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.