Most physical illnesses can lead to sleep disorders, usually due to associated symptoms such as pain, frequent urination, coughing, breathing difficulties, belching or itching. Other medical conditions, such as Parkinson’s or Alzheimer’s disease, can disrupt sleep by directly affecting the brain.
Sleep apnea
In sleep apnea, periods of exceptionally loud snoring and heaving alternate with a silence of up to half a minute (and sometimes much longer) in which breathing comes to a standstill. You probably don’t know about your startling sleeping habits unless you are told about it by your bedmate who is terrified. You wake up unrested and you doze off during the day. Sleep apnea can have a number of different causes, but is most commonly found in people who are overweight.
Narcolepsy
Narcolepsy is an inherited neurological disorder in which the regulation of REM sleep is disrupted. You suffer from uncontrollable sleep attacks that can occur in inappropriate circumstances and can even be dangerous while you are driving, attending a lecture or even in the middle of a conversation.
The sleep period usually lasts about fifteen minutes, after which you wake up completely rested and refreshed, but the extreme drowsiness can return within a few hours and lead to the next attack. Many of the symptoms in narcolepsy represent elements of REM sleep invading daytime life.
Cataplexy
Cataplexy is a sudden loss of muscle tone that can be so complete that you collapse. This can be seen as a daytime attack of sleep paralysis (a normal part of REM sleep). Cataplexy is usually preceded by an intense emotion, such as great anger, despair, shock or laughter.
Sometimes elements of REM sleep take over when you’re in the process of falling asleep or waking up. You may be awake and still have dream-like hallucinations and discover that you cannot speak or move a single muscle in your body. Although this is very frightening, it usually goes away after a few minutes. Perhaps this is the origin of some zombie stories.
Diagnostics according to DSM IV
According to the diagnostic manual, you have a sleep disorder due to a medical condition if the following occurs:
- You have trouble falling asleep or staying asleep, you sleep too much or feel sleepy during the day.
- Your sleep problem is a direct result of a medical condition or the discomfort it causes.
- Your sleep problem is serious enough to hinder your daily functioning.
