A<unk>  is a perception in the absence of a stimulus that the person may or may not believe is real<unk> s are psychotic symptoms that occur when patients perceive stimuli that do not exist).<unk> s may occur in any sensory modality—visual, auditory, olfactory, gustatory, tactile, proprioceptive, equilibrioceptive, nociceptive, thermoceptive.<unk> s are different from illusions. In an illusory experience, a genuine sensation is attributed to an incorrect cause,  misinterpreting a coat hanging on a door to be an intruder or thinking there is water on a hot road, due to the heat rising from the road.  A delusional perception is where a genuine perception (ie. correctly sensed and interpreted) is given some additional (and typically bizarre) significance. Hypnagogic<unk> s and hypnopompic<unk> s are considered normal phenomena. Hypnagogic<unk> s can occur as one is falling asleep and hypnopompic<unk> s occur when one is waking up.<unk> s may also be associated with drug use (particularly<unk> inogenic drugs), sleep deprivation, psychosis or neurological illness.<unk> s may involve any of the five senses:
Auditory
Gustatory
Olfactory
Tactile
Visual
The most common type of<unk> s are auditory
Patients may either dismiss the<unk>  as being false, or they may identify them to be true
Hallucination
Disgust
Perseveration
Emotional detachment
Jealousy
Automatic behavior
Intrusive thoughts
Euphoria