Parasomnias are a group of sleep disorders that involve unwanted events or experiences that occur while you are falling asleep, sleeping or waking up. Parasomnias may include abnormal movements, behaviors, emotions, perceptions or dreams. Although the behaviors may be complex and appear purposeful to others, you remain asleep during the event and often have no memory that it occurred. If you have a parasomnia, you may find it hard to sleep through the night.