A<unk> , also known as a bad dream, is an unpleasant dream that can cause a strong emotional response from the mind, typically fear but also despair, anxiety or great sadness. However, psychological nomenclature differentiates between<unk> s and bad dreams; specifically, people remain asleep during bad dreams, whereas<unk> s can awaken individuals. The dream may contain situations of discomfort, psychological or physical terror, or panic. After a<unk> , a person will often awaken in a state of distress and may be unable to return to sleep for a short period of time. Recurrent<unk> s may require medical help, as they can interfere with sleeping patterns and cause insomnia.<unk> s can have physical causes such as sleeping in an uncomfortable position or having a fever, or psychological causes such as stress or anxiety. Eating before going to sleep, which triggers an increase in the body's metabolism and brain activity, can be a potential stimulus for<unk> s. The prevalence of<unk> s in children (5–12 years old) is between 20 and 30%, and for adults is between 8 and 30%. In common language, the meaning of<unk>  has extended as a metaphor to many bad things, such as a bad situation or a scary monster or person.
Nightmare
Night terror  Night terror  1
Nightscout
Twilight sleep
Sleep onset
Mental health day
Yawn
Sleep sex