Objectives:
The aim of the study was to evaluate a relationship between concentrations of hoocysteine (HCY), vitamin B12 and folic acid and disturbances of cognitive functions during acute episode of bipolar depression.

Methods:
116 patients were studied (93 women, 23 men), aged 20-78 (mean 51±13) years during acute episode of bipolar depression. Depression was evaluated by the 17-item Hamilton’s Depression Rating Scale (HDRS). The following tests measuring cognitive functions were applied: Trail Making Test, Wisconsin Card Sorting Test, Stroop Test and Wechsler Adult Intelligence Scale–Revised. In all patients, the measurements of serum homocysteine, vitamin B12 and folic acid were carried out.

Results:
Hyperhomocystemia (HCY>15μM/l) was detected in 41 patients (35%), more frequently in men (52%) than in women (31%). Patients with hyperhomocysteinemia achieved worse results in sub-tests of WAIS-R (verbal understanding and perceptional organization). In men, negative correlation was found between HCY concentration and number of errors in Stroop Test, and WCST (total errors and non-perseverative errors). In women with bipolar disorder, type II, negative correlation between HCY concentration and time of Stroop Test, and between vitamin B12 concentration and number of errors in Stroop Test, were demonstrated. In the whole group and in men, there was positive correlation between higher folic acid concentration and the number of errors in Stroop Test.

Conclusions:
The results obtained show higher HCY concentration in considerable proportion of patients with bipolar depression, especially in men. They also confirm a connect between high homocysteine concentration and worse performance in some neuropsychological tests. Such relationship was more marked in men.