What potential side effect is associated with the use of lithium in treating bipolar disorder?

Lithium is a commonly used mood stabilizer for the treatment of bipolar disorder, and one of its significant side effects is thyroid dysfunction. Long-term use of lithium can lead to alterations in thyroid hormone levels, particularly causing hypothyroidism. This occurs because lithium interferes with the ability of the thyroid gland to produce adequate amounts of thyroid hormones, which are essential for regulating metabolism and overall energy levels in the body.

Monitoring thyroid function is important for individuals on lithium, as the development of hypothyroidism can lead to symptoms such as fatigue, weight gain, and depression, potentially complicating the management of bipolar disorder. Therefore, understanding the relationship between lithium and thyroid health is vital for those treating patients with this medication.