COCAINE HALLUCINOSIS

   The term cocaine hallucinosis refers to the various hallucinatory phenomena associated with the chronic use of cocaine (as in a 'cocaine run' or 'cocaine binge', which are both characterized by the prolonged consumption of high doses of cocaine). The Italian physiologist and medical anthropologist Paolo Mantegazza (1831-1910) has been credited with publishing the earliest known account of cocaine hallucinosis in 1859. The typical *paraesthesias or *formicative hallucinations reported by long-term users of cocaine are referred to as * cocaine bugs, * Magnan's sign, and Magnan-Saury's sign. *Visual, *auditory, *olfactory, *gustatory, and *somatic hallucinations have also been reported in the context of chronic cocaine use, although these tend to arise at the later stages of chronic use. The hallucinations of chronic cocaine use range from simple (i.e. *snow lights, *halos around bright lights) to formed (geometrical patterns, often in black and white, and often composed of straight lines and dots) to complex (such as *lilliputian hallucinations or *zoopsia). * Metamorphopsias are reported as well, including *polyopia, *dysmegalopsia, and *dysmorphopsia. It has been suggested that there may be a typical order of appearance of the various types of hallucinations in cocaine abuse, starting with the tactile sensations of cocaine bugs, which may then develop into *visual hallucinations of bugs or vermin moving about on the skin, within wounds, in the air, on clothing, and in the affected individual's direct environment. Reportedly, these visual hallucinations may develop further into hallucinations depicting individuals, animals, or objects. The mediation of hallucinatory phenomena in chronic cocaine use is associated primarily with central pathophysio-logical mechanisms. It has been suggested, however, that some of the *phosphenes and geometric visual hallucinations may be * entoptic phenomena, arising as a consequence of the increased ocular pressure that may accompany states of cocaine intoxication. As a nosological category, cocaine hallucinosis is classified as a specific type of * hallucinosic syndrome.

   References

   Mantegazza, P. (1975). On the hygienic and medicinal virtues ofcoca.In:The coca leaf and cocaine papers. Edited by Andrews, G., Solomon, D. New York, NY: Harcourt Brace Jovanovich.

   Siegel, R.K. (1978). Cocaine hallucinations. American Journal of Psychiatry, 135, 309-314.