1) To disseminate and examine the effectiveness of a manualized, individual, cognitive-behavioral psychotherapy (CBT) for adults with Generalized Anxiety Disorder(GAD), 2) to test the effectiveness of augmentation (the addition of) antidepressant therapy in participants who do not fully respond to CBT, and 3) to examine individual and clinical predictors of non-response to CBT and predictors of response to augmentation antidepressant therapy. A related goal is to examine the maintenance of treatment gains obtained from CBT alone and CBT with augmentation antidepressant therapy, over a twenty-four month follow-up period. This study will serve as a pilot investigation in preparation for a larger federally funded study using this treatment approach. We hypothesize that CBT will result in remission (no longer having GAD) and/or high endstate functioning (clinically meaningful improvement) in approximately 40-50% of participants. Further, we hypothesize that augmentation antidepressant therapy in participants who do not fully respond to CBT will result in further clinically significant improvement.