Despite the perceived importance of social cognition in determining social functioning outcomes for patients with schizophrenia, it has received limited attention in clinical trials. Furthermore, the impact of antipsychotic medication (which is the primary treatment for schizophrenia) on social cognition has not been thoroughly investigated, and existing studies lack consistent results.

A systematic review and research study were conducted to investigate the effects of antipsychotics on social cognition in patients with schizophrenia. The study recruited 73 patients with schizophrenia and 37 healthy volunteers, to take part in a social cognition assessment, as part of a sub-study of a larger-scale randomised controlled trial of antipsychotic reduction/discontinuation vs. maintenance.

Narrative results from the systematic review of sedative psychiatric medication effects on social cognition revealed diazepam impairs emotion processing in healthy volunteers. It also showed the extent to which studies of antipsychotics on social cognition have been limited by design. For the analysis in this thesis, cross-sectional results showed impaired social cognition in patients compared to healthy volunteers. Although, antipsychotic dose was not significantly related to any social cognition domain after controlling for confounders. The longitudinal results showed temporary dips in some social cognition domains and social functioning performance at 12- months after being in the antipsychotic reduction/discontinuation group, but improvements at 24 months, although the group x time interaction was only significant for the Theory of Mind domain.

Results from these studies should be interpreted with caution due to limitations including unequal group sizes, high attrition, and poor measure reliability. However, the results suggest that relationships between social cognition and antipsychotic reduction may exist, although the associations are complex and require more investigation. Further studies with larger sample sizes over long-term periods are needed, particularly in healthy volunteers, to establish relationships between variables.