Time vortex: the circadian–dopaminergic dialogue in Parkinson’s disease

Circadian disruption is a prominent non-motor feature of Parkinson's disease (PD) and is bidirectionally linked to PD pathology. It may interact with oxidative stress, inflammation, mitochondrial dysfunction, and proteostasis imbalance, though its causal role remains unclear. Circadian parameters may aid early diagnosis, monitoring, and time-oriented interventions. This review discusses how circadian abnormalities relate to prodromal and clinical PD, related mechanisms, and circadian-based therapies to improve quality of life.