Combined Alcohol and Cannabis Effects on Skills of Young Drivers
Condition: Psychomotor Impairment
MeSH terms: Psychomotor Disorders
Study type: Interventional
Phase: Early Phase 1

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.
    

Detailed description: 
      The proposed study will pursue the following primary aims:

      Aim 1: 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 29. BAC and biological fluids will be
      measured up to 5 hours following drug exposure.

      Aim 2: Explore the effects of driving history, driving attitudes, and individual difference
      measures (e.g., demographics, drug and alcohol use, etc.) on the acute effects of alcohol and
      cannabis on driving simulator performance of young drivers. Exploratory analyses will be
      undertaken to determine if the acute 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. Although a placebo condition is part of the study, this is not
      a treatment study.

      Initial contact with potential participants will be made via telephone, and study personnel
      will conduct a telephone screen for eligibility. Upon eligibility confirmation by telephone,
      participants will be asked to attend CAMH for an eligibility assessment. Participants will
      attend CAMH for a total of 6 study sessions (an eligibility assessment, a practice day, and 4
      test sessions).

      At each of four test sessions, participants will undergo one of these alcohol and cannabis
      exposure conditions: 1) placebo alcohol and placebo cannabis; 2) intoxicating dose of alcohol
      and placebo cannabis; 3) placebo alcohol and active cannabis, and; 4) intoxicating dose of
      alcohol and active cannabis. The order of these conditions will be randomly assigned.
      Participants will complete the alcohol manipulation followed by the cannabis manipulation.
      The alcohol and cannabis exposure sessions will be separated by at least 72 hours.

      Participants will be asked not to use cannabis for 72 hours and alcohol for 48 hours prior to
      attending CAMH.

      In certain instances, the Qualified Investigator may ask a participant to return for
      re-screening, e.g. repeat of urine test or other assessments performed for eligibility
      assessment. Also, in case of unforeseen delays in scheduling study participation, the
      Qualified Investigator will determine if there is a need to ask a participant to repeat some
      assessments, e.g., physical examination.
    

Intervention name(s): delta 9 tetrahydrocannabinol; placebo delta 9 tetrahydrocannabinol; Alcohol; Placebo alcohol
Intervention type(s): Drug; Drug; Drug; Drug
Intervention description(s): 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.; 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).; 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%.; A single oral administration of a beverage containing tonic water of the same volume as the alcoholic beverage.
Other intervention name(s): cannabis sativa; marijuana; cannabis sativa; marijuana; ethanol; Tonic water
Intervention MeSH terms: Ethanol; Dronabinol
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Other