Clinical Trial: Combined Alcohol and Cannabis Effects on Skills of Young Drivers

Study Status: Not yet recruiting
Recruit Status: Not yet recruiting
Study Type: Interventional

Official Title: Effects of Combined Alcohol and Cannabis on Young Drivers' Simulated Driving

Brief 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 residual or 'hangover' effects of these substances on road safety are also not well understood, but may be substantial. To date, the residual effects of combined use have not been examined. The current study will examine the acute and residual 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 25 years will each complete 8 experimental sessions (2 sessions/week). During the first session of each week, subjects 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. Twenty-four hours after alcohol/drug exposure, subjects will attend the second session of the week where driving-related, cognitive, psychomoto

Detailed Summary:

The proposed study will pursue the following primary aims:

Aim 1: Examine the residual 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. Simulated driving performance, tests of cognition, verbal memory, and mood will be measured concurrently with levels of cannabinoids and alcohol metabolites in biological fluids at approximately 24 hours following acute drug exposure in male and female drivers aged 19 to 25.

Aim 2: 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. Simulated driving performance, tests of cognition, verbal memory, and mood will be measured concurrently with BAC and levels of cannabinoids in biological fluids before and after acute drug exposure in male and female drivers aged 19 to 25. BAC and biological fluids will be measured up to 5 hours following drug exposure.

Aim 3: Explore the effects of driving history, driving attitudes, and individual difference measures (e.g., demographics, drug and alcohol use, etc.) on the acute and residual effects of alcohol and cannabis on driving simulator performance of young drivers. Exploratory analyses will be undertaken to determine if the acute and residual effects of cannabis plus alcohol on the driving simulator task are influenced by these measures.

Study Design and Duration

This study will be a within-subjects, double-blind, double-dummy, placebo-controlled, counterbalanced, randomized clinical trial assessing the impact of alcohol and cannabis combined on driver behaviour. Althou
Sponsor: Centre for Addiction and Mental Health

Current Primary Outcome: Psychomotor impairment [ Time Frame: Alcohol exposure is Time 0. Cannabis exposure follows 15 minutes after Time 0. Driving simulation tests occur 30 minutes before, 30 minutes after, and 24 hours after Time 0. ]

The driving simulator will objectively measure changes in driving behavior after alcohol and/or cannabis exposure.


Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Subjective drug effects [ Time Frame: Alcohol exposure is Time 0. Cannabis exposure follows 15 minutes after Time 0. Visual analogue scales are administered 2 hours before as well as 15, 30, 45, and 75 minutes and 2, 3, 4, 5, and 24 hours after Time 0. ]
    Visual analogue scale measures how participants feel before and after alcohol and/or cannabis exposure.
  • Neuro-cognitive testing [ Time Frame: Alcohol exposure is Time 0. Cannabis exposure follows 15 minutes after Time 0. Neuro-cognitive testing is administered 2 hours before Time 0 as well as 75 minutes and 24 hours after Time 0. ]
    Measures changes in performance related to attention, memory, field of view, and dexterity before and after alcohol and/or cannabis exposure.
  • Breath alcohol content [ Time Frame: Alcohol exposure is Time 0. Cannabis exposure follows 15 minutes after Time 0. Breath alcohol content is measured 2 hours before Time 0 as well as 15, 30, 45, and 75 minutes and 2, 3, 4, 5, and 24 hours after Time 0. ]
    Changes in BAC after drinking alcohol.
  • Blood concentration for delta 9 tetrahydrocannabinol, carboxy-tetrahydrocannabinol, and 11 hydroxy tetrahydrocannabinol. [ Time Frame: Alcohol exposure is Time 0. Cannabis exposure follows 15 minutes after Time 0. Blood concentration for THC, THC-COOH, and 11-OH-THC is assessed 2 hours before Time 0 as well 30 minutes and 24 hours after Time 0. ]
    Changes in concentration of delta 9 tetrahydrocannabinol (THC) , carboxy-tetrahydrocannabinol (THC-COOH), and 11 hydroxy tetrahydrocannabinol (11-OH-THC) in blood.
  • Urine cannabinoids corrected for creatinine [ Time Frame: Alcohol exposure is Time 0. Cannabis exposure follows 15 minutes after Time 0. Ratio of excreted THC metabolite carboxy-THC to creatinine is assessed 2 hours before Time 0 as well as 5 and 24 hours after Time 0. ]
    Determination of the ratio of excreted THC metabolite carboxy-THC to creatinine will determine whether participants have used cannabis between testing days, and hence will be excluded from further participation.
  • Blood concentration for ethylglucuronide and ethylsulphate [ Time Frame: Alcohol exposure is Time 0. Cannabis exposure follows 15 minutes after Time 0. Blood concentration for ethylglucuronide and ethylsulphate is assessed 2 hours before Time 0 and 24 hours after Time 0. ]
    Concentration of alcohol metabolites ethylglucuronide and ethylsulphate in blood will determine if participants have used alcohol between testing days, and hence will have their data excluded from the final analysis.


Original Secondary Outcome: Same as current

Information By: Centre for Addiction and Mental Health

Dates:
Date Received: April 4, 2017
Date Started: April 2017
Date Completion: January 2020
Last Updated: April 10, 2017
Last Verified: April 2017