The impaired ability to suppress an inappropriate but pre-potent response (response inhibition; RI) characterizes several debilitating clinical problems, including obsessive-compulsive and related disorders (OCRD) such as obsessive-compulsive disorder, trichotillomania, and skin picking disorder. There is a critical need to develop an effective and durable treatment for OCRDs with demonstrable evidence for improving impaired RI. The purpose of our project is to examine the impact of a novel computerized intervention, response inhibition training (RIT), on neural indices of RI, and examine the mechanistic link between engagement of the neural RI targets and change in OCRD symptoms. To this end, this project will conduct a randomized clinical trial for individuals with OCD, trichotillomania, and/or skin picking disorders. Participants will be randomly assigned to 8 to 16 sessions of computerized RIT or a computerized placebo training. Various clinical, behavioral, and brain-imaging data will be acquired to evaluate the training effects at baseline, post-training, and 1-month follow-up periods.