This study evaluates the effects of an intensive therapy program designed for mentally handicapped persons with severely disturbed or autistic behavior on their staff personal which had an active role in the program. The staff members rated their professional competence, quality of interaction with the client, team culture and work satisfaction before and after being engaged in the program, with additional ratings of their personal aims at the beginning of the program. Three sets of data were obtained with the program being conducted three times in a row. The testings of the related as well as the independent samples show differentiated program effects. The main effect is an increase of the professional competence and quality of interaction, especially by the qualified staff members. Trainees put emphasis on the development of their personal relationship with the client. The results are discussed in terms of the impact of learning processes specific to the roles of the staff members and motivational factors on learning and therapy outcome, along with institutional conditions influencing successful learning. Thus the program facilitates the professional and interpersonal learning process of staff members in a specific way with success as well as with limitations.