Combined Alcohol and Cannabis Effects on Skills of Young Drivers

Summary

Alcohol and cannabis are the two most widely used substances of abuse in the world and are the psychoactive substances most often found in seriously and fatally injured drivers. In a recent study, it was observed that individuals who reported both driving under the influence of alcohol (DUIA) and the influence of cannabis (DUIC) experienced collision risk that was nearly 4 times that of individuals who reported driving after using only one of these drugs. Recent research in the United States and Canada indicates that the prevalence of DUIC among young drivers of high school and university age, and young adults is similar to, or higher than, the prevalence of DUIA. This is a serious public health issue, since motor vehicle collisions are the leading cause of death in this age group. Given the frequency with which alcohol and cannabis are consumed together, it is important to understand their combined effects on driver behaviour. The current study will examine the acute effects of a moderate dose of cannabis (12.5% THC) combined with an intoxicating amount of alcohol (BAC=0.08) on driving simulator performance of young drivers. Following an eligibility screening and practice session, a total of 70 participants aged 19 to 29 years will each complete 4 experimental sessions. During each session, participants will drink alcohol or placebo alcohol and smoke an active or placebo cannabis cigarette. The effects of alcohol and cannabis on the performance of driving-related skills will be assessed using a high-fidelity driving simulator. Cognitive, psychomotor, and mood effects will also be assessed.

Conditions

• Psychomotor Impairment

Interventions

DRUG

delta 9 tetrahydrocannabinol

A single cannabis cigarette (potency 12.5% delta 9 tetrahydrocannabinol) will be given to participants to smoke over a 10 minute period, ad libitum. If the cannabis cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose.

DRUG

placebo delta 9 tetrahydrocannabinol

A single placebo cannabis cigarette (\<0.03% delta 9 tetrahydrocannabinol) will be given to participants to smoke over a 10 minute period, ad libitum. If the placebo cannabis cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose (as this is a double-blind study).

DRUG

Alcohol

A single oral administration of an alcoholic beverage mixed in a 1:3 ratio of alcohol to tonic water to obtain a target blood alcohol content of 0.08mg%.

DRUG

Placebo alcohol

A single oral administration of a beverage containing tonic water of the same volume as the alcoholic beverage.

Sponsors & Collaborators

• Canadian Institutes of Health Research (CIHR)

  collaborator OTHER_GOV

• Health Canada

  collaborator OTHER_GOV

• Centre for Addiction and Mental Health

  lead OTHER

Principal Investigators

• Christine M Wickens, PhD · Centre for Addiction and Mental Health

Study Design

Allocation

RANDOMIZED

Purpose

OTHER

Masking

DOUBLE

Model

CROSSOVER

Eligibility

Min Age

19 Years

Max Age

29 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2017-07-04

Primary Completion

2020-01-17

Completion

2020-01-17

Countries

• Canada

Study Locations