Skip to main content

Hallucinatory altered states of consciousness


Altered states of consciousness (ASC), especially hallucinatory ones, are philosophically and scientifically interesting modes of operation of the mind–brain complex. However, classical definitions of ASC seem to capture only a few common characteristics of traditionally regarded phenomena, thus lacking exact classification criteria for assessing altered and baseline states. The current situation leads to a priority problem between phenomena-based definitions and definition-based phenomena selection. In order to solve the problem, this paper introduces a self-mapping procedure that is based on a three-part analysis on certain aspects of hallucinatory altered consciousness. Starting with commonalities found in current definitions of ASC, issues with self-evaluation, sources of data, and baseline comparison are analyzed first. Next, the concept of alterations is examined with respect to temporal dynamics, change mechanisms, and mental subsystems. Finally, hallucinatory phenomena are discussed regarding various definitions, the relationship between “external” and “internal,” and the “trueness” issue of hallucinations. Conclusive to the analysis above, a technically based working definition of ASC and a stepwise operationalization procedure are also proposed.

This is a preview of subscription content, access via your institution.


  • Aleman, A., & Larøi, F. (2008). Hallucinations: The science of idiosyncratic perception. Washington: American Psychological Association.

    Book  Google Scholar 

  • Dittrich, A., von Arx, S., & Staub, S. (1985). International study on altered states of consciousness (ISASC). Summary of the results. German Journal of Psychology, 9, 319–339.

    Google Scholar 

  • Esquirol, J. E. D. (1845/1965). Mental maladies—A treat on insanity. New York: Hafner.

    Google Scholar 

  • Farthing, G. W. (1992). The psychology of consciousness. Englewood Cliffs: Prentice-Hall.

    Google Scholar 

  • ffytche, D. (2008). The hodology of hallucinations. Cortex, 44(8), 1067–1083.

    Article  Google Scholar 

  • Hobson, J. A. (2002). The dream drugstore: Chemically altered states of consciousness. Cambridge: MIT Press.

    Google Scholar 

  • Hobson, J. A. (2007). Normal and Abnormal States of Consciousness. In M. Velmans & S. Schneider (Eds.), The Blackwell companion to consciousness. Oxford: Blackwell Publishing.

    Google Scholar 

  • Horowitz, M. (1975). Hallucinations: An information-processing approach. In R. Siegel & L. West (Eds.), Hallucinations: Behavior, Experience and Theory. New York: Wiley.

    Google Scholar 

  • James, W. (1902/1994). The varieties of religious experience: A study in human nature. New York: Modern Library.

    Google Scholar 

  • Mortimer, A. M., & McKenna, P. J. (1994). Levels of explanation: Symptoms, neuropsychological deficit and morphological abnormalities in schizophrenia. Psychological Medicine, 24, 541–545.

    Article  Google Scholar 

  • Nagel, T. (1974). What it is like to be a bat? The Philosophical Review, 83(4), 435–450.

    Article  Google Scholar 

  • Nichols, D. E. (2004). Hallucinogens. Pharmacology & Therapeutics, 101, 131–181.

    Article  Google Scholar 

  • Revonsuo, A. (2006). Inner presence: Consciousness as a biological phenomenon. Cambridge: MIT Press.

    Google Scholar 

  • Shanon, B. (2003). Hallucinations. Journal of Consciousness Studies, 10(2), 3–31. Imprint.

    Google Scholar 

  • Strassman, R., Qualls, C. R., Uhlenhuth, E. H., & Kellner, R. (1994). Dose-response study of N,N-dimethyltryptamine in humans. II. Subjective effects and preliminary results of a new rating scale. Archives of General Psychiatry, 51, 98–108.

    Google Scholar 

  • Tart, C. T. (1975). States of consciousness. New York: E.P. Dutton.

    Google Scholar 

  • Vaitl, D., Birbaumer, N., Gruzelier, J., Jamieson, G. A., Kotchoubey, B., Kubler, A., et al. (2005). Psychobiology of altered states of consciousness. Psychological Bulletin, 131(1), 98–127.

    Article  Google Scholar 

  • VandenBos, G. R. (Ed.). (2007). APA dictionary of psychology. Washington: American Psychological Association.

    Google Scholar 

  • Vollenweider, F. X., & Geyer, M. A. (2001). A systems model of altered consciousness: Integrating natural and drug-induced psychoses. Brain Research Bulletin, 56(5), 495–507.

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Levente Móró.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Móró, L. Hallucinatory altered states of consciousness. Phenom Cogn Sci 9, 241–252 (2010).

Download citation

  • Published:

  • Issue Date:

  • DOI:


  • Altered states of consciousness
  • Hallucinations