Background: Studies attempting to identify predictors of antidepressant response in patients with major depression have reported inconsistent results. One explanation may be the different definitions of outcome used.
Methods: 187 depressed subjects were recruited and were randomised to treatment with fluoxetine and nortriptyline. At baseline and 6 weeks, subjects completed Hamilton Depression Rating Scale HDRS-17 and 27, Montgomery Asberg Depression Rating Scale (MADRS), the Hopkins Symptom Checklist (SCL-90) and the Social Adjustment Scale (SAS) as well as the Clinical Global Impression Scale (CGI). Relationships among outcome measures were assessed. Receiver Operator Characteristic (ROC curves) were used to show the diagnostic ability of the MADRS and HDRS in predicting the clinician's rating.
Results: All outcome measures were moderately to highly correlated. All measures were significantly related to the clinician's global impression, but the strongest associations were with the MADRS score. Using ROC curves we showed that a score of 8 on the HDRS or 14 on the MADRS was the optimal compromise between sensitivity and specificity in dividing this sample into responders and non-responders. A 60% reduction in HDRS and MADRS scores rather than a 50% reduction appeared the most valid division between responders and non-responders.
Limitations: We relied on clinician judgement as the validating criterion. The results only apply to a sample of moderately depressed outpatients.
Conclusions: The MADRS score seemed to most accurately reflect a clinician's impression of change. Dividing a sample into responders and non-responders can be approached empirically.