cannabis-induced hallucination

   Cannabis and its various products are known under many names, including bhang, canvas, ganja, grass, grifos, * hashish, Indian hemp, * kif, * marihuana, Mary Jane, pot, reefers, skunk cannabis, stick, and weed. The name cannabis is Latin for canvas or hemp. It comes from the Greek noun kânnabis, which originally may have been a Scythian or Thracian word. It has of old been used to denote three species of herbaceous plants from the Cannabaceae family, i.e. Cannabis sativa, Cannabis indica,andCannabis ruderalis. However, a variety of polymorphous ecotypes and cultivated 'races' are also referred to as cannabis. The leaves and flowers of the pistillate (female) plants of these species contain tetrahydrocannabinol (THC), also known as delta-9-tetrahydrocannabinol and dronabinol. THC is one out of the more than 60 cannabinoids that can be found in cannabis. It is considered the plant's principal psychoactive constituent. Therefore, the concentration of THC is believed to be the main determinant of the strength of cannabis products. THC was isolated from cannabis in 1964 by the group made up of the Israelian scientists Raphael Mechoulam (b. 1930), Yechiel Gaoni, and Habib Edery. The term *hashish is used to denote a preparation composed of the compressed appendages (or trichomes) collected from the cannabis plant. The terms kif, kief, keef, and kef are used to denote a potent cannabis product obtained by removing the loose, dried tri-chomes of cannabis from containers or grinders. The term skunk cannabis refers to a potent crossbreed of C. sativa and C. indica. Cannabis has been used since ancient times as a therapeutic, an * entheogen, and an aphrodisiac, as well as for recreational purposes. The first scientific reports on cannabis appeared in the 1830s. Arguably the most important work from this early period is the book Du Hachisch et de l'Aliénation Mentale by the French alienist Jacques-Joseph Moreau de Tours (1804-1884). It is estimated that today about 4% of the world's adult population use cannabis at least once a year, and that 0.6% use cannabis on a daily basis. Cannabis products are usually administered through smoking. They can also be vaporized, however, or eaten, or drunk in the form of an infusion or tea. The intravenous use ofcannabis products is ineffective, and is therefore uncommon. The minimum amount of THC needed to obtain a discernible psychoactive effect lies around 10 (ig/kg of body weight. This effect is believed to be mediated via the cannabinoid receptor type 1 (CB1), which is distributed throughout the CNS and other parts of the body. This cannabinoid receptor was discovered in or shortly before 1988 by the group of the American molecular pharmacologists William Anthony Devane and Allyn Howlett. The acute effects of cannabis tend to commence several minutes after consumption, reaching their peak some 10-30 min later, and lingering on for several hours. Low doses of THC typically evoke mild euphoria, relaxation, and a disinhibition of social tension. This state is often accompanied by hunger, more specifically a craving for sweets. Other early side effects are thirst, uncontrollable laughter, nausea, vertigo, and dryness of the mouth. Subtle changes in sensory acuity may occur as well (i.e. an increase in the vividness of sight, smell, touch, taste, or hearing), as well as mild formal thought disorders, paranoia, anxiety, and panic feelings. Stronger doses tend to intensify these reactions. The user may experience impairments of concentration and short-term memory, a disorientation in time and place, formal thought disorders, rapid changes of affect, and an altered sense of self-identity. High doses may result in *metamorphopsias, *synaesthesias, *illusions, hallucinations, and * dissociation. The hallucinations occurring in the context of THC intoxication tend to be *visual and/or *auditory in nature. The visual hallucinations are mainly * simple or * geometric in nature, although * complex and even * compound hallucinations are reported as well. Because cannabis acts via its own unique cannabinoid receptor system, and makes use of a unique neurotransmitter (called anandamide), it is considered to constitute a pharmacological class of its own. In the past, cannabis has been classified variously as a narcotic, a sedative, and a *hallucinogen. Because ofits purportedly weak hallucinogenic properties, cannabis has also been classified as a quasi-psychedelic. It can induce severe hallucinatory states, however, especially when relatively high doses of THC are consumed by an individual not accustomed to such doses, and/or when the individual has a heightened vulnerability for * psychosis. Cannabis-induced psychosis is believed to be a relatively infrequent complication of cannabis use. As indicated in the early 1990s by the group of the Dutch psychiatrist Don Linszen, cannabis use would seem to be associated with an earlier onset of psychotic symptoms in individuals diagnosed with schizophrenia. However, the exact relation between cannabis use and prolonged or recurrent psychosis (as in individuals with a clinical diagnosis of *schizophrenia) has not been established with certainty. A person intentionally employing cannabis for the purpose of exploring the psyche may be called a * psychonaut.

   References

   Gaoni, Y., Mechoulam, R. (1964). Isolation, structure and partial synthesis of an active constituent of hashish. Journal of the American Chemical Society, 86, 1646.

   Linszen, D.H., Dingemans, P.M., Lenior, M.E. (1994). Cannabis abuse and the course of recent-onset schizophrenic disorders. Archives of General Psychiatry, 51, 273-279.

   Moreau, J.-J. (1845). Du hachisch et de l'aliénation mentale. Études psychologiques. Paris: Fortin Masson.

   Solowij, N. (1998). Cannabis and cognitive functioning. Cambridge: Cambridge University Press.