Drug and alcohol dependence
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Drug Alcohol Depend · Jun 2000
Randomized Controlled Trial Clinical TrialAntinociceptive, subjective and behavioral effects of smoked marijuana in humans.
The purpose of this study was to determine whether marijuana produced dose-dependent antinociception in humans and, if so, whether endogenous opiates modulate this effect. A total of five male regular marijuana users participated in three test sessions during which they smoked cigarettes containing 0% (placebo) and 3. 55% Delta(9)-tetrahydrocannabinol (Delta(9)-THC) (active). Each of four controlled smoking bouts per session, spaced at 40-min intervals, consisted of nine puffs from active and placebo cigarettes (three cigarettes, three puffs per cigarette, one puff per min). ⋯ Before smoking, between smoking bouts and postsmoking, participants completed an assessment battery that included antinociceptive (finger withdrawal from radiant heat stimulation), biological, subjective, observer-rated signs and performance measures. Marijuana produced significant dose-dependent antinociception (increased finger withdrawal latency) and biobehavioral effects. Naltrexone did not significantly influence marijuana dose-effect curves, suggesting no role of endogenous opiates in marijuana-induced antinociception under these conditions.