Examine the Feasibility of a Standardized Field Test for Marijuana Impairment: Laboratory Evaluations

Examine the Feasibility of a Standardized Field Test for Marijuana Impairment: Laboratory Evaluations

Examine the Feasibility of a Standardized Field Test for Marijuana Impairment: Laboratory Evaluations

National Highway Traffic Safety Administration (NHTSA), Hartford Hospital, Montana State University, Maastricht University, The Mind Research Network, National Institute on Drug Abuse (NIDA)

Marijuana is one of the most widely used substances. This study will characterize the persistence of cannabis' (CNB's) acute effects on cognitive test performance and simulated driving over a several hour time period. The data obtained from simulated driving, cognitive tests, and biological assays of THC will be used in analyses aimed at identifying what tests or combination of tests predict both recent use and driving impairment risk. Eligible participants will undergo a full day screening visit, if still eligible they will come to Hartford Hospital in Hartford, Connecticut to take part in the full study. Participation requires overnight stays between each of the five study visits. On each of the study days participants are dosed with either a low dose of THC marijuana, a high dose of THC marijuana or placebo marijuana, (the low and high doses are repeated once each, order in which the study drug is given is double blind and chosen at random.)

This responds to NHTSA's request with a proposal to increase our understanding of smoked cannabis' (CNB's) acute effects on cognition and simulated driving performance, the persistence of these deficits over the hours after use, and the influence of prior experience with CNB on these effects. The project also will link an extensive literature on CNB's effects on laboratory cognitive tests to simulated driving performance for the first time, providing a crucial validation of CNB's neurofunctional effects identifying maximally relevant candidate measures for field sobriety tests. To this goal, the proposed study was based upon a careful and thorough review of the scientific literature describing CNB effects on cognitive test performance and driving, as well as current state-of-knowledge on the sensitivity of biological assays for identifying recent CNB use. The study will carefully characterize the persistence of CNB's acute effects on cognitive test performance and driving over a several-hour time span. This will allow us to identify the point at which any effects of CNB intoxication on cognitive tests and driving performance cannot be distinguished from normal, i.e., the first step towards establishing standards for legal and social policy. The data obtained from simulated driving, cognitive tests, and biological assays of THC will be used in analyses aimed at identifying what tests or combination of tests predict both recent use and driving impairment risk. Participants

People who use marijuana regularly will be given a low dose THC marijuana, high dose THC marijuana and placebo marijuana, in a randomized order, at the five study visits.

People who use marijuana occasionally will be given a low dose THC marijuana, high dose THC marijuana and placebo marijuana, in a randomized order, at the five study visits.

Dosing via vaporized marijuana using a lower concentration of THC, participants receive this dose on two of the five study visits.

Dosing via vaporized marijuana using a higher concentration of THC, participants receive this dose on two of the five study visits.

Dosing via vaporized marijuana with no THC, participants receive this dose on one of the five study visits.

The Cogstate 1-back/2-back task assesses working memory, it will be administered prior to dosing and at various time points after dosing.

The Cogstate Card Learning task assesses visual memory, it will be administered prior to dosing and at various time points after dosing.

The Cogstate Groton Maze Learning task assesses spatial learning and memory, it will be administered prior to dosing and at various time points after dosing.

The Cogstate Social/Emotional Cognition task assesses emotional processing, it will be administered prior to dosing and at various time points after dosing.

The Alertmeter task assess visual judgment and alertness, it will be administered prior to dosing and at various time points after dosing.

The Time Estimation Task assesses timing, it will be administered prior to dosing and at various time points after dosing.

The Stop Signal Reaction Time Task assesses inhibitory processing, it will be administered prior to dosing and at various time points after dosing.

The Critical Tracking Task assesses hand eye coordination and visuomotor tracking, it will be administered prior to dosing and at various time points after dosing.

The ANAM Pursuit Tracking Task assesses hand eye coordination, it will be administered prior to dosing and at various time points after dosing.

The Finger to Nose Task assesses general motor coordination, it will be administered prior to dosing and at various time points after dosing.

The One Leg Stand Task assesses general motor coordination, it will be administered prior to dosing and at various time points after dosing.

The Line Walking/Months Backwards Task assesses general motor coordination plus distraction, it will be administered prior to dosing and at various time points after dosing.

The Time Reproduction Task assesses general motor coordination plus timing, it will be administered prior to dosing and at various time points after dosing.

Blood samples with be collected at 8 times throughout each day to assess for changes of THC and its metabolite levels.

Baseline and post drug administration at: 5 min, 20 min, 1 hr 10 min, 1 hr 45 min, 2 hrs 30 min, 4 hrs, and 6 hrs 30 min.

Oral fluid samples with be collected at 8 times throughout each day to assess for changes of THC and its metabolite levels.

Baseline and post drug administration at: 5 min, 20 min, 1 hr 10 min, 1 hr 45 min, 2 hrs 30 min, 4 hrs, and 6 hrs 30 min.

Change in concentration of THC/metabolites in oral fluid tested using Quantisal Oral Fluid Collection devices.

Oral fluid samples with be collected at 8 times throughout each day to assess for changes of THC and its metabolite levels.

Baseline and post drug administration at: 5 min, 20 min, 1 hr 10 min, 1 hr 45 min, 2 hrs 30 min, 4 hrs, and 6 hrs 30 min.

The Road Tracking Task measures operational control of the vehicle. Operational control is measured by standard deviation of lane position from the center point of the lane.

The Car Following Task measures tactical control of the vehicle. Tactical control of the vehicle is measured by following distance from a lead vehicle.

The Gap Acceptance Task measures strategic control of the vehicle. Strategic control of the vehicle is measured by size of headway gaps that the participant chooses in pulling out into oncoming traffic to overtake a stopped car.

Inclusion Criteria: Must have a current driver's license Have used marijuana before Right handed Exclusion Criteria: Females who are pregnant or breast feeding Any serious medical, or neurological disorder Any psychiatric disorder No major head traumas