17. My friend sleeps a lot ((sometimes up to 14 hours a day if she can manage)), and I was wondering if she might have some sort of underlying disability that would cause this? Are there any kind of sicknesses or disabilities with excessive somnolence as a symptom?

ANSWER:

Your friend should see their doctor for a diagnosis. Teenagers need about 9 hours of sleep per day. Adults need 8 to 7 hours. Sleep problems can affect you negatively in many ways and even be dangerous. It affects your ability to think, your coordination, and can even be just as dangerous when your driving as drinking is.

Our brain controls whether we sleep or are awake by using different kinds of chemicals (neurotransmitters). The neurotransmitters act on the cells in the brain (neurons). To learn more about the brain go to:

http://www.theablecrew.org/interactive/brainworks.htm

Serotonin is a neurotransmitter that controls your mood, emotion, sleep and appetite.

Norepinephrine causes blood vessels to constrict, increases heart rate, blood pressure, and the sugar level of the blood.

These two chemicals keep some parts of the brain active while other parts are asleep.

Research also suggests that another chemical called adenosine builds up in our blood while we are awake and causes drowsiness. This chemical gradually breaks down while we sleep.

MedlinePlus Sleep Disorder Tutorial

Some people, no matter how much sleep they get during the night, still feel sleepy during the day. There are many possible causes for excessive sleepiness including:

sleep disorders

•  shift work sleep disorder

•  Circadian rhythm which is when the body sleeps at night and is awake during the day is disrupted

•  Difficult to function at work, at home and socially

•  sleep apnea

•  The brain forgets to tell the body to take a breath

•  Wake up occurs from lack of oxygen

•  The tongue and the back of the throat will sometimes stop breathing during sleep

•  insomnia

•  Difficulty going to sleep or staying asleep

•  Waking up many times per night

•  Waking up and unable to go back to sleep

neurological disorders

•  narcolepsy

•  Uncontrolled sleep, even when you have slept all night

•  Attacks of muscle weakness in the face, neck, throat, arms, legs or back

•  Uncontrolled dream-like state

•  restless legs syndrome

•  Neurological disorder

•  Strong irresistible urge to move legs

•  Pain and uncomfortable sensations in legs feet and sometimes arms

•  May have involuntary movement of legs and arms

•  Multiple Sclerosis

•  Parkinson's Disease

Psychiatric disorders

• depression
  
• anxiety

http://www.ninds.nih.gov/disorders/brain_basics/understanding_sleep.htm |  http://www.excessivesleepiness.com/