Lithium is among the most effective therapies for bipolar disorder. Lithium treatment may cause hypothyroidism, goiter or to a lesser extent hyperthyroidism, since it can affect several aspects of thyroid functioning. The prevalence of lithium-associated hypothyroidism varies extensively between studies, reaching up to 47%, and affecting more females than males (5:1).

Determine the prevalence of thyroid dysfunction in an acute inpatient psychiatric department dedicated to affective disorders and its association with lithium therapy.

To review the relation between lithium treatment and thyroid dysfunction.

Observational, descriptive and retrospective study with clinical and laboratorial data concerning all inpatient episodes of 2015 in our Psychiatric Department. A non-systematic literature search was performed in PubMed.

The present study documented a high prevalence of thyroid dysfunction, particularly in women. Most cases were due to either hypothyroidism or subclinical hypothyroidism. Patients treated with lithium were more often under thyroid hormone replacement therapy (levothyroxine).

The evidence that lithium treatment is associated with hypothyroidism is well established and this condition is easily treatable with levothyroxine. This study highlights the importance of baseline screening of thyroid function and regular long-term monitoring in patients treated with lithium.

The authors have not supplied their declaration of competing interest.