This experimental study investigated the psychological and physiological sequelae of marijuana intoxication. Ten Wistar rats (5 females and 5 males) were observed before and after varying dosages of marijuana extract were administered to them, based on their body weights and following LD50. Such psychological parameters as memory, anxiety, sleep/wake behaviour, eating behaviour, social interaction, and motor skills of the rats were observed and recorded. It was hypothesised that marijuana would cause physiological, psychological and physical changes in the rats and that these would vary between female and male rats. Findings indicated that onset of intoxication occurred within 45minutes of ingesting the marijuana orally. Marijuana exerted important changes in all six psychophysiological parameters (memory, anxiety, sleep/ wake behaviour, eating behaviour, social interaction, and motor skills). Among other recommendations, subsequent experimental studies should endeavour to account for specific proportions of cannabinoids present in the cannabis strain used. Conducted 2 experiments with a total of 120 males (mean age = 23 yr.) to determine to what extent marihuana intoxication is the result of drug effects, expectancy, social setting, or an interaction of these factors. In Exp. I, Ss 1st swallowed a placebo pill and then smoked either 2 placebo cigarettes or two marihuana cigarettes containing a total of l5 mg. D9-tetrahydrocannabinol (THC). The cigarettes were smoked in a setting designed to either facilitate intoxication (“up night”) or interfere with it (“down night”) through manipulation of S’s expectancy and through modeling. Results indicate that the amount of marihuana smoked impaired cognitive functioning and was rated as more intoxicating than the placebo. Manipulations of setting and belief had no effect. In Exp. II, Ss smoked 2 cigarettes containing either placebo, 7.5 mg. THC, or l5 mg. THC. Ss who smoked placebo cigarettes 1st swallowed a pill containing either 10 or 25 mg. librium (chlordiazepoxide). Ss who smoked cigarettes containing THC received placebo pills. Smoking was done in either “up night” or “down night” contexts. Results suggest that social setting and belief interact with smaller doses of marihuana but not with large doses nor with placebo. (PsycINFO Database Record (c) 2016 APA, all rights reserved). Performance impairment during Δ9-tetrahydrocannabinol (THC) intoxication has been well described in occasional cannabis users. It is less clear whether tolerance develops to the impairing effects of THC in heavy users of cannabis.
