Lithium treatment of mental disorders has been ušed for decades. Literary evidence about thyroid dysfunction induced by lithium is still contradictory. The aim of our study was to assess a possible negative influence of lithium treatment on thyroid gland function in a group of subjects with a mood disorder in comparison with the samé diagnostic group not treated with lithium. We selected all ICD-10 mood disorder patients who háve been using lithium for at least one year from the filé of the Dpt. of Psychiatry, University Hospital in Hradec Králové (n=108. average age 53.1±11.2 years, average length of lithium treatment 13.3±7.5 years, males n=44). The control group of ICD-10 mood disorder subjects without lithium (n=101, average age 50.2±14.6 years, males n=33) were chosen from the samé filé. We took venous blood samples of all patients to evaluate thyroid hormone levels. The TSH plasma levels were signiflcantly higher in the lithium patients as compared to the control subjects (4.59±9.19 vs. 2.36±2.00 mU/1, p<0.01, Kolmogorov-Smirnov test). The percentage of pathological TSH, T3 or T4 plasma levels during the lithium treatment as compared with other mood stabilizers was statistically signiflcant only in the subgroup of men (hyperthyroidism n=3 vs n=0, subclinical hypothyroi-dism n=3 vs n=0, p<0.05, Fishers test). Our findings support the hypothesis that long-term lithium treatment impaires thyroid gland function in accordance with the majority of literary data.

        Key words: mood disorder - lithium - hypothyroidism - hyperthyroidism