Cognitive behavioral therapy (CBT) is an empirically validated treatment for a wide variety of mental health difficulties including anxiety disorders, depression and bipolar disorders, obsessive-compulsive disorder, hoarding, insomnia, personality disorders, and psychotic disorders, to name a few. The validity of cognitive behavioral theory and the effectiveness of CBT have been well established by a steadily growing body of research that includes hundreds of studies conducted in recent decades. Indeed, CBT is recognized as a first-line treatment for both anxiety and depression (including subclinical presentations) in treatment guidelines from countries around the world.

Traditionally, CBT has consisted of one-on-one, individually administered treatment; however, the potential and practicality of CBT as a group intervention have been discussed since the earliest writings on the subject. In practice, a large ...