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 6-year 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 (∼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.