Effects of THC and Alcohol on Driving Performance

Lakehead University

Status and phase: Withdrawn; Phase 4

Conditions: Cannabis; Accident, Traffic; Alcohol Drinking

Treatments: Drug: THC 5; Drug: THC 0; Other: BAC .049; Drug: THC 10; Other: BAC 0; Other: BAC .025

Study type: Interventional

Funder types: Other

Identifiers

NCT03555968

2018502

Details and patient eligibility

About

Low blood concentrations of THC and alcohol appear to have a minimal effect on driving performance.However, there is a gap in the literature about the combined effects of THC and alcohol. There is little empirical evidence to determine whether the combination of THC and alcohol could be additive or multiplicative. This issue is particularly important when dealing with concentrations that are just below legal thresholds - it is important to identify if someone who may have consumed cannabis and alcohol, in quantities that do not exceed legal thresholds, may nonetheless be impaired to drive. Answering this question requires more research on the combined effects of THC and alcohol under tightly controlled experimental conditions. Hence, the purpose of this study is to determine the additive (or multiplicative) effect of standardized low doses of cannabis, in combination with low-doses of alcohol, on a number of outcome measures related to driving. The investigators will focus specifically on the effect of low blood concentrations of THC (0, 125, and 250 µg/kg) alone and in combination with low blood concentrations of alcohol (BAC 0%, .025%, and .049%). They shall determine the combined effect of THC and alcohol on physiological, cognitive, subjective measures of impairment, and simulated driving. This study will focus on younger adults because they have higher impaired driving rates than other age groups. As a secondary aim of the study, the investigators will examine whether previous driving and drug use history are correlated with driving decisions during the simulated drive and subjective measures. This study will contribute to the evidence base informing legislation, policy making, and law enforcement. This study is particularly timely given upcoming changes in legislation about cannabis, and because the combination of THC and alcohol, even below legal thresholds, may lead to impaired driving and crashes.

Sex: All

Ages: 19 to 25 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• BMI >18 and <30
• valid G2 or G Ontario driver's license
• live on-campus or within 15 minutes drive of campus
• speak fluent English

Exclusion criteria

• history of cardiovascular or psychiatric disorders
• current use of psychoactive medication
• current drug or alcohol abuse problem
• positive drug screen
• BAC level > .000%

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Factorial Assignment

Masking: Triple Blind

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0 participants in 9 patient groups, including a placebo group

THC 0 + BAC 0

Placebo Comparator group

Description:

Participants will receive 0mg of THC in combination with blood alcohol concentrations of .000%.

Treatment:

Other: BAC 0

Drug: THC 0

THC 5 + BAC 0

Experimental group

Description:

Participants will receive 5mg of THC in combination with blood alcohol concentrations of .000%.

Treatment:

Other: BAC 0

Drug: THC 5

THC 10 + BAC 0

Experimental group

Description:

Participants will receive 10mg of THC in combination with blood alcohol concentrations of .000%.

Treatment:

Other: BAC 0

Drug: THC 10

THC 5 + BAC .025

Experimental group

Description:

Participants will receive 5mg of THC in combination with blood alcohol concentrations of .025%.

Treatment:

Other: BAC .025

Drug: THC 5

THC 10 + BAC .025

Experimental group

Description:

Participants will receive 125 µg/kg of THC in combination with blood alcohol concentrations of .025%.

Treatment:

Other: BAC .025

Drug: THC 5

THC 0 + BAC .049

Experimental group

Description:

Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .049%.

Treatment:

Other: BAC .049

Drug: THC 10

Other: BAC .025

Drug: THC 0

THC 5 + BAC .049

Experimental group

Description:

Participants will receive 5mg of THC in combination with blood alcohol concentrations of .049%.

Treatment:

Other: BAC .049

Drug: THC 5

THC 10 + BAC .049

Experimental group

Description:

Participants will receive 10mg of THC in combination with blood alcohol concentrations of .049%.

Treatment:

Other: BAC .049

Drug: THC 5

THC 0 + BAC .025

Experimental group

Description:

Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .025%.

Treatment:

Other: BAC .049

Drug: THC 10

Other: BAC .025

Drug: THC 0