Psychol Med. 2022 Aug 18:1-11. doi: 10.1017/S0033291722002409. Online ahead of print.
BACKGROUND: Schizophrenia (SZ) is a complex brain disorder linked to cognitive and neurostructural abnormalities that involves genetic and environmental factors with obstetric complications (OCs) at birth conferring a high risk for the disease. Indeed, current research in the general population describes the deleterious effect of OCs on cognitive performance in adulthood. With this rationale, we aim to review the relationship between OCs and cognition in SZ and related psychotic disorders.
METHODS: A systematic review and meta-analysis describing cognitive function and OCs in patients with SZ and related disorders were conducted. PubMed, EmBase, SCOPUS, and the Cochrane Library were systematically searched to identify eligible studies up to January 2022. We calculated the effect sizes (Hedges’ g) of cognitive domains within each study and quantified the proportion of between-study variability using the I2 statistic. Homogeneity was assessed using the Q-statistic (X2). The study was registered on PROSPERO (CRD42018094238).
RESULTS: A total of 4124 studies were retrieved, with 10 studies meeting inclusion criteria for the systematic review and eight for meta-analysis. SZ subjects with OCs showed poor verbal memory [Hedges’ g = -0.89 (95% CI -1.41 to -0.37), p < 0.001] and working memory performance [Hedges’ g = -1.47 (95% CI -2.89 to -0.06), p = 0.01] in a random-effect model compared to those without OCs.
CONCLUSIONS: OCs appear to have a moderate impact on specific cognitive such as working memory and verbal memory. Our findings suggest that OCs are associated with brain development and might underlie the cognitive abnormalities described at onset of psychosis.