Long-term remission rates and trajectory predictors in obsessive-compulsive disorder: Findings from a six-year naturalistic longitudinal cohort study

Background: This naturalistic study, utilizing data from the Netherlands Obsessive-Compulsive Disorder Association (NOCDA) cohort, investigated the long-term remission rates and predictors of different trajectories of obsessive-compulsive disorder (OCD) within a clinical population. Methods: A sample of 213 participants was classified into three illness trajectories: '' Chronic,'' '' Episodic, '' and '' Remitted-OCD.'' Long-term remission rates were calculated based on three follow-up measurements over a 6year period. A multinomial logistic regression model, incorporating five selected predictors with high explanatory power and one covariate, was employed to analyze OCD trajectory outcomes. Results: The long-term full remission rates, calculated from all the measurements combined (14%), were significantly lower than what was observed in earlier studies and when compared to assessments at each individual follow-up (similar to 30%). Moreover, high baseline symptom severity and early age of onset were identified as significant risk factors for a chronic course of OCD, while male sex and younger age predicted a more favorable trajectory. Notably, the likelihood of an episodic course remained high even without identified risk factors. Limitations: The bi-annual data collection process is unable to capture participants ' clinical conditions between assessments. Additionally, no data was collected regarding the specific type and duration of psychological treatment received. Regarding the type of treatment participants received. Conclusions: Results suggest that long-term remission rates may be lower than previously reported. Consequently, employing multiple assessment points in longitudinal studies is necessary for valid estimation of long-term full remission rates. The results emphasize the importance of personalized clinical care and ongoing monitoring and maintenance for most OCD cases.