The aim of this study is to evaluate the efficacy of virtual reality exposure therapy (VRET) as a treatment for obsessive-compulsive disorder (OCD). Participants are randomly assigned to one of the following interventions: a) exposure condition - the group with a standard CBT program enriched with exposure therapy in VR (VRET), b) control condition 1 - the group with a standard CBT program enriched with VR cognitive training aimed at cognitive flexibility or c) control condition 2 - standard CBT program without any additional VR intervention. The treatment effect will be evaluated using pre/post assessments, as well as monitoring adherence to exposure and response prevention assignments.