The prevalence and determinants of neuropsychiatric symptoms in late‐stage parkinsonism

Background Late-stage parkinsonism and Parkinson's disease (PD) are insufficiently studied population. Although neuropsychiatric symptoms (eg, psychosis, depression, anxiety, behavioral problems) are frequently present, their prevalence and clinical predictors remain unknown. Objective To determine the prevalence and predictors of neuropsychiatric symptoms in late-stage PD. Methods We conducted a multinational study of patients with PD with ≥7 years disease duration and either a Hoehn and Yahr stage ≥4 or a Schwab and England score ≤ 50% in the on stage. Neuropsychiatric symptoms were assessed through interviews with carers using the Neuropsychiatric Inventory, with a frequency × severity score ≥ 4, indicating clinically relevant symptoms. The determinants analyzed were demographic characteristics, medication, and motor and nonmotor symptoms. Univariate and multivariate logistic analyses were performed on predictors of clinically relevant neuropsychiatric symptoms. Results A total of 625 patients were recruited in whom the Neuropsychiatric Inventory could be completed. In 92.2% (576/625) of the patients, at least 1 neuropsychiatric symptom was present, and 75.5% (472/625) had ≥1 clinically relevant symptom. The most common clinically relevant symptoms were apathy (n = 242; 38.9%), depression (n = 213; 34.5%), and anxiety (n = 148; 23.8%). The multivariate analysis revealed unique sets of predictors for each symptom, particularly the presence of other neuropsychiatric features, cognitive impairment, daytime sleepiness. Conclusion Neuropsychiatric symptoms are common in late-stage PD. The strongest predictors are the presence of other neuropsychiatric symptoms. Clinicians involved in the care for patients with late-stage PD should be aware of these symptoms in this specific disease group and proactively explore other psychiatric comorbidities once a neuropsychiatric symptom is recognized.