Discriminative stimulus and subjective effects of smoked marijuana in humans.
L D Chait, S M Evans, K A Grant, J B Kamien, C E Johanson, C R Schuster
Psychopharmacology 1988 DOI: 10.1007/bf00176846 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental drug discrimination study Peer reviewed |
|---|---|
| Population | Marijuana smokers |
| Dose | 2.7% delta 9-THC, 0.9% delta 9-THC, 1.4% delta 9-THC, 0.0% delta 9-THC |
| Measures | discrimination responding, standardized mood questionnaires, expired air carbon monoxide (CO), heart rate |
| Topics | Cannabis |
| Key findings | Smokers readily learned to discriminate marijuana containing 2.7% delta 9-THC from THC-free placebo cigarettes. The discriminative stimulus effects had a rapid onset, appearing within 90 seconds, and were dose dependent: 0.9% THC produced primarily placebo-appropriate responding, while 1.4% THC produced 100% drug-appropriate responding. Active marijuana also increased heart rate and altered eight mood scales. |
Abstract
The discriminative stimulus (DS) effects of smoked marijuana were studied by training marijuana smokers to discriminate between the effects of marijuana containing 2.7% delta 9-THC (M) and marijuana containing 0.0% delta 9-THC (P). In addition to measures of discrimination responding, subjective effects were assessed with standardized mood questionnaires. The post-smoking increase in expired air carbon monoxide (CO) level was used as an index of smoke inhalation. Relative to P cigarettes, M cigarettes increased heart rate and produced changes on eight mood scales. M cigarettes were rated as harsher and more potent than P cigarettes, and produced lower levels of CO than P cigarettes. The P--M discrimination was readily acquired by most subjects. The DS effects of marijuana showed a rapid onset, appearing within 90 s from the beginning of smoking. The DS effects were dose dependent, with 0.9% delta 9-THC marijuana producing primarily placebo-appropriate discrimination responding, and 1.4% delta 9-THC marijuana producing 100% drug-appropriate responding. This experimental paradigm could be used to determine whether the DS effects of smoked marijuana would generalize to those of other psychoactive drugs.