Psychotherapy can be regarded as a social influence situation in which the patient's relationship to the therapist is the primary vehicle for the production of therapeutic change. In individual psychotherapy, the situation is so arranged as to maximize the probability that the patient's interactions with the therapist will facilitate desirable changes in his attitudes, values, and action–tendencies. In group psychotherapy, the patient's relationships to his fellow–patients and to the group as a whole become additional vehicles for the production of therapeutic change. In choosing between group and individual therapy, one has to keep in mind, of course, that while group and individual therapy, one has to keep in mind, of course, that while the patient group–relationship may serve to strengthen forces toward change, it may also bring certain counterforces into play, thus reducing the potentiality for change contained in the dyadic relationship. Whether or not group therapy seems to be indicated, given these competing forces, will depend on the characteristics of the patient, the nature of his problems, and the current status of his general treatment program. Group therapy will be resorted to when there is a reason to believe that the combination of therapist and group wil lmake for more effective influence situation and facilitate the occurrence of the particular changes that are desired.