Generalized anxiety disorder (GAD) is a chronic condition characterized by worry and concomitant anxiety symptoms that cause extreme distress and/or interfere with function. The 12-month prevalence of GAD in the general population ranges in studies from approximately 2% to 5%, with the majority of cases occurring comorbid with major depression. GAD is particularly prevalent in certain special populations, such as older adults, in whom it is the most common anxiety disorder. In clinical and community studies, GAD emerges as a strong predictor of functional impairment, over and above that explained by major depression. These observations lead to the conclusion that current public health efforts focused on identification and treatment of major depression should be extended to include GAD and other anxiety disorders.