5: Sleep Disorders

When you can't sleep, you don't automatically think it's your brain's fault. Instead, you may blame that afternoon cappuccino. Many sleep disorders, however, have the brain to blame. One example is narcolepsy, a condition in which the brain can't maintain regular sleep cycles due to abnormalities in the neurons. As a result, a person with narcolepsy may not be able to sleep at night, and then during the day, he or she involuntarily falls asleep. To the outside observer, this may look like laziness or a late night.

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The brain might be behind a bad night's sleep.

While many college students trying to stay awake during an 8 a.m. class after a long night out may try to claim a case of narcolepsy, there's a little more to it than the desire to fall asleep at odd times. Narcolepsy is also distinguished by cataplexy, or sudden loss of muscle control, as well as vivid hallucinations and brief paralysis. However, the first symptoms to appear are those subtle signs that a person is tired, and as a result, many people don't understand that they're experiencing the onset of a neurological disorder.

Another sleep disorder linked to the brain is restless legs syndrome, a condition in which people lie down only to experience itching, tingling or some other odd sensation in the limbs that's only abated by movement. When your legs feel weird, you may not immediately wonder about what's going on in your brain. Indeed, some skeptics say this condition isn't rooted in the brain at all, but rather in the wallets of drug manufacturers eager to put you on prescription medication [sources: Woloshin, Schwartz; Hoffman]. Still, descriptions of the symptoms appear in 17th-century medical writings, and scientists currently believe the symptoms can be attributed to abnormal levels of dopamine and iron in the brain [source: Hoffman].

On the next page, we'll investigate a condition that's commonly confused with a normal part of the aging process.