This paper presents a critical review of literature concerning research with diagnosed populations who participated in outdoor learning experiences as part of psychiatric therapy. The paper proposes: (1) to clarify the definition of the psychotherapy related to adventure programs; (2) to develop specific training manuals that can be shared and tested using quantitative and qualitative methods; (3) to address issues related to teaching traditionally-trained psychotherapist to become experientially-based outdoor leaders and professionals; (4) to make research accessible through development of a database of theoretical information; and (5) to share what outdoor therapists do with traditional therapists through traditional psychotherapy journals and at regional and national conferences. Through research and practice, adventure therapy will realize integrity, credibility, and reliability in the field of psychotherapy. This paper includes a list of research conducted with different diagnostic populations since 1980. (LP)