Bt steps is a patient-centered behavioral therapy program that uses a manual and a computer-driven interactive voice response system to assess and treat obsessive compulsive disorder. This nine-step program contains a self-assessment module and a self-treatment module that provides teaching on exposure and ritual prevention. The patient reads about the steps in a manual and then uses a touch-tone telephone to contact the program, in which a recorded voice conducts the interview. Of 40 patients in an open 12-week trial in the United States and London, 35 completed the self-assessment module, and 17 completed at least two sessions of exposure and ritual prevention. The system produced statistically significant improvements on measures of obsessive compulsive disorder.