Excessive daytime sleepiness

# Overview
Excessive daytime sleepiness (EDS) is characterized by persistent sleepiness, and often a general lack of energy, even after adequate night time sleep. Sudden involuntary sleep onset, and microsleeps are common complications.  EDS is one of the two forms of hypersomnia, the other being prolonged nighttime sleep.
Persons with EDS are compelled to nap repeatedly during the day; fighting off increasingly strong urges to sleep during inappropriate times such as while driving, while at work, during a meal, or in conversations. As the compulsion to sleep intensifies, the ability to competently complete tasks sharply diminishes, which often mimics the appearance of intoxication.

# Diagnosis
An adult is considered to have excessive daytime sleepiness, if he or she is compelled to nap repeatedly during the day.
One diagnosis tool is the Epworth Sleepiness Scale, which helps determine the extent of EDS in a subject. A self test is available from Stanford University Medical School.

# Causes
EDS can be caused by a variety of factors:
- Insufficient quality and quantity of night time sleep.
- Misalignments of the body's circadian pacemaker with the environment (eg. jet lag, shift work or other circadian rhythm sleep disorders).
- The symptom of an underlying sleep disorder, such as narcolepsy, sleep apnea, hypersomnia, or restless legs syndrome.
- Disorders such as clinical depression.
- Tumors, head trauma, anemia, kidney failure, hypothyroidism, or an injury to the central nervous system.
- Smoking, and drug or alcohol abuse.
- Genetic predisposition.

# Coping
Some people lose the ability to adequately function in family, social, occupational, or other settings. A proper diagnosis, and treatment, of the underlying cause can help mitigate such complications.
It is often extremely difficult to accept that EDS is beyond a person's control. The unaffected see sleepiness as an insult, a rejection, or as evidence for lack of interest. Family members equate pathological sleepiness with their normal experiences of sleepiness, and mistakenly assume that, if the person really wanted to, they could "fight it off". As a result, family members with even a rudimentary understanding of the disorder, often conclude they're "just not trying hard enough". What must be clearly understood, is that EDS is often totally beyond a person's volition.
To further confuse things, during occasional unique and/or stimulating circumstances, a person with EDS can sometimes remain animated, awake and alert, for brief or extended periods of time. Such circumstances can include unusual guests, experiences, or situations. This lends credence to an observer's assertions that, the alertness is simply a matter of self control, and that EDS can be 'willed away'. With EDS, the normal correlation between interest and wakefulness simply does not hold. Asserting someone can 'fight off' EDS, is as illogical as concluding no one needs sleep simply because nearly all people can fight off sleep during unique or emergency situations.
EDS needs to be defended as the manifestation of a disorder, and not signs of a willful lack of effort. Without firm and knowledgeable counseling on the part of the physician, family members can easily fail to accept EDS as part of an illness.
People with EDS also may sleep for a full night of sleep and still wake up feeling exausted, no matter what the circumstance. Staying up for a full night and sleeping a couple of hours could have them feeling refreshed as well, their sleeping patterns are totally random.
One with EDS can also engage in activity one finds enjoyable and not feel any onset of sleep until said activity ends.