Plasma norepinephrine and prediction of outcome in major depressive disorder

Background: Several epidemiologic and clinical factors have been shown to predict long term outcome in major depressive disorder (MDD). The value of biological predictors has not been extensively studied. This study examined whether plasma norepinephrine may be useful in predicting outcome in MDD. Methods: Forty patients were followed up 8 years after an index major depressive episode. Three outcome variables were assessed: time to first recurrence (the primary outcome measure), the Lee and Murray criteria and the Depression Outcome Scale (DOS). The results were examined against plasma norepinephrine value, at the index episode, using survival analysis and linear regression. Results: High plasma norepinephrine at the index episode was positively and significantly associated with time to first recurrence for patients with nonpsychotic MDD (n = 31, χ2 = 8.38, on 1 df, p< .01). Similarly, plasma norepinephrine was significantly associated with good global outcome, both using Lee and Murray criteria (n = 34, adjusted R2 = .24, p< .01) and DOS criteria (n = 31, adjusted R2 = .17, p< .01) for this group of patients. In contrast, plasma norepinephrine was not significantly related to outcome for MDD with psychotic features. Conclusions: Plasma norepinephrine at index episode seems to be a predictor of outcome in MDD.