Original article
Deficit of executive functions in the offspring of patients with bipolar affective illness

Background: Patients with bipolar affective illness present disturbances of executive functions which are observed also during euthymia period. It has been found that a deficit of these functions can also occur in their offspring. The aim of this study was an assessing of executive functions measured by means of the Wisconsin Card Sorting Test (WCST), in children of patients with bipolar affective illness compared to control group of healthy persons carefully age- and gender matched with experimental group.

Material and methods: Fifty persons (33 female, 17 male), aged 18-52 (30 ±7) years made the total adult offspring population of patients with bipolar affective illness. Among them, two had a history of depressive episodes, and another eight scored positively on Mood Disorder Questionnaire. The head-to-head age- and gender-matched healthy subjects were used as a comparison group. The computer version of WCST was used measuring the following domains of WCST: the percentage of perseverative errors (WCST-P), the percentage of non-perseverative errors (WCST-NP), the number of correctly completed categories (WCST-CC), the percentage of conceptual level responses (WCST-%conc), and the set to the first category (WCST-1st cat).

Results: The results of WCST in the total bipolar offspring group were inferior compared to matched control group. This was significant in the categories of perseverative errors (WCST-P) and conceptual responses (WCST-%conc) where the differences remained significant after Bonferroni correction. The offspring showing some affective morbidity (n = 10) did not show differences with forty healthy children.

Conclusions: The results of our study show the impairment of executive functions, connected with prefrontal cortex activity (especially WCST-P and WCST-%conc), in healthy offspring of bipolar patients. This may suggest that the disturbances of these functions could make a cognitive endophenotype of this illness.