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Traci Speed, M.D., Ph.D., Thomas Sedlak, M.D., Ph.D.
Hallucinations is a topic covered in the Johns Hopkins Psychiatry Guide.

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  • An hallucination is a perception without a stimulus.
    • With true hallucinations, the individual is convinced of the reality of the experience.
  • A true hallucination must be differentiated from:
    • Illusion - a misinterpretation of a stimulus (e.g., a crack on the floor is misperceived as a snake)
    • Pseudohallucination - occurs in inner subjective space (e.g., heard in one’s thoughts, not perceived as auditory, does not come through the ears)
    • Vivid imagery – increased imagination or mental images
  • Hallucinations can occur in any of the five senses (auditory, visual, olfactory, gustatory, and/or tactile).
    • Auditory hallucinations are the most common.
  • Hallucinations are not pathognomic for any specific psychiatric illness, including schizophrenia[1].
  • Hypnagogic and hypnopompic hallucinations can occur in healthy people when falling asleep and awakening, respectively.

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Last updated: September 3, 2017


Speed, Traci, and Thomas Sedlak. "Hallucinations." Johns Hopkins Psychiatry Guide, 2017. Johns Hopkins Guide, www.hopkinsguides.com/hopkins/view/Johns_Hopkins_Psychiatry_Guide/787023/all/Hallucinations.
Speed T, Sedlak T. Hallucinations. Johns Hopkins Psychiatry Guide. 2017. https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_Psychiatry_Guide/787023/all/Hallucinations. Accessed August 19, 2019.
Speed, T., & Sedlak, T. (2017). Hallucinations. In Johns Hopkins Psychiatry Guide. Available from https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_Psychiatry_Guide/787023/all/Hallucinations
Speed T, Sedlak T. Hallucinations [Internet]. In: Johns Hopkins Psychiatry Guide. ; 2017. [cited 2019 August 19]. Available from: https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_Psychiatry_Guide/787023/all/Hallucinations.
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TY - ELEC T1 - Hallucinations ID - 787023 A1 - Speed,Traci,M.D., Ph.D. AU - Sedlak,Thomas,M.D., Ph.D. Y1 - 2017/09/03/ BT - Johns Hopkins Psychiatry Guide UR - https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_Psychiatry_Guide/787023/all/Hallucinations DB - Johns Hopkins Guide DP - Unbound Medicine ER -