The thyrotropin-releasing hormone test may predict recurrence of clinical depression within ten years after discharge.

Objectives: The underlying pathogenic mechanisms and predictors of recurrence in major depressive disorder are still largely unknown. Hypothalamic-pituitary-thyroid (HPT) axis and hypothalamus-pituitary-adrenocortical (HPA) axis dysregulation are thought to be related to the development and course of depression.

Design And Setting: Over a ten-year period, we investigated whether the results of thyrotropin-releasing hormone (TRH) testing and combined dexamethasone/corticotropin-releasing hormone (DEX/CRH) testing could be correlated with the recurrence of depression in 25 outpatients with clinically remitted major depression for at least 10 years.

Materials And Methods: Twenty-five patients (16 women and 9 men, 48.1 years of age, SD=11.4, range 22-84) with major depressive disorder were available for evaluation during hospitalization. TRH and DEX/CRH tests were administered at admission.

Results: Patients who recurred within ten years after remission exhibited significantly higher thyroid stimulating hormone (TSH) responses to TRH at the time of admission compared to those who did not recur. There was no significant correlation between recurrence and DEX/CRH levels after controlling for age, sex, and body mass index.

Conclusion: The findings of this study suggest that the TRH test may predict future recurrence in patients with depression.