**4. Course of the disorder**

While OCD has frequently been described as a debilitating and chronic illness whose symptoms wax and wane over time, less is known about the course of the disorder for children and adolescents specifically. In fact, research demonstrates potential differences regarding the course of illness between pediatric and adult populations. A study that compared pediatric and adult treatment-seeking individuals with OCD over a 3-year time period found that children had a significantly higher remission rate (53%) compared to adults (34%) [36]. Better psychosocial functioning as well as engaging in treatment earlier in the course of illness was related to shorter time to remission for children with OCD. These findings suggest a better prognosis for pediatric OCD and additionally emphasize the importance of early recognition and intervention for children with OCD [36].

Additionally, clinical presentation of OCD may vary across the life span between children, adolescents, and adults. Youth diagnosed with OCD at an earlier age tend to have higher rates of ADHD and anxiety disorders [1, 37]. As children with OCD age into adolescence, they are more likely to experience mood disorders such as depression [1, 16, 37]. These developmental trends are exemplified by a study that investigated differences in clinical presentation between 46 children, 55 adolescents, and 60 adults with OCD. Results revealed that ADHD and tic disorder rates were inversely related to age such that the children had the highest prevalence followed by adolescents and then adults [37]. Conversely, adults had the highest rates of depression followed by adolescents and then children with the lowest rates of depression [37]. Similarly, another study that examined the prevalence of comorbidity in pediatric OCD demonstrated adolescents had a six times greater likelihood of having a co-occurring depressive disorder compared to younger children [16].
