Process-outcome analysis in computer-aided treatment of obsessive-compulsive disorder

The study purpose was to examine dose-response relationships between behavior on a computer-delivered treatment program and outcome in obsessive-compulsive disorder (OCD), and to report the use of human-computer interactions (HCIs) as a process measure in psychotherapy research. Thirteen OCD patients completed three 45-minute sessions at weekly intervals on an interactive computer program which provided vicarious exposure and response prevention for OCD. The scenario modeled exposure to dirt for the treatment of a hand-washing ritual. HCIs were recorded and analyzed to provide a detailed description of the behavioral strategies used. The relationship between subject characteristics, process measures, and outcome was examined. Across the three computer treatment sessions, all subjects showed a marked increase in vicarious exposure behavior, that is, enacting a hand-dirtying behavior sequence on the interactive computer program. Some subjects enacted hand-washing, although this decreased across sessions. A higher amount of vicarious hand-dirtying behavior predicted symptom reduction on the Padua Inventory (PI). Higher National Adult Reading Test (NART) scores, an intelligence measure, predicted more enactments of hand-dirtying behavior, but the relationship between hand-dirtying and outcome remained significant after controlling for NART scores. We conclude that HCIs are a novel and objective process measure that may aid in clarifying specific treatment factors. The relationship between hand-dirtying and outcome suggests a likely increased benefit from higher treatment dosages.