Clinical and demographic predictors of improvement during duloxetine treatment in patients with major depression: an open-label study.

BACKGROUND AND OBJECTIVES

Currently evidence about clinical and demographic predictors of response to newer antidepressants such as duloxetine is limited. This study aimed to investigate whether a number of predictors, particularly co-morbid anxiety disorders and anxious depression, are associated with clinical improvement.

METHODS

One hundred and one outpatients suffering from major depression (MD) were treated with duloxetine and assessed at baseline and at weeks 2, 4 and 8 on the 21-item Hamilton Depression Rating Scale (HDRS) and at weeks 4 and 8 on the Clinical Global Impression-Severity (CGI-S) scale.

RESULTS

Patients with co-morbid panic disorder or obsessive-compulsive disorder showed slowed improvements at 2 and 4 weeks compared with patients without such co-morbidities; however, they showed slightly higher or similar improvements, respectively, at 8 weeks. Also, anxious MD patients showed higher improvements compared with non-anxious MD patients at all time points, with the difference between groups increasing over time. Several other predictors, such as co-morbid premenstrual dysphoric disorder and lifetime generalized anxiety disorder, were also identified.

CONCLUSION

Our results suggest that co-morbidity with an anxiety disorder could negatively influence improvement following duloxetine treatment in the short term but that such a difference could be reversed by 8 weeks. However, given that the study had several limitations, including the lack of a comparison group and a flexible dosage design, further research is needed to replicate and extend these findings.