one of two main types of group therapy defined by Russian-born U.S. psychotherapist Samuel Richard Slavson (1890–1981), the other being activity group therapy. Based on transference, interpretation, and other core principles of psychoanalytic theory—notably catharsis, insight, reality testing, and sublimation—analytic group psychotherapy was formally defined in 1950. It is divided into three subtypes: (a) play group psychotherapy for preschool children; (b) activity-interview group psychotherapy for schoolchildren 6 to 12 years old; and (c) interview group psychotherapy for adolescents and adults. Slavson believed group therapy to be fundamentally similar to individual treatment and a useful tool for producing personality changes without radically changing a person’s intrapsychic structure.