Antithyroid antibodies in depressed patients

The presence of antithyroid (antimicrosomal and antithyroglobulin) antibodies was assessed in 45 psychiatric inpatients with prominent depressive symptoms (28 with DSM-III major depression). Nine patients (20%) had detectable titers of antithyroid antibodies, a rate considerably higher than the 5%-10% observed in the normal population. Each of these nine patients with symptomless autoimmune thyroiditis had normal baseline serum thyrotropin concentrations and normal thyroid function (as assessed by T4, T3 uptake, and free thyroxine index). These findings support the hypothesis of subtle thyroid dysfunction in a sizable sample of psychiatric inpatients with prominent depressive symptoms.