Serum levels of second-generation antipsychotics are associated with cognitive function in psychotic disorders

Abstract Objectives: Antipsychotics are effective in treating psychosis and mood episodes; however, the effect on cognition is less known. We investigated the association between serum levels of second-generation antipsychotics (SGAs) and cognitive performance in psychosis spectrum disorders in a naturalistic setting. Methods: A total of 495 patients with a DSM-IV Schizophrenia and Other Psychotic Disorders (SCZ, n = 373) or Bipolar Disorder (BD, n = 122) diagnosis treated with olanzapine, quetiapine, aripiprazole or risperidone were tested neuropsychologically with concurrent measurement of the serum concentration of the drug. Linear regression was used for association analyses. Results: Attention was positively associated with the olanzapine concentration (standardised beta (β) coefficient = 0.19, P = .006), and short-term verbal memory and verbal fluency were negatively associated with the quetiapine (β = –0.24, P = .004) and risperidone (β = –0.37, P = .007) concentrations respectively. Conclusions: The present results suggest that SGA serum concentration is associated with better attention (small effect size), and worse verbal memory (small effect size) and verbal fluency (medium effect size). These findings are in line with the notion that SGAs affect aspects of cognitive function, and suggest careful dosing in patients with severe memory and executive problems.