title: Acute marijuana effects on human risk taking.
abstract: Previous studies have established a relationship between marijuana use and risky behavior in natural settings. A limited number of laboratory investigations of marijuana effects on human risk taking have been conducted. The present study was designed to examine the acute effects of smoked marijuana on human risk taking, and to identify behavioral mechanisms that may be involved in drug-induced changes in the probability of risky behavior. Using a laboratory measure of risk taking designed to address acute drug effects, 10 adults were administered placebo cigarettes and three doses of active marijuana cigarettes (half placebo and half 1.77%; 1.77%; and 3.58% Delta9-THC) in a within-subject repeated-measures experimental design. The risk-taking task presented subjects with a choice between two response options operationally defined as risky and nonrisky. Data analyses examined cardiovascular and subjective effects, response rates, distribution of choices between the risky and nonrisky option, and first-order transition probabilities of trial-by-trial data. The 3.58% THC dose increased selection of the risky response option, and uniquely shifted response probabilities following both winning and losing outcomes following selection of the risky option. Acute marijuana administration thereby produced measurable changes in risky decision making under laboratory conditions. Consistent with previous risk-taking studies, shifts in trial-by-trial response probabilities at the highest dose suggested a change in sensitivity to both reinforced and losing risky outcomes. Altered sensitivity to consequences may be a mechanism in drug-induced changes in risk taking. Possible neurobiological sites of action related to THC are discussed.
authors.affiliation: Department of Psychiatry & Behavioral Sciences, University of Texas Health Science Center, Houston, TX 77030, USA. scott.d.lane@uth.tmc.edu
authors.forename: Scott D
authors.initials: SD
authors.lastname: Lane
authors.forename: Don R
authors.initials: DR
authors.lastname: Cherek
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Tcheremissine
authors.forename: Lori M
authors.initials: LM
authors.lastname: Lieving
authors.forename: Cythia J
authors.initials: CJ
authors.lastname: Pietras
mesh_terms: D000328:Adult; D001921:Brain / Q000187:drug effects* / Q000503:physiopathology; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects; D002755:Choice Behavior / Q000187:drug effects*; D003657:Decision Making / Q000187:drug effects* / Q000502:physiology; D013759:Dronabinol / Q000008:administration & dosage / Q000009:adverse effects*; D004334:Drug Administration Schedule; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000009:adverse effects* / Q000523:psychology*; D011930:Reaction Time / Q000187:drug effects; D012309:Risk-Taking; D012737:Sex Factors
chemical_list: D013759:Dronabinol