Clinical Characteristics of Patients with Major Depressive Disorder with and without Hypothyroidism: A Comparative Study

Introduction. Differentiating major depressive disorder (MDD) without hypothyroidism from MDD associated with hypothyroidism can be challenging. Therefore some authors have suggested that thyroid function should be tested in all depressed patients. This study compared the clinical characteristics of patients with MDD associated with hypothyroidism with those of patients with MDD without hypothyroidism. Method. Thyroid function tests were administered to 75 patients (60 female and 15 male) who met DSM-IV criteria for MDD. The 15 patients with hypothyroidism (8 with subclinical hypothyroidism and 7 with overt hypothyroidism) were compared with the other 60 patients with regard to depressive characteristics. The primary measure of depressive signs and symptoms used to assess depression severity and symptoms was the Hamilton Rating Scale for Depression, first 17 items (Ham-D-17). Baseline demographic data, including age and sex, were also compared. Result. The two groups did not differ significantly in severity of overall depression at baseline, as measured by total score on the Ham-D-17 (p = 0.471, Z = 0.970). Patients with MDD without hypothyroidism had worse scores on item 1 (depressed mood), item 2 (feelings of guilt), item 3 (suicidality), item 6 (late insomnia), and item 16 (loss of weight). In contrast, depressed patients with hypothyroidism had more severe anxiety symptoms and greater agitation (items 9, 10, and 11). Conclusion. Our results may help clinicians differentiate MDD associated with hypothyroidism from MDD without hypothyroidism. Depressed patients with hypothyroidism had more anxiety symptoms and greater agitation, but they had fewer severe core depressive symptoms and biological signs of MDD. (Journal of Psychiatric Practice 2011;17:67-71)