Several studies have reported that Bipolar Disorder (BD) is characterized by neuropsychological deficits both during affective episodes and euthymic phases; in particular, bipolar patients (BPs) show psychomotor slowing and impairment of memory during Major Depressive Episodes and frontal-executive deficits in Hypomania.

The aim of the present study is to compare possible differences in cognitive performances of BPs during euthymia or during an affective episode.

22 BPs with an affective episode (depressive = 7, mixed = 7, manic = 8) and 5 euthymic patients underwent neuropsychological tests, after assessing the diagnosis by SCID-I. The cognitive abilities tested by raters included attention, verbal abilities, memory, abstract reasoning, executive functioning and semantic knowledge. One-way ANOVAs were performed on mean total scores of neuropsychological tests comparing euthymics versus BPs in the different phases of illness.

The 20% of euthymic patients showed attentive, verbal and memory deficits; the 40% showed perceptual and executive functioning deficits. Depressed (p = 0.03) and manic (p = 0.01) patients showed worse scores at Trail Making Test A (TMT-A) than euthymics. Manic patients presented the most severe deficits in memory as showed by the scores of Corsi's test (F = 4.96, p = 0.01), Recall of Prose (F = 4.06, p = 0.02) and California Verbal Learning Test (F = 3.67, p = 0.03).

Euthymic patients showed deficits in several cognitive domains. Manic patients had more severe deficits in attention and memory in comparison with depressed, mixed and euthymic patients. Controlled studies with larger samples are needed to confirm these data.