Social cognition in euthymic bipolar disorder: systematic review and meta-analytic approach

Objective: Deficits in social cognition have been reported in euthymic subjects with bipolar disorder (BD). However, some studies have failed to find differences favoring controls. As most investigations have been conducted with small samples, they have not had sufficient power to detect statistically significant differences. Furthermore, studies communicating positive results have scarcely attempted to estimate effect sizes for patient-control differences. The aim of this study was to summarize the findings of reports on social cognition in patients with euthymic BD and to combine their data to identify possible deficits and quantify their magnitude. Method: Systematic literature review and meta-analysis. Results: Impairments of moderate magnitude (0.5 < d < 0.8) were noted across mentalizing skills, whereas small but significant effect sizes (d < 0.5) were observed for facial emotion recognition. No patient-control differences were found for decision-making. Conclusion: Meta-analytic findings provide evidence for emotion processing and theory of mind deficits in remitted bipolar patients. However, it is not yet clear whether these areas of impairment are related to neurocognitive dysfunctions or to medication effects. The results are discussed with regard to targets for future neuropsychological research on BDs.