<prompt> Which of the following term denotes a false sensory perception in the absence of an external stimuli?DelusionIllussionHallucinationObsession  <response>: False sensory perception in the absence of an actual external stimuli is a perceptual abnormality called hallucination. Hallucinations are perceived as real by the patient. It can be in different modalities like, sound auditory, taste gustatory, touch tactile, sight visual, smell olfactory and combined multi-modal hallucinations.Ref: Kaplan Sadocks Synopsis of Psychiatry: Behavioral Sciences : By Benjamin J Sadock, M.D, Page 244 