There is a pressing need to develop effective treatments for individuals with major depressive disorder (MDD) who have not responded meaningfully to conventional treatments (eg, pharmacotherapy and psychotherapy). For these patients, possible therapeutic alternatives include neurosurgical treatments, such as deep brain stimulation (DBS) or ablative surgery. However, response rates in studies examining the efficacy of these treatments have been mixed. Several explanations have been proposed to account for the mixed findings, including patient selection, trial design, target selection and DBS parameters.1 One commonly overlooked reason might be that the primary outcome measures used in these trials (eg, measures of depressive symptom burden) do not fully capture improvements in all patients who in fact demonstrate improved quality of life and functioning.2
The Hamilton Depression Rating Scale (HAM-D) and the Montgomery–Åsberg Depression Rating Scale (MADRS) are the two most commonly used primary outcome measures in neurosurgical trials for MDD….