The possible influence of cognitive dissonance in psychotherapy was examined by conceptualizing therapy as an effort justification process. It was predicted that freely choosing to undergo a highly effortful procedure would aid in positive therapeutic change. Subjects (N=52) participated in a weight-reduction experiment in which the degree of effort expended on "therapeutic" tasks and the degree of perceived choice to discontinue the study were manipulated. High-Effort subjects lost marginally more weight. Evidence was also found for the influence of the choice variable. A follow-up revealed that the effects of effort had increased and were highly significant. (Author)