Clinical and sociodemographic predictors of response to augmentation, or dose increase among depressed outpatients resistant to fluoxetine 20 mg/day

Objective: Patients with major depressive disorder often show only partial or no response to antidepressants, necessitating next-step interventions such as dose increase or augmentation. Factors moderating response to these next-step interventions are not well-studied. Method: In this randomized, double-blind investigation of next-step treatments in 101 outpatients who failed to respond to fluoxetine 20 mg for 8 weeks, the impact of depressive course and sociodemographic factors on likelihood of treatment response following dose increase or lithium or desipramine augmentation was examined. Results: After controlling for depression severity at baseline, current marriage and earlier onset of depression were associated with greater likelihood of response in a logistic regression. Intervention strategy was not predictive of response. Conclusion: Marital status and earlier onset of depression may be clinically useful in predicting outcome following any next-step intervention for treatment resistance, rather than with particular strategies.