, Volume 107, Issue 2–3, pp 255–262

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

  • L. D. Chait
  • James P. Zacny
Original Investigations

DOI: 10.1007/BF02245145

Cite this article as:
Chait, L.D. & Zacny, J.P. Psychopharmacology (1992) 107: 255. doi:10.1007/BF02245145


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.

Key words

Human Marijuana THC Subjective effects Reinforcing effects Self-administration Route of administration 

Copyright information

© Springer-Verlag 1992

Authors and Affiliations

  • L. D. Chait
    • 1
  • James P. Zacny
    • 1
  1. 1.Drug Abuse Research Center, Department of Psychiatry, The Pritzker School of MedicineThe University of ChicagoChicagoUSA

Personalised recommendations