Narcolepsy is a sleep disorder where the patient suffers from sudden episodes of forced sleep lasting for several minutes and, in rare cases, up to an hour. This disorder is also present in animals. Below is a short video describing how narcolepsy affects the dog Rusty.
Episodes of narcolepsy occur during periods of strong emotion, such as surprise, excitement, joy and even during laughter. In the video the dog Rusty runs around and is seemingly enjoying himself and suddenly he falls asleep in mid run. This is not uncommon for Rusty since he suffers from narcolepsy.
Unlike regular sleep, where REM takes more than an hour to occur, those who suffer from narcolepsy reach REM sleep within minutes of an episode. This may suggest that narcolepsy is caused by a malfunction in the hypothalamus, the location of our "biological clock".
Those who suffer from narcolepsy can also suffer from a similar condition called cataplexy where all of the muscles loose their muscle tone, in other words, you go limp. Cataplexy occurs naturally when someone is in REM sleep, this helps the body relax from all the activity during the previous day. The difference between cataplexy and regular REM sleep is that during episodes of cataplexy the person is completely alert.
In rare cases, narcolepsy can severely impact the lives of those it affects. In one particular case, again a dog, suffers from such severe narcolepsy that it is difficult for him to stay awake all day long.
Since humans and animals can both suffer from narcolepsy, does this mean that other mental disorders such as chronic depression, schizophrenia, and bipolar disorder are also present in animals?