A Pooled MADRS/IDS Cross-Correlation Analysis

Abstract

These analyses aimed to examine the pattern of improvement in depression symptoms with adjunctive aripiprazole. Data were pooled (724 subjects: n = 356 placebo, n = 368 aripiprazole) from 2 double-blind, 6-week aripiprazole studies. Pearson correlation coefficients (r) were calculated between changes on the Montgomery-Asberg Depression Rating Scale (MADRS) line items and selected Inventory of Depressive Symptomatology (IDS) line items using last observation carried forward. The magnitude of change was expressed as a between-group effect size (ES). At end point, adjunctive aripiprazole demonstrated significant improvement versus antidepressant therapy alone in 8 of the 10 MADRS items (MADRS total score Cohen effect size = 0.37) and 12 of the 30 IDS items (IDS total score Cohen ES = 0.18). Analysis of correlation data identified 5 MADRS items assessing mood, lassitude, inability to feel, self-worth, and suicidal thoughts that correlated with similar IDS items; these showed a similar pattern of rapid, sustained response to adjunctive aripiprazole and a similar ES. Other symptoms associated with depression (tension associated with feeling anxious, irritability, and lack of concentration) did not show statistically significant changes on either scale at end point. The IDS identified an additional 3 important depression-related symptoms (diminished libido, view of self, and interpersonal sensitivity) that showed significant rapid and sustained improvement with adjunctive aripiprazole. This cross-correlation analysis confirmed that improvement in core depressive symptoms with adjunctive aripiprazole was identified by both clinicians and patients. Clinically, these changes were maintained during the study. Theoretically, these findings lead to important questions regarding neurochemical changes produced by aripiprazole when used in combination with antidepressants.