IntroductionA wide range of fungi and medicinal herbs, rich in hallucinogenic substances and widely used for mystic and medicinal purposes, can give rise to neurotoxic symptoms.DevelopmentWe review the toxic syndromes that can arise from the ingestion of hallucinogenic fungi, cacti and plants, together with descriptions of cases of acute poisoning resulting ...
Historically, states of intoxication--like dreams and madness--are seen in either one of two opposed ways. The intoxicated are either "possessed" or "under the influence" of an external agency, or revealing hidden feelings or truths (in vino veritas). Along the same lines, artists who worked during LSD, mescalin or psilocybin intoxication often refer to feel...
Many observers see geometric visual hallucinations after taking hallucinogens such as LSD, cannabis, mescaline or psilocybin; on viewing bright flickering lights; on waking up or falling asleep; in "near-death" experiences; and in many other syndromes. Klüver organized the images into four groups called form constants: (I) tunnels and funnels, (II) spirals, ...
BackgroundDuring the 1990s, rates of nonmedical drug use among adolescents escalated. We assessed data from 5 cycles of the Ontario Student Drug Use Survey for overall trends in the proportion of students reporting illegal drug use between 1991 and 1999.MethodsThe survey is a repeated, cross-sectional, 2-stage cluster-design survey of students enrolled in gr...
BackgroundEvery 2 years, the Addiction Research Foundation of Ontario, a division of the Centre for Addiction and Mental Health, sponsors the Ontario Student Drug Use Survey. The results of the surveys conducted in 1995 and 1997 are presented here and compared with results from the early 1990s.MethodsQuestionnaires were completed by 3870 and 3990 Ontario pub...
We conducted a random survey of illicit drug use by undergraduate students at a private southern university in 1990 and compared the results with results from a similar 1986 survey of that college's student population. During the 4 years since the first study, the prevalence of cocaine use declined from 39% to 21%, and use of traditional amphetamines decline...
Hallucinogenic drugs (psychedelics, e.g. Psilocybin, Mescaline, LSD) induce in humans qualitatively altered states of consciousness (ASC), which can be used as experimental models for endogenous psychosis. However, some researchers claim that these ASCs are not appropriate models for schizophrenia. We report two clinical cases of acute endogenous psychoses d...
A dosage regimen of lysergic acid diethylamide (LSD) that reliably produces behavioral tolerance in rats was evaluated for effects on neurotransmitter receptor binding in rat brain using a variety of radioligands selective for amine receptor subtypes. Daily administration of LSD [130 micrograms/kg (0.27 mumol/kg) intraperitoneally (IP)] for 5 days produced a...
Hallucinogenic drugs are unique in that they produce the desired hallucinogenic effects at what are considered non-toxic doses. The hallucinogenic drugs can be categorised into 4 basic groups: indole alkaloid derivatives, piperidine derivatives, phenylethylamines and the cannabinols. The drugs reviewed include lysergic acid diethylamide (LSD), phencyclidine ...
In order to further evaluate the extent to which particular 5-HT receptor subtypes (5-HT1, 5-HT2) might be involved in the behavioral effects of hallucinogenic drugs, rats were trained to discriminate mescaline (10 mg/kg i.p.) from saline and were given substitution (generalization) and combination (antagonism) tests with putatively selective serotonergic an...
The stimulus properties of 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA) and several related compounds were compared to those of (+)-lysergic acid diethylamide (LSD) and mescaline (3,4,5-trimethoxyphenylethylamine) in a two-lever, water-reinforced, drug discrimination task. In animals trained to discriminate LSD (0.08 mg/kg) f...
Tryptamine produces pharmacologic effects in man and the chronic spinal dog which are similar to those produced by LSD, mescaline, psilocin, DMT, DOM and DOB. These effects include tachycardia, tachypnea, mydriasis, hyperreflexia, behavioral changes and in man, hallucinations. Chronic spinal dogs treated chronically with LSD became tolerant to its ability to...
The nature of the stereochemistry and aromatic ring substituents and their importance to biological activity for phenethylamine-type hallucinogens is presented. The possibility of a hydrophobic site to bind to the 4-substituent and its likely geometry is described. A brief discussion of the structure-activity relationships for tryptamines such as psilocin an...
Previous studies from our laboratory have demonstrated that there are a number of important dissociations between the effects of hallucinogenic drugs on the activity of serotonin-containing dorsal raphe neurons and behavior in freely moving cats. In the present study, we extended this analysis to serotonergic units in the nucleus centralis superior (NCS) and...
Fifteen rats were trained to discriminate between the tryptamine hallucinogen psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine; 1.0 mg/kg) and saline in a two-lever choice task. Dose-response and time-response curves were obtained. The psilocybin cue generalized to psilocin (the dephosphorylated congener of psilocybin) and to the prototypical indoleamine h...
Low intravenous doses of the hallucinogen d-lysergic acid diethylamide (LSD) markedly suppress the discharge of serotonin (5-HT)-containing neurons in the dorsal raphe nucleus of the rat. Microiontophoretically applied LSD also inhibits the firing of 5-HT neurons, indicating that the inhibitory effect is mediated directing on 5-HT neurons. Forebrain neurons ...
Psychotic states are mimicked by the use of many drugs including amphetamines, cannabis, lysergic acid diethylamide, psilocybin, mescaline, isoniazid, and L-dopa. A paranoid psychotic picture in a clear sensorium is characteristic of amphetamine psychosis. In developing countries, malaria among other diseases is a frequent indicator of chloroquine administra...
The hypothesis that the action of hallucinogenic drugs is mediated by a depression of the activity of brain serotonergic (raphe) neurons was tested by examining the behavioral effects of several hallucinogenic drugs while concurrently monitoring the activity of raphe neurons in freely moving cats. LSD produced a dose-dependent decrease in raphe unit activity...
