Possible causes of daytime sleepiness with particular regard to patients with Parkinson's disease

Excessive daytime sleepiness has many and diverse causes. Sleep disturbance is associated with dementia, depression, anxiety, ageing, and Parkinson's disease (PD); in fact, it affects an estimated 74%-89% of PD patients. While the drugs used to treat parkinsonism may improve some aspects of sleep disturbance, they may make other sleep problems worse. Also of concern is the fact that many of the medications used to treat depression, anxiety, and sleeplessness may cause daytime sleepiness. PD patients may need comedication for a variety of possible psychological, neurological, and physical conditions. The clinician must try to choose comedications from among the available medicines with a minimal propensity for causing daytime sleepiness, as well as offering patients clinical advice on how to manage episodes of daytime sleepiness.