Bridging Technology and Psychotherapy: Mixed Reality Exposure and Response Prevention for Contamination-Related Obsessive-Compulsive Disorder.

Mixed reality exposure and response prevention (MERP) has been proposed as an innovative format to address barriers that limit the implementation of traditional in vivo exposure and response prevention (ERP) in obsessive-compulsive disorder (OCD). This case report illustrates the clinical application of MERP in a 57-year-old woman with chronic contamination-related OCD who had previously completed extensive outpatient psychotherapy, including cognitive behavioral therapy with ERP, with only temporary improvement. As part of a randomized controlled trial, she received six therapist-led MERP sessions in which disorder-relevant virtual contamination cues were superimposed onto the real therapy environment to enable immersive exposure while maintaining ecological validity. MERP was well accepted, and no adverse events occurred. Symptom severity decreased from severe to moderate on the Yale-Brown Obsessive-Compulsive Scale (26-20), with marked improvement in obsessions, reduced avoidance, and increased ability to refrain from neutralization. The patient reported a greater sense of agency and successful transfer of exposure principles into daily life. The case highlights typical challenges observed in MERP, including fluctuations in sense of immersion, technical limitations that affect stimulus stability, and covert mental neutralization, and outlines practical strategies to address them. Overall, the report demonstrates that MERP is a feasible and acceptable delivery format for ERP in contamination-related OCD and provides clinically relevant insights for optimizing its implementation in routine care.