OBJECTIVE: Cognitive behavioral therapy (CBT) is regarded as one of the most effective intervention for obsessive-compulsive disorder (OCD). However, many patients remain untreated or inadequately treated due to time or geographical constraints. The purpose of this study was to develop an internet-based CBT (ICBT) for OCD, and to examine its efficacy in the Korean clinical setting. 

METHODS: The ICBT program ('COT') was developed from the same OCD manual in the standard CBT intervention. Twenty-seven participants of the total 42 patients completed all training sessions of the ICBT and the remainder (n=15) were classified as non-completers. Self-report measures of OCD, depression, anxiety, and work/social functioning, in addition to a neurocognitive test battery, were administered by face-to-face before and after treatment. 

RESULTS: The participants showed significant improvements in OCD and depressive symptoms, and in work/social functioning after ICBT completion. The presence of combined medication had no significant impact on treatment effect. The non-completers displayed more severe depressive and anxiety symptoms, and ICBT responders were younger and performed better in the Wisconsin Card Sorting Test. 

CONCLUSION: ICBT was found to be as effective for patients with moderate OC symptoms and little treatment experience. Considering the high accessibility and convenience of ICBT, it could be a helpful first treatment step for OCD patients when face-to-face treatment is unavailable. In the future a randomized controlled study will be necessary for verification and generalization of these results.