Anomalous bodily-self experiences among recreational ketamine users

• Published in: Cognitive neuropsychiatry Vol. 17; no. 5; pp. 415 - 430
• Main Authors: Wilkins, Leanne K., Girard, Todd A., Cheyne, J. Allan
• Format: Journal Article
• Language: English
• Published: Hove Taylor & Francis Group 01-09-2012; Psychology Press; Taylor & Francis Ltd
• Subjects: Adolescent; Adult; Anesthetics, Dissociative - administration & dosage; Autoscopy; Biological and medical sciences; Body Image - psychology; Brain; Depersonalization - chemically induced; Depersonalization - psychology; Disorders of higher nervous function. Focal brain diseases. Central vestibular syndrome and deafness. Brain stem syndromes; Female; Humans; Illusions - drug effects; Illusions - psychology; Ketamine; Ketamine - administration & dosage; Male; Medical sciences; Models, Psychological; Nervous system (semeiology, syndromes); Neurology; Out-of-body experiences; Street Drugs; Substance-Related Disorders - psychology; Surveys and Questionnaires; Unexplained phenomena; Vestibular-motor hallucinations; Young Adult; Human; Self-consciousness; Nervous system diseases; User; Hallucination; Consciousness impairment; Glutamate receptor; Vestibular-motor hallucinations; Out-of-body experiences; Inner ear; Autoscopy; Ketamine; General anesthetic; Body experience; Body movement; Antagonist; Vestibular system; NMDA receptor; Neurological disorder; Motricity; Recreational drug
• ISSN: 1354-6805; 1464-0619
• DOI: 10.1080/13546805.2012.663162

Introduction. Out-of-body experiences present a unique paradigm to investigate cognitive and neural mechanisms of bodily-self processes and their disorders. Previous work on out-of-body experiences associated with sleep paralysis supported a model in which illusory movement experiences reflect disrupted bodily-self integration generating anomalous vestibular and motor sensations. Further disintegration and progression of the experience may then give rise to out-of-body feelings, which in turn may instigate out-of-body autoscopy.
Methods. The current study assesses the disintegration model through analyses of out-of-body experiences reports from an online survey of individuals reporting recreational ketamine use (n=128) and cross-validation in a sample of nonketamine polydrug users (n=64). Path analyses using intensity and frequency measures of anomalous experiences assess the fit of seven competing models.
Results. The disintegration model (illusory movement → out-of-body feelings → out-of-body autoscopy) emerged as the best fitting model overall and results support full mediation of the relation between illusory movement experiences and out-of-body autoscopy by out-of-body feelings. Moreover, lifetime measures of ketamine use predicted the frequency of illusory movement experiences.
Conclusions. The results corroborate this structural model of out-of-body phenomena and encourage a framework for future studies into aetiological mechanisms of out-of-body experiences to include neurochemical systems.