A Study of Quetiapine Fumarate Sustained Release in Major Depression With Comorbid Fibromyalgia Syndrome

To compare the efficacy of Quetiapine SR versus placebo over 8 weeks in unipolar non-psychotic adult outpatients depression and comorbid fibromyalgia. This will be measured by the last observation carried forward (LOCF) mean change from baseline to week 8 on the Hamilton Depression Scale (HAM-D) total score. For the purposes of this study, response regarding improvement in depressive symptoms will be defined as a 50% decrease in HAM-D scores over 8 weeks. Furthermore, proportion of patients achieving remission is defined as an HAM-D total score of 7 at end of treatment. The anxiety comorbid symptoms often associated with major depression will be assessed with the HAM-A (14 items) scale. Proportion of patients responding and achieving remission of anxiety symptoms are defined respectively as a reduction of 50% in the HAM-A total score from baseline and a HAM-A total score of 7 at the end of treatment.