This study will help clinicians increase their awareness of the existence of Bipolar II Disorder in the perinatal population and provide guidance in terms of appropriate treatment. Since this diagnosis in the postpartum population is done by elimination, this study will provide evidence of the merits of identifying and treating this order on time. When selective serotonin reuptake inhibitors (SSRIs) fail for symptom relief in women diagnosed with unipolar depression, postpartum onset, clinicians tend to either augment or combine a variety of psychotropic medications for treatment response. It is probably likely that these patients are Bipolar II Disorder who continue to cycle through the treatment. Adding an atypical antipsychotic is often an afterthought. Therefore, the unique aspects of treating this specific population right at the outset when a diagnosis of mood disorders is made is optimal. Clinicians not only need to actively consider bipolar type II in their differential diagnosis, but also to initiate treatment as soon as possible to relieve further suffering. This study will help diagnose postpartum Bipolar II Disorder and test the unique action of quetiapine with its mood stabilizing and antidepressant properties.