The proposed study is for a 6 week open-label clinical trial in which Seroquel XR is added to a selective serotonin reuptake inhibitor (SSRI) medication for the treatment of depressive and/or anxiety symptoms. Each subject will self-report changes in symptoms, functional impairment, etc. on a twice daily basis using a handheld computer (HHC) that transmits real-time symptoms reports to a central database. Each subject will be assessed in-person on a weekly or biweekly basis during the course of the study.

This study is a 6-week open-label clinical trial in which Seroquel XR is added to an antidepressant medication for the treatment of MDD with or without comorbid generalized anxiety disorder. Patients who are currently experiencing a depressive episode that has not responded to an adequate trial of an antidepressant will be eligible to participate. During the course of augmentation treatment with Seroquel XR, each subject will regularly enter information on symptom severity and functional impairment into their handheld computer, and this information will be wirelessly transmitted to a central database.

Inclusion Criteria:

1. Diagnosis of major depressive disorder, currently depressed with or without a comorbid generalized anxiety disorder as determined by DSM-IV diagnostic criteria (confirmed using the MINI)
2. Outpatient status
3. 17-item Hamilton Depression Rating Scale (HAM-D) score of ≥ 18
4. Treatment with any of the following antidepressant medications for the past 4 weeks at a minimum therapeutic dose

Exclusion Criteria:

1. Diagnosis of a past or current bipolar disorder
2. Current psychotic symptoms
3. Substance-induced mood disorder
4. Substance or alcohol dependence
5. Prominent current suicidal ideation as defined by a HAM-D item 3 (suicide item) score of ≥ 3
6. Current treatment with more than one antidepressant medication
7. Current treatment with an tricyclic (TCA) antidepressant or monoamine oxidase inhibitor (MAOI)
8. A patient with Diabetes Mellitus (DM)