The mites that cause scabies are tiny parasites, smaller than a pinhead. They are usually picked up by direct skin-to-skin contact with someone who already has scabies, and only very rarely from objects such as clothing or bedding.
The most memorable and emotionally powerful dreams happen during the REM (rapid-eye movement) phase of sleep, which is the stage of sleep when our brains are most similar to a wakeful state.
Nightmare disorder is referred to by doctors as a parasomnia â a type of sleep disorder that involves undesirable experiences that occur while you're falling asleep, during sleep or when you're waking up. Nightmares usually occur during the stage of sleep known as rapid eye movement (REM). You normally go through four to six sleep cycles a night, cycling through the sleep stages in about 90 minutes. Your REM stage lengthens with each cycle, from several minutes in the first cycle to up to an hour in the last. You're more likely to have a nightmare in the second half to the last third of your night.