Improving the outcome of complex obsessive-compulsive disorder

The primary objective of this thesis is to improve the treatment outcomes for persons with complex OCD. The thesis examines the heterogeneity of OCD, predictors of intensive treatment and OCD severity after two years, and factors related to insight and motivation for treatment. The heterogeneity of OCD is studied through two factor analyses of the Y-BOCS symptom checklist and an investigation into how persons with different OCD subtypes reacted to the COVID-19 pandemic. These factor analyses revealed that some factors are consistently identified across various studies and factor-analytical techniques, while others are less stable. Pre-pandemic contamination symptoms were linked to a heightened fear of COVID-19 and more severe contamination symptoms during the pandemic. In contrast, persons without pre-pandemic contamination symptoms reacted similarly to healthy controls. Two predictive studies identified several factors associated with an increased risk of requiring intensive treatment two years later and more severe OCD. Factors associated with a higher risk for intensive treatment include being single, having more severe comorbid depression, using psychotropic medication, and having a lower quality of life. Low physical activity was associated with higher OCD severity two years later compared to individuals with medium or high levels of physical activity. The studies on the course of insight and motivation revealed that insight varies during treatment. An improvement in insight was positively associated with a reduction in OCD severity. Lastly, a qualitative study found that videos of compulsions can potentially enhance both insight and motivation for treatment. The final conclusion of this thesis is that personalised care for OCD is of utmost importance. The specific nature of individual obsessions and compulsions, along with factors such as relationships, comorbid depression, quality of life, and physical activity, should all be considered. Based on this thesis, it is expected that addressing these aspects with evidence-based interventions could enhance the overall functioning of individuals with OCD.