Sleep Paralysis (SP) and its associated hypnagogic and hypnopompic hallucinations, along with cataplexy and daytime sleepiness, have traditionally been considered among the “narcoleptic tetrad.”

Summary Hallucinations can be a sign of a mental health illness, but they do not always mean a person is unwell. Hallucinations are, in fact, relatively common. One 2015 study from Europe found.

There are many types of hallucinations.They can be visual (sight hallucinations), auditory (sound hallucinations), olfactory (smell hallucinations), gustatory (taste hallucinations), or tactile.