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% D 9 -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. Neuropsychopharmacology (2005) 30, 800-809.

The Effects of Low Doses of Δ-9 Tetrahydrocannabinol on Reinforcement Processing in the Risky Decision-Making of Young Healthy Adults

“…Previous studies also suggest that altered choices following THC administration reflects changed processing of their consequences (Lane et al, 2005b); however, our data indicate that THC can also affect processing of reinforcement information while individuals deliberate between risky options. The subsidiary finding that THC administration speeded responses to gambles with large compared to small gains, while placebo retarded such responses, provides some limited confirmation of the predictionFbased upon evidence that CB 1 activation enhances reward-related processing (Gardner et al, 1988;Gardner and Lowinson, 1991)Fthat THC intake will potentiate attention towards appetitive cues during risky choice.…”

“…Studies with operant schedules have suggested that THC affects decisionmaking in the former situation (Lane et al, 2005b); the present results suggest that these effects of THC may generalize to situations where the choices are quite precisely specified, perhaps involving other cognitive sequelae of THC intake. Finally, operant studies of choice behavior following THC administration have also noted that response rates are inevitably reduced alongside any changes in the selection of certain choices over others.…”

“…Effective choice depends upon balancing these motivational states in order to select a response most consist with current behavioral objectives. Two recent studies of the effects of THC on choice behavior, using concurrent (random and variable ratio) operant schedules suggest that THC may induce risktaking behavior by altering sensitivity to reinforcement and promoting a tendency to continue choosing risky options (Lane and Cherek, 2002;Lane et al, 2005b). The present results add to this picture by providing at least some support for these suggestions and by demonstrating that low doses of THC (sublingually administered) can produce relatively complex effects that might, in different ways, inhibit or promote risky behavior.…”

“…Second, Lane et al (2005b) examined responding on two concurrently available variable ratio schedules, again delivering monetary reward. One option (labeled the 'nonrisky' option) delivered a small certain gain with a probability of 1.0 (expected value ¼ $1.12); the other option (labeled the 'risky' option) delivered larger gains and losses with a probability of 0.5 (expected value ¼ $0).…”

Activation of cannabinoid system in anterior cingulate cortex and orbitofrontal cortex modulates cost-benefit decision making

“…There is considerable evidence implicating the use of various cannabis derivatives in altered cognition and decision making, including risk taking behavior, irrational (or excessive) gambling, as well as impulsive and apathetic patterns of choice. This evidence comes mainly from human studies (Dougherty et al 2013;Grant et al 2012;Hermann et al 2009;Lane et al 2005;Moreno et al 2012;Solowij et al 2012;Whitlow et al 2004) and related work in animals (Boomhower et al 2013;Egerton et al 2006;Egerton et al 2005;Mishima et al 2002) that largely concurs with the results of the human studies. The role of cannabinoid signaling in decision-making pathways and the involvement of cannabinoid receptors in frontal cortical circuits of decision making have not received much attention to date.…”