Sleep paralysis - Your body is paralyzed during REM, your body can't even stand (This is why sleep walking happen in other stages of sleep). Sometimes does the body fails to turn on your muscles immediately after REM. Normally this condition lasts only a few seconds, but sometimes can it go on for minutes, which causes a very scary feeling. But just remain calm, it will pass. And it is not at all dangerous. You should also know that sleep paralysis is great for leaving your body. Again, leaving your body is not dangerous either.
Sleep walking - The body is paralyzed during REM, so sleep walking occurs in other stages of sleep. It is quite common among children, and can be quite confusing if you find yourself in other places than your bed when you wake up. People have even managed to lock themselves outside their own house. You can dream in other stages than REM, but these dreams are much less vivid.
Sleep talking - Your whole body is normally paralyzed during REM. Your senses remain active, and sometimes it happens that you partly act out your dream. So you may talk while sleeping if your muscles aren't fully paralyzed. We know that we can dream in non-REM sleep, maybe not as vivid, but enough to talk. Most sleep talking occurs in non-REM. In a Lucid Dream can you also command yourself to talk while dreaming.
Narcolepsy - A chronic sleep disorder with no known cause. Its onset can occur at any time throughout life, but its peek onset is during the teen years. The main characteristic of narcolepsy is excessive and overwhelming daytime sleepiness, even after adequate nighttime sleep.
A person with narcolepsy is likely to become drowsy or to fall asleep, often at inappropriate times and places. Daytime sleep attacks may occur with or without warning and may be irresistible. They may also experience periods of catalepsy, temporary decrease or loss of muscle control, especially when getting excited. Hypnagogic hallucinations, vivid, often frightening, dream-like experiences, occur while falling asleep or waking up. Sleep paralysis, temporary inability to talk or move when falling asleep or waking up. It may last a few seconds to minutes. In addition, nighttime sleep may be fragmented with frequent awakenings. Daytime sleepiness, sleep paralysis, and hypnagogic hallucinations can also occur in people who do not have narcolepsy. If sufficiently troublesome can be reduced significantly in some people with Tricyclic antidepressants (eg. Imipramine), which suppress REM sleep.
Dreamland psychic \ Sleeps \ Sleep Disorders