Associations among dexamethasone non-suppression and TRH-induced hormonal responses: increased specificity for melancholia?

TRH-induced thyrotropin (TSH), prolactin (PRL), and growth hormone (GH) responses were investigated together with a dexamethasone suppression test in female psychiatric inpatients with major melancholic depression (n = 21), schizophrenic disorder (n = 20), alcohol dependence (n = 11), and adjustment disorder with predominantly depressed mood (n = 13), as well as in 15 healthy women. Abnormal responses for all four endocrine variables were noted most frequently in melancholia; however, a significant number of the non-depressed patients also had abnormal hormonal responses in the individual test. The association of two or three abnormalities proved to be quite specific for the melancholic group. There were no statistically significant differences in TRH-induced TSH responses among the patient subgroups. Non-suppression of cortisol after dexamethasone was associated with blunted TSH-responses only in melancholia. There was a tendency for non-suppressor schizophrenics to show more abnormal GH-responses to TRH administration.