Previous studies have provided evidence for Theory of Mind (ToM) impairment in bipolar disorder (BD). The aim of the study was to determine whether ToM impairment can be considered as a trait- marker or a state characteristic of BD.

ToM was assessed in 29 patients with bipolar-I during an episode and in remission as well as in 29 pair-matched for age, gender and education level healthy controls. Three different ToM tests were used (multilevel assessment): First Order False Belief Stories, Hinting Test, Faux Pas Recognition Test. Attention, memory, verbal learning ability, visuospatial ability, executive functions were also assessed using WAIS – Vocabulary, Block design, and Digit span, Stroop Test, Rey Auditory Verbal Learning Test, Trail Making Test, Wisconsin Card Sorting Test. Paired t-test was used to compare patients’ neuropsychological performance in episode and euthimic states and one-way ANOVA with post hoc Bonferroni corrections for the between groups comparisons.

Patients showed significant impairments on ToM tasks in the acute phase compared to the control group. ToM deficits did not persist beyond mood episode, except patients’ poor performance on Faux Pas. Dysfunction in verbal learning, working memory, visospatial ability was found during both the acute and the euthymic phases in relation to the comparison group. Poorer performance in attention, immediate verbal memory and executive function tasks was observed only in the acute phase of the illness.

Impairments in social cognition might reflect underlying general cognitive deficits and residual symptoms rather than representing a specific trait-marker in BD.