The course of thyroid abnormalities during lithium treatment: a two-year follow-up study.

A total of 116 patients on lithium treatment were followed up for 2 years to determine the course and the clinical relevance of thyroid abnormalities. Elevated thyroid-stimulating hormone (TSH) concentrations were transitory in most patients, except those with serum antithyroid antibodies. The patients who initially had microsomal antibodies remained positive, with an increase in titre in two-thirds of cases. Three young patients of both sexes developed thyroid autoimmunity early in the treatment. The risk of developing hypothyroidism was higher in women, especially in the presence of antibodies. TSH concentrations were significantly lower when carbamazepine was combined with lithium.