Motivational effects of smoked marijuana: Behavioral contingencies and high-probability recreational activities

Richard W. Foltin, Marian W. Fischman, Joseph V. Brady, Thomas H. Kelly, Daniel J. Bernstein, Margaret J. Nellis

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


Fifteen adult male research volunteers, in five groups of three subjects each, lived in a residential laboratory for up to 20 days. All contact with the experimenters was through a networked computer system, and subjects' behaviors were monitored continuously and recorded. During the first part of each day, subjects remained in their private rooms doing planned work activities, and during the remainder of each day, they were allowed to socialize. One or two cigarettes containing active marijuana (1.3-2.7% Δ9-THC) or placebo were smoked during both the private work period and the period of access to social activities. Two- or three-day contingency conditions requiring subjects to engage in a low-probability recreational activity in order to earn time that could be spent engaging in a high-probability recreational activity were programmed during periods of placebo and active marijuana smoking. During placebo administration, the contingency requirement reliably increased the amount of time that subjects spent engaged in the low-probability instrumental activity and decreased the time spent engaged in the high-probability contingent activity. During active marijuana administration, however, the increase in instrumental activity were consistently smaller than observed under placebo conditions. The decreases in high-probability contingent activity were similar across drug conditions. Smoking active marijuana was thus observed to produce instrumental decrements under motivational conditions involving recreational contingencies.

Original languageEnglish
Pages (from-to)871-877
Number of pages7
JournalPharmacology Biochemistry and Behavior
Issue number4
StatePublished - Dec 1989

Bibliographical note

Funding Information:
This research was supported by Grant No. DA-03476 from The National Institute on Drug Abuse and approved by the Johns Hopkins Joint Committee on Clinical Investigation. J.V.B. is the recipient of Research Scientist Award KO5 DA-00018 from The National Institute on Drug Abuse. The assistance of Cleeve Emurian, Jerry Locklee, Jeffrey J. Rachlinski, Andrea J. Rose and Michelle Woodland is gratefully acknowledged. A preliminary report of some of these findings was made at the 1987 meeting of The Committee on the Problems of Drug Dependence.


  • Amotivational syndrome
  • Humans
  • Marijuana
  • Motivation
  • Performance
  • Recreational activity

ASJC Scopus subject areas

  • Biochemistry
  • Toxicology
  • Pharmacology
  • Clinical Biochemistry
  • Biological Psychiatry
  • Behavioral Neuroscience


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