Six-year follow-up of thyroid function during lithium treatment.

A cohort of patients at various stages of lithium treatment was followed up for 6 years in order to evaluate the course of thyroid abnormalities. Ultrasonography confirmed that lithium can increase thyroid size, especially in cigarette smokers, and that it can affect the texture of the gland. However, the incidence of clinical hypothyroidism or specific thyroid autoimmunity does not exceed that found in the general population. Repeated determinations of thyrotrophin (TSH) concentrations can prevent clinically relevant consequences. Addition of carbamazepine to lithium can counteract lithium-induced subclinical hypothyroidism, possibly improving prophylactic efficacy in recurrent affective disorders.