Abstract
Apathy is a disabling symptom in Parkinson's disease (PD). The effect of dopaminergic treatment on apathy is inconsistent, depending on the stage of the disease, the type of apathy and strongly influenced by placebo effect. Our study assessed the evolution of a cohort of 86 de novo, drug naive PD patients for 4 years, after dopaminergic treatment introduction. The main objective of the study was the change of apathy from baseline to follow-up and secondary outcomes were the change of other neuropsychiatric symptoms. At 4 years there was an improvement of apathy (p = 0.002), mainly driven by improvement of baseline apathy (p = 0.001). This was associated with an improvement of anxiety (p = 0.001), an increase in hyperdopaminergic behavior including nocturnal hyperactivity with consecutive diurnal sleepiness (p = 0.001 and p < 0.001), independently of the presence of apathy at baseline. These findings confirm, in a large real-life cohort, that dopaminergic treatment improves motivational apathy in early PD.