Quetiapine Extended Release (XR) in Bipolar Patients With Comorbid Generalized Anxiety Disorder (GAD)

120 subjects aged 18 and up with Diagnostic and Statistical Manual -IV Generalized Anxiety Disorder and Bipolar Disorder type I or II as identified by extensive clinical interview and the Mini-International Neuropsychiatric Interview (MINI) will be enrolled and randomized. Assignment to each arm will be balanced for BP I vs BP II; male vs female; and with vs without SUD. Potential participants will be recruited by means of Institutional Review Board -approved advertising or from the clinical psychiatric infrastructure. This study is a randomized, double-blind, placebo-controlled, 8-week comparison of quetiapine sustained-release monotherapy or adjunctive mood stabilizer therapy vs. placebo in the acute treatment of comorbid generalized anxiety disorder in patients with bipolar disorder with or without a substance use disorder. Subjects will be assessed weekly for mood changes and side effects.