Ires Ghielen

42 Chapter 3 Abstract Introduction: Anxiety disorders occur in approximately one third of people with Parkinson’s disease (PD), and have a major impact on patient and caregiver wellbeing. In order to better understand and diagnose anxiety in PD patients, we investigated the generalizability of the results of a previous factor analysis on anxiety symptoms to a sample of PD patients with neuropsychiatric symptoms. Methods: Anxiety symptoms were measured with the Beck Anxiety Inventory (BAI) in 123 PD patients who were referred for neuropsychiatric diagnostics and treatment. Subscales of anxiety were analyzed through principal component analysis of BAI items. The associations between BAI subscales and motor and other neuropsychiatric symptoms were assessed through regression analyses. Results: Similar to the previous factor analysis, we found one psychological (affective) and four somatic subscales of anxiety in the BAI. The affective subscale was the principal component explaining 35.9% of the variance. The scores on the total BAI and the affective subscale were significantly associated with depressive symptoms. In a post-hoc analysis, the affective subscale had equal power as compared to the total BAI in predicting whether or not patients received an anxiety disorder diagnosis through psychiatric evaluation. Conclusion: Anxiety in PD is a complicated construct due to symptom overlap and mutual interactions. The affective subscale of the BAI shows potential as a screening tool for non-episodic anxiety in PD. We highly recommend evaluating anxiety symptoms in the context of other PD symptoms, including motor, autonomic, and other (neuro)psychiatric symptoms.