In this thesis, longitudinal analyses have been performed on the PROPARK-Cohort, a hospital-based cohort of 421 patients followed for a period of five years. The main focus of this thesis was... Show moreIn this thesis, longitudinal analyses have been performed on the PROPARK-Cohort, a hospital-based cohort of 421 patients followed for a period of five years. The main focus of this thesis was to determine which predictors and associated factors contributed to the development of certain non-motor symptoms in Parkinson’s disease (PD). Strengths of our cohort study include the length of the follow-up period, broad clinical characterization, limited loss-to-follow-up and the large cohort size. The following non-motor symptoms have been addressed in this thesis: psychosis (hallucinations), dementia, excessive daytime sleepiness (EDS), insomnia, depression and anxiety. We found that while certain non-motor symptoms are inherent components of PD that increase in severity as the disease progresses, others symptoms such as excessive daytime sleepiness are inarguably caused by antiparkinsonian medication. For the future, we hope to see more longitudinal data on the disease progression in PD from large cohorts. Knowledge from longitudinal studies does not only contribute to more insight in the underlying pathobiology of PD, but it could also help the caregiver to monitor patients with particular risk factors more closely and adjust treatment if necessary. Show less