Time course of improvement of different symptom clusters in patients with major depression and pain treated with duloxetine or placebo

Objective: This post hoc analysis assessed improvements in a broad range of psychopathological dimensions and in interference of pain with functioning as well as the time course of these improvements in patients with major depressive disorder (MDD) and pain treated with duloxetine versus placebo. Research design and methods: Data were derived from an 8-week, double-blind, placebo-controlled study in adult outpatients with MDD and non-specific physical pain. Mean times between improvement in Brief Pain Inventory (BPI) pain severity and interference of pain with functioning, depression severity, and dimensions of the Symptom Checklist-90 Revised (SCL-90-R) subscales were evaluated by responder analysis. Results: For all SCL-90-R subscores, a higher percentage of duloxetine-treated patients reached responder status (50% improvement) as compared to placebo, of these anger/hostility and interpersonal sensitivity had the highest response rates. In the duloxetine-treated group, response for anger/hostility, phobic anxiety, psychoticism, and most items assessing interference of pain with functioning was reached earlier than response for pain severity. The times to response for Montgomery-Asberg Depression Rating Scale (MADRS) and for pain severity were similar. In the placebo-treated group, times to response for depression, anxiety, and MADRS were longer than response for pain severity. Conclusions: Duloxetine, and to a lesser degree placebo, not only improved depressive symptomatology and pain severity but also a much broader range of psychopathological symptoms. Time courses of improvements were different for duloxetine and placebo, in that depression and interference of pain with functioning improved earlier than pain severity in duloxetine-treated patients but not in placebo-treated patients. These results suggest that time to response is a valuable means of characterizing treatment effects. Limitations: Pain was only assessed as a symptom and no further clinical diagnosis for pain syndromes were performed.