The objective of this study is to evaluate psychiatric symptoms in Parkinson's disease (PD) patients and to assess their relation with other clinical aspects of PD. Psychotic symptoms (PS) and compulsive symptoms (CS) as well as other nonmotor and motor features were evaluated in 353 PD patients. Psychotic and compulsive symptom scores did not correlate significantly. PS occurred in 65% of patients, with item frequencies ranging from 10% (paranoid ideation) to 55% (altered dream phenomena). Regression analysis showed that autonomic impairment accounted for 20% of the 32% explained variance of PS, whereas cognitive problems, depression, daytime sleepiness, and dopamine agonist (DA) dose explained the rest. CS occurred in 19%, with item frequencies of 10% for both sexual preoccupation and compulsive shopping/gambling. Patients with more severe CS (score > or = 2 on one or both items) were significantly more often men, had a younger age at onset, a higher DA dose and experienced more motor fluctuations compared to the other patients. PS and CS are common but unrelated psychiatric symptoms in PD. The relations found between PS and cognitive problems, depression, daytime sleepiness, and autonomic impairment suggests a resemblance with Dementia with Lewy Bodies. The prominent association between PS and autonomic impairment may be explained by a shared underlying mechanism. Our results confirm previous reports on the profile of patients developing CS, and mechanisms underlying motor fluctuations may also play a role in the development of CS in PD.