Most patients with hypothyroidism have some degree of associated depression, ranging from mild to severe. 10% – 15% of the patients with a diagnosis of depression may have thyroid hormone deficiency. Patients with depression should be tested to determine if they have a thyroid disorder.
- Several research studies have been done and continue to be done on the association between depression and thyroid disease. Although all forms of depression, including bipolar disorders like manic depression, can be found in either hypothyroidism or hyperthyroidism, depression is more often associated with hypothyroidism. Many patients with hypothyroidism have some degree of associated depression, ranging from mild to severe.
- If a large population of depressed patients was screened, a significant percentage, perhaps 10% – 15%, would be found to have thyroid hormone deficiency. For this reason, patients with a diagnosis of depression should be tested to determine if they have too little thyroid hormone. If they do, thyroid medication should be prescribed.
- Thyroid hormone is sometimes prescribed for depressed patients with normal thyroid function because it magnifies the beneficial effects of certain antidepressants.
- Lithium, a commonly prescribed drug for certain types of depression, has profound effects on the size and function of the thyroid gland. Patients taking lithium need periodic examinations of their thyroid gland and thyroid function.