Group therapy has become the most widely used psychosocial treatment for substance abuse and addiction, and for most patients it remains the treatment of choice. Group therapy has been found to be clinically effective and cost-effective for both the prevention and treatment of substance abuse. The use of group therapy can address some of the relevant psychosocial issues leading to substance abuse, many of the symptoms and difficulties resulting from substance abuse and dependence, and the treatment of co-occurring psychiatric disorders. The etiology of substance abuse is most likely multifactorial, including genetic, developmental, familial, physiological, intrapsychic, interpersonal, sociocultural, and environmental factors and interpersonal attachment issues. Therefore, the treatment of substance abuse and dependence must also be multidisciplinary, using a biopsychosocial framework and including the use of medications; outpatient, inpatient, and residential treatment; and psychosocial interventions. Substance abuse may be regarded as a familial disorder, so that the parent–child mutual attachment relationship, peer interactions, personality and behavioral issues, and cultural factors such as ethnic identification (J. S. Brook et al. 2006), are important areas to explore in group therapy. Such a broad multidisciplinary approach has allowed group therapists to address diverse areas in the treatment of patients (Vannicelli 1992, 1995).