Effects of excessive daytime sleepiness and fatigue on overall health and cognitive function.

Excessive daytime sleepiness (EDS) can cause negative behavioral, physiologic, and cognitive effects, which limit patients' function and quality of life. Clinicians can screen for EDS using patient-report scales like the Epworth Sleepiness Scale or objective tests, such as the Multiple Sleep Latency Test. EDS and fatigue are common symptoms in many sleep disorders (eg, narcolepsy, obstructive sleep apnea), medical and neurologic conditions (eg, Parkinson's disease), and psychiatric disorders (eg, depression, substance abuse). Recognizing and managing comorbid conditions along with EDS can improve patients' quality of life.