The thyrotropin-releasing hormone and dexamethasone suppression tests in the familial classification of depression.

Eighty-eight depressed patients who had received a dexamethasone suppression test (DST) and thyrotropin-releasing hormone (TRH) test were divided into four subgroups based on family history of psychiatric illness. Nonsuppression on the DST was found in 46% of familial pure depressive disease (FPDD) patients, 38% of sporadic depressive disease (SDD) patients, 38% of depressive spectrum disease (DSD) patients, and 50% of mixed depressive disease patients (patients with both a first degree relative with alcoholism and one with depression). A blunted thyroid-stimulating hormone response to TRH was found in 50% of FPDD patients, 56% of SDD patients, 47% of DSD patients, and 56% of mixed depressive disease patients. Neither the DST nor TRH test was found to distinguish significantly among the four familial subgroups of depression.