Sleep and Disease
and sleep-related problems play a role in a large number of
human disorders and affect almost every field of medicine.
For example, problems like stroke and asthma attacks tend to
occur more frequently during the night and early morning,
perhaps due to changes in hormones, heart rate, and other
characteristics associated with sleep.
Sleep also affects some kinds of epilepsy in complex ways.
REM sleep seems to help prevent seizures that begin in one
part of the brain from spreading to other brain regions,
while deep sleep may promote the spread of these seizures.
Sleep deprivation also triggers seizures in people with some
types of epilepsy.
Neurons that control sleep interact closely with the immune
system. As anyone who has had the flu knows, infectious
diseases tend to make us feel sleepy. This probably happens
because cytokines, chemicals our immune systems
produce while fighting an infection, are powerful
sleep-inducing chemicals. Sleep may help the body conserve
energy and other resources that the immune system needs to
mount an attack.
Sleeping problems occur in almost all people with mental
disorders, including those with depression and
schizophrenia. People with depression, for example, often
awaken in the early hours of the morning and find themselves
unable to get back to sleep. The amount of sleep a person
gets also strongly influences the symptoms of mental
disorders. Sleep deprivation is an effective therapy for
people with certain types of depression, while it can
actually cause depression in other people.
Extreme sleep deprivation can lead to a seemingly psychotic
state of paranoia and hallucinations in otherwise healthy
people, and disrupted sleep can trigger episodes of mania
(agitation and hyperactivity) in people with manic
Sleeping problems are common in many other disorders as
well, including Alzheimer's disease, stroke, cancer, and
head injury. These sleeping problems may arise from changes
in the brain regions and neurotransmitters that control
sleep, or from the drugs used to control symptoms of other
disorders. In patients who are hospitalized or who receive
round-the-clock care, treatment schedules or hospital
routines also may disrupt sleep.
The old joke about a patient being awakened by a nurse so he
could take a sleeping pill contains a grain of truth. Once
sleeping problems develop, they can add to a person's
impairment and cause confusion, frustration, or depression.
Patients who are unable to sleep also notice pain more and
may increase their requests for pain medication. Better
management of sleeping problems in people who have other
disorders could improve these patients' health and quality
What Happens When You Sleep?
The Different Stages of Sleep
Source: National Institute of Neurological Disorders and