Thyroid disorders in lithium-treated patients.

BACKGROUND

Little is known about the rate of thyroid disorders prior to lithium treatment, and which patients have a higher risk for developing such disorders during such treatment.

METHOD

Assessment of the thyroid histories and laboratory results of 209 lithium-treated patients with affective disorders from one catchment area.

RESULTS

Six female patients had thyrotoxicosis before starting lithium, a rate of 4.9%. Twenty patients developed hypothyroidism during the treatment: 3.4% of all males and 14.9% of all females. Female patients over the age of 50 were more likely to develop early lithium-induced hypothyroidism.

CONCLUSIONS

(1) Female patients with affective disorders might have an increased rate of thyrotoxicosis. (2) Lithium-induced hypothyroidism might develop earlier in female patients over the age of 50.

LIMITATIONS

Retrospective design of the study.

CLINICAL RELEVANCE

(1) The thyroid status of patients with affective disorders might be more relevant than is appreciated. (2) Guidelines for thyroid tests in lithium-treated patients should reflect the different risks conferred by age and gender.