Pathophysiology and pharmacological management for sleep problems in Parkinson's disease

Sleep problems are among the most frequently reported non-motor symptoms of Parkinson's disease (PD), with a broad range of disorders: insomnia, REM sleep behavior disorder, restless legs syndrome, excessive daytime sleepiness, and sleep-related breathing disorders. These disturbances evolve in complexity across PD severity stages, significantly impact the patients' quality of life and may exacerbate motor and other non-motor symptoms. Neurodegenerative processes, impaired function of neurotransmitters, medication side effects, circadian rhythm dysfunction are among the most proposed mechanisms that may explain the frequent occurrence of sleep disorders in PD. However, there are still many unanswered questions related to the pathophysiological mechanisms of sleep disorders in PD that may offer the clue to better therapeutical options. Although the prevalence of sleep disturbances is very high, the treatment options are still limited. The current review focuses on main sleep disturbances encountered in PD, pathophysiological insights, current therapeutical options and future perspectives for a better and more personalized management of these disorders in PD.