Relationship between atypical antipsychotic treatment and neurocognitive functions in bipolar disorder

Objective: The number of studies focusing on the effects of individual psychotropic medications on cognition in bipolar disorder is limitied. Little is known about the neurocognitive effects of atypical antipsychotics in this illness. The aim of this study was to compare neurocognitive performance in euthymic patients with bipolar disorder receiving maintenance treatment with mood stabilizer alone (MS), and atypical antipsychotics as adjunctive to MS (MS+AA) in comparison to healthy controls (HC). Methods: Neurocognitive performance was assessesed in executive functioning, attention and processing speed, verbal and visual memory, and verbal fluency domains in patients who were euthymic for at least four weeks and receiving either MS monotherapy ( n=36), or MS+AA combination (n=46) in comparison to healthy controls (n=55) Non-parametric comparison and correlation tests were used for continious variables whereas categorical variables were compared using Chi-square analysis. Results: patient groups performed poorly then HC, the patients receiving MS+AA performed poorest on most neurocognitive measures. Two patient groups performed poorly on executive functions, visiual memory, attention and processing speed than HC. Patients receiving MS+AA had impaired performance also on psychomotor speed, verbal and semantic fluency and response inhibition than HC. After several head to head group comparisons the patients receiving adjunctive ketiyapin showed a better performance than patients receiving adjunctive olanzapin as AA. Conclusion: Although randomized controlled trials are required to confirm the cognitive side effects of medications prescribed for maintenance treatment of bipolar disorder, our results indicate that addition AA to a MS has a negative impact on cognitive performance. Quetiapine seemed to be less associated with impairment on neurocognitive measures.