The technique of formally organized group therapy is said to have been devised by J. H. Pratt in 1905. Pratt was holding general-care instruction classes for recently discharged tuberculosis patients when he noticed the impact of this experience on their emotional states. In 1925 psychoanalyst Trigant Burrow became dissatisfied with individual psychoanalysis, and began experimenting with group techniques. Burrow hoped to decrease the authoritarian position of the therapist, and to more thoroughly examine interpersonal interactions. The application of group therapy methods to prison inmates and discharged mental hospital patients was pioneered by Paul Schilder and Louis Wender in the 1930s. At that time group therapy was found to be particularly useful in the treatment of children and adolescents. The development of group therapy was given impetus during World War II, as a result of the large number of soldiers requiring treatment.
There are various types of group therapy; approaches include behavior therapy, psychoanalytic therapy, sensitivity training, or Gestalt psychology (see psychotherapy). The composition of groups varies as well, with family therapy and marriage counseling common forms in recent years. Peer group therapy usually consists of a group of individuals who have similar problems, and can be mediated by a psychoanalyst or by the members themselves. Many people seeking help prefer this sort of group therapy over individual therapy, largely because of the comfort derived from knowing that others share their problems. The approach is nondirective, and in some cases, the individual can continue attending sessions whenever they are needed. Alcoholics Anonymous (AA) is a well-known peer support group, run entirely by members. AA has been influential in the formation of similar groups, particularly support groups centered on addictions.
See S. Hearon, Group Therapy (1984); S. Bloch and E. Crouch, Therapeutic Factors in Group Psychotherapy (1987).
In the United Kingdom group psychotherapy initially developed independently, with pioneers S. H. Foulkes and Wilfred Bion using group therapy as an approach to treating combat fatigue in the Second World War. Foulkes and Bion were psychoanalysts and incorporated psychoanalysis into group therapy by recognising that transference can arise not only between group members and the therapist but also among group members. Furthermore the psychoanalytic concept of the unconscious was extended with a recognition of a group unconscious, in which the unconscious processes of group members could be acted out in the form of irrational processes in group sessions. Foulkes developed the model known as Group Analysis and the Institute of Group Analysis, while Bion was influential in the development of group therapy at the Tavistock Clinic. Bion has been criticised, for example by Yalom, for his technical approach which had an exclusive focus on analysis of whole-group processes to the exclusion of any exploration of individual group members' issues. Despite this, his recognition of group defences in the "Basic Assumption Group", has been highly influential.
Bion's approach is comparable to Social Therapy, first developed in the United States in the late 1970s by Lois Holzman and Fred Newman, which is a group therapy in which practitioners relate to the group, not its individuals, as the fundamental unit of development. The task of the group is to "build the group" rather than focus on problem solving or "fixing" individuals.
Group therapy can form part of the therapeutic milieu of a psychiatric in-patient unit or ambulatory psychiatric Partial hospitalization (also known as Day Hospital treatment). In addition to classical "talking" therapy, group therapy in an institutional setting can also include group-based expressive therapies such as drama therapy, psychodrama, art therapy, and non-verbal types of therapy such as music therapy. Group psychotherapy is a key component of Milieu Therapy in a Therapeutic Community. The total environment or milieu is regarded as the medium of therapy, all interactions and activities regarded as potentially therapeutic and are subject to exploration and interpretation, and are explored in daily or weekly community meetings
A form of group therapy has been reported to be effective in psychotic adolescents and recovering addicts. Projective group therapy uses an outside text such as a novel or motion picture to provide a "stable delusion" for the former cohort and a safe focus for repressed and suppressed emotions or thoughts in the latter. Patient groups read a novel or collectively view a film. They then participate collectively in the discussion of plot, character motivation and author motivation. In the case of films, sound track,cinematography and background are also discussed and processed. Under the guidance of the therapist, defense mechanisms are bypassed by the use of signifiers and semiotic processes. The focus remains on the text rather than on personal issues.
There is clear evidence for the effectiveness of group psychotherapy for depression: a meta-analysis of 48 studies showed an overall effect size of 1.03, which is clinically highly significant. Similarly, a meta-analysis of five studies of group psychotherapy for adult sexual abuse survivors showed moderate to strong effect sizes , and there is also good evidence for effectiveness with chronic traumatic stress in war veterans. There is less robust evidence of good outcomes for patients with borderline personality disorder, with some studies showing only small to moderate effect sizes. The authors comment that these poor outcomes might reflect a need for additional support for some patients, in addition to the group therapy. This is borne out by the impressive results obtained using Mentalization based treatment, a model which combines dynamic group psychotherapy with individual psychotherapy and case management. Most outcome research is carried out using time-limited therapy with diagnostically homogenous groups, however long-term intensive interactional group psychotherapy assumes diverse and diagnostically heterogeneous group membership, and an open-ended time scale for therapy. Good outcomes have also been demonstrated for this form of group therapy.