Neurocognitive functions in euthymic bipolar patients

Meta-analytic findings support the hypothesis of specific neurocognitive deficits for bipolar patients in the domains of attention, processing speed, memory and executive functions. This study aims to show neurocognitive impairment in euthymic patients with bipolar I disorder compared with healthy controls while detailing the impact of medication side-effects or illness characteristics on neuropsychological test performance. Forty euthymic patients with bipolar I disorder were compared with 40 healthy controls in a cross-sectional design. Clinical features and neuropsychological measures of IQ, psychomotor speed, verbal fluency, learning and memory, executive functions and attention were assessed. Patients without antipsychotic drug use did not differ significantly from healthy controls in any neuropsychological measure. Yet patients treated with antipsychotics showed significant underperformance in the domains of semantic fluency, verbal learning and recognition memory as well as executive functions related to planning abilities, even when clinical features were controlled for. The impact of antipsychotic medication needs to be further clarified for euthymic bipolar patients and should be considered when neuropsychological test performance is interpreted.