The thyroid and melancholia.

Several studies that have examined heterogeneous groups of patients suggest that altered thyroid function may distinguish melancholic from nonmelancholic depression. We therefore measured basal thyroid hormone levels in 90 unipolar depressed patients who were divided into melancholic and nonmelancholic subgroups according to three definitions. Levels of thyroxine, triiodothyronine, and thyrotropin, obtained using an ultrasensitive assay, did not distinguish the subtypes of depression. However, severity of depression contributed significantly to the difference between these subtypes according to DSM-III and Research Diagnostic Criteria.