Thyroid abnormalities during lithium treatment.

Thyroid function was evaluated in 150 Sardinian outpatients at different stages of lithium treatment. A visible and/or palpable goitre was found in 51% of patients, and there was no apparent correlation with the duration of treatment. No cases of symptomatic hypothyroidism were observed, but subclinical hypothyroidism was present in 19% of patients. The prevalence of specific antithyroid antibodies was positively correlated with age and duration of lithium treatment, and was higher in women. Subclinical hypothyroidism was observed in 53% of antibody-positive lithium-treated patients. Carbamazepine in combination with lithium was associated with significantly lower levels of total T4 and T3 than with lithium alone, and the ratios between total and free hormones were also decreased.