Generalized anxiety disorder (GAD) is characterized by anxiety, excessive and uncontrollable worry, and somatic symptoms such as muscle tension and difficulty concentrating (DSM-IV-TR, American Psychiatric Association, 2000). GAD is linked to symptoms of depression both theoretically and empirically, but there is currently no consensus as to how co-occurring depressive symptoms affect GAD treatment outcome. Dugas and colleagues have developed an efficacious cognitive-behavioural treatment (CBT) based on a model of GAD that centres upon intolerance of uncertainty. This CBT program has demonstrated consistent reductions in GAD symptom severity by posttreatment (e.g., Dugas et al., 2010); however, not all individuals achieve full remission of GAD for reasons that are currently unclear. The first goal of this study was to determine the relationship between depressive symptoms and short- and long-term GAD treatment outcome. The second goal was to determine the relationship between depressive symptoms and GAD treatment engagement. The results indicated that depressive symptoms at pretreatment were largely unrelated to posttreatment severity of GAD, worry, and somatic anxiety or to treatment engagement. Posttreatment depressive symptoms were not related to the severity of overall GAD symptoms, worry, and somatic anxiety at 18-month follow-up. The theoretical and clinical implications of these findings are discussed
