Antipsychotic medication-mediated cognitive change in schizophrenia and polygenic score for cognitive ability

Cognitive symptoms of schizophrenia are reported to be minimally responsive to treatment with antipsychotic medications, though variability exists and many prior studies have significant confounds. Here, we examined the response of cognitive symptoms to antipsychotic medications in 71 inpatients with schizophrenia on and off antipsychotic medications in a blinded, placebo-controlled, cross-over study design. Patients received either antipsychotic medication monotherapy or placebo for 4-6 weeks before switching conditions. Neuropsychological testing, including working memory, intelligence, episodic memory, and verbal fluency tests, was administered during each condition. Additionally, we assessed whether polygenic scores for cognitive ability (PGS_cog) related to variability in antipsychotic medication-induced changes in cognitive performance. Overall, significant changes in cognition were not observed in response to medications (p's > 0.05) except for in episodic memory (p = 0.01), which showed a medication-related improvement. Some antipsychotic medication-related cognitive changes were associated with genetic predisposition to cognitive ability: PGS_cog showed positive correlations with medication-induced improvements in verbal list learning (p = 0.02) and category fluency (p = 0.03). Our primary results reinforce the notion that in general, cognitive measures are minimally responsive to antipsychotic medication. However, PGS_cog results suggest that genetic variation may influence the ability of current treatments to affect cognitive change within this patient population. This study underscores the need for development of novel treatment options specifically targeting cognitive symptoms as well as the importance of genetic variability in treatment response for patients with schizophrenia.