Discrepancy between subjective and objective severity in treatment-resistant depression: prediction of treatment outcome.

OBJECTIVE: Identifying predictors of outcome among patients with treatment-resistant depression (TRD) is challenging. We hypothesised that discrepancy between self-rated and observer-rated scales may be a simple way of making such a prediction.
METHOD: 102 patients were admitted to a unit specialising in the treatment of resistant depression and underwent fortnightly assessment with clinician-rated (Hamilton Depression Rating Scale-21, HAM-D) and self-rated (Beck Depression Inventory, BDI) measures. All patients had significant depressive symptoms that were treatment resistant, 70% as part of a major depressive disorder and the remainder as part of a bipolar or other disorder. A discrepancy score between the HAM-D and BDI was calculated on admission and its association with patient clinico-demographic factors was determined. A subset of 67 patients remained as inpatients for 40 weeks or until clinical response and were entered into a responder analysis, in which response was defined as ≥50% reduction in admission HAM-D score. The association of the admission BDI-HAM-D discrepancy score with subsequent patient response, was determined.
RESULTS: The magnitude of BDI-HAM-D discrepancy was higher in those with co-morbid personality disorder, lower in those with psychosis and positively correlated with anxiety. High BDI-HAM-D discrepancy score predicted delayed treatment response (odds ratio 5.40, p = 0.005).
CONCLUSION: Within TRD, higher discrepancy predicts slower response to treatment independent of objective illness severity; this may be mediated by underlying personality traits and co-morbid anxiety.