Lithium therapy and thyroid function: a long-term study.

Seventy-three patients who had been continuously receiving lithium carbonate for 6 months or more had their thyroid function evaluated clinically and biochemically. Goitre was found in 37%, exophthalmos in 23%, positive thyroid auto-antibodies in 24% and abnormal TRH tests in 49%. It would appear that thyroid failure due to lithium is usually dependent on antibody mediated damage. It is unlikely that lithium has a direct effect on the hypothalamic-pituitary axis.