ABSTRACT

Excessive sleepiness is pervasive in our society affecting up to 13% of the population (1). Sleepiness is experienced as a subjective difficulty maintaining alertness accompanied by a rapid entrance into sleep when the person is sedentary. Often this leads to decrements in quality-of-life, cognitive impairment, and increased accidents (2,3). Each year in the United States greater than 50,000motor vehicle accidents are attributed to driving while drowsy (4). Sleepiness has many causes including insufficient sleep, sleep disorders, medical and neurological illness, and medication side effects. This chapter focuses on sleep disorders where excessive sleepiness is the primary symptom; this includes narcolepsy (sporadic and secondary), idiopathic hypersomnia, hypersomnia due to medical conditions (posttraumatic hypersomnia), recurrent hypersomnia, and behaviorally induced insufficient sleep syndrome.