Measuring the severity of depression and remission in primary care: validation of the HAMD-7 scale

Background: Symptomatic remission is the optimal outcome in depression. A brief, validated tool for symptom measurement that can indicate when remission has occurred in mental health and primary care settings is unavailable. We evaluated a 7-item abbreviated version (HAMD-7) of the 17-item Hamilton Depression Rating Scale (HAMD-17) in a randomized controlled clinical trial of patients with major depressive disorder being cared for in primary care settings. Methods: We enrolled 454 patients across 47 primary care settings who met DSM-IV-TR criteria for a major depressive disorder. Of these, 410 patients requiring antidepressant medication were randomized to have their symptoms rated with either HAMD-7 (n = 205) or HAMD-17 (n = 205) as the primary measurement tool. The primary outcome was the proportion of patients who achieved a-priori defined responses to 8 weeks of therapy using each instrument. Results: Of the 205 participants per group, 67% of those evaluated with HAMD-7 were classified as having responded to therapy (defined as a 50% reduction from the pretreatment score), compared with 74% of those evaluated with HAMD-17 (p = 0.43). The difference between the groups' changes in scores from baseline ( pretreatment) to endpoint was significant (p < 0.001), without a main effect of group (p = 0.84) or group-by-time (p = 0.83) interaction. The HAMD-7 test was brief to administer (e. g., 3-4 min for 85% of the primary care physicians evaluated), which facilitated the efficient and structured evaluation of salient depressive symptoms. Interpretation: The abbreviated HAMD-7 depression scale is equivalent to the HAMD-17 in assessing remission in patients with a major depressive disorder undergoing drug therapy.