Reinforcing and subjective effects of oral Δ9-THC and smoked marijuana in humans

Abstract

The reinforcing and subjective effects of oral delta-9-tetrahydrocannabinol (THC) and smoked marijuana were studied in two groups of regular marijuana users. One group (N = 10) was tested with smoked marijuana and the other (N = 11) with oral THC. Reinforcing effects were measured with a discrete-trial choice procedure which allowed subjects to choose between the self-administration of active drug or placebo on two independent occasions. Subjective effects and heart rate were measured before and after drug administration. Smoked active marijuana was chosen over placebo on both choice occasions by all subjects. Similarly, oral THC was chosen over placebo on both occasions by all but one subject. Both active drug treatments produced qualitatively and quantitatively similar subjective effects, and both significantly increased heart rate, although the time course of effects differed substantially between the two treatments. The results demonstrate that both smoked marijuana and oral THC can serve as positive reinforcers in human subjects under laboratory conditions. The experimental paradigm used here should prove useful for identifying factors that influence the self-administration of marijuana and other cannabinoids by humans.

The Psychotomimetic Effects of Intravenous Delta-9-Tetrahydrocannabinol in Healthy Individuals: Implications for Psychosis

“…While cannabis has been reported to impair several aspects of cognitive functioning in a dose-related manner, deficits in verbal recall appear to be the most consistent finding in laboratory studies (Belmore and Miller, 1980;Chait and Zacny, 1992;Curran et al, 2002;Hart et al, 2001;Heishman et al, 1997Heishman et al, , 1990Hooker and Jones, 1987;Marks and MacAvoy, 1989;Miller and Branconnier, 1983;Miller et al, 1977). Our data are consistent with these effects.…”

Cannabinoid Modulation of Amygdala Reactivity to Social Signals of Threat in Humans

“…The moderate dose of THC increased ratings of "drug high" and "feel drug" but, consistent with what has been reported previously, did not increase feelings of anxiety (Chait and Zacny, 1992;Wachtel et al, 2002). Thus, the drug attenuated threat-related amygdala reactivity without concurrent observable changes in anxiety.…”

Smoked cannabis for chronic neuropathic pain: a randomized controlled trial

“…22 The items "high," "relaxed," "stressed," and "happy" were measured using a 100-mm visual analogue scale (0 = not at all, 10 = extremely). [23][24][25] Potency assessments were conducted by asking participants on the fifth day of each period to guess which potency they had received. At the end of the trial, participants were asked to guess the order in which they received the treatments.…”