Hallucinations can occur quite naturally without the use of psychotropic drugs such as peyote or LSD. We all have the innate ability to suffer from hallucinations and, according to Freud, one of the definitions of a dream is precisely its hallucinogenic quality. Whilst asleep, we can create full sensory, vocal and emotional experiences in our dreams that most of us believe are real at the time. A waking hallucination is merely an experience of a dream occurring with our eyes open. The voices heard and images seen, although appearing outside of us, are no more exterior than the images in our dreams.
The hypnagogic state is that state between being awake and falling asleep during which the mind is most receptive to ideas, images, sounds, feelings, impressions and intuition. It also the time when people are most likely to see ghostlike figures. (It should not be confused with the hypnopompic state, which is a transition state of semi-consciousness between sleeping and waking.) Some dream experts believe that the sketchy imagery typical of these states can be helpful to the individual in terms of self-understanding. Images are often presented through the individual’s own set of symbols and once interpreted symbols can provide answers to problems and even alert one to future events.
Some believe that taking the time to record these images, feelings and sounds can be just as helpful as recording dream imagery.... The Element Encyclopedia