms, social functioning, cognition or personal recovery) for patients with SSD with at least 1 year follow-up. We calculated Pearson correlation coefficients for associations of changes between outcome domains. Potential moderating effects of demographic, clinical, social, or study characteristics were explored. Quality assessment was executed using the QUIPS tool. Results: We found substantial positive associations between changes in symptoms, social functioning, and cognition. Especially, changes in negative symptoms and overall social functioning were associated with changes in several outcome domains. Changes in personal recovery were only associated with changes in symptoms. We found more substantial improvements in combinations of outcomes for patients with a shorter illness duration, females, a lower percentage of patients diagnosed with schizophrenia, and patients receiving treatment focused on targeted outcomes. Conclusions: Symptoms, social functioning, and cognition often concurrently improve and may boost each other. This suggests that an integrated approach targeting several outcome domains jointly boosts long-term improvement. However, changes in personal recovery seem to occur separately from other outcome domains. Therefore, targeted attention for personal recovery is needed. Trial Registration: PROSPERO: CRD42024504253.