Age Differences in the Effects of Cannabis on Simulated Driving

Study Overview
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Brief Summary
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Epidemiological studies suggest that the use of cannabis is associated with an increase in the risk of motor vehicle collisions. It is also known that younger users may be at increased risk for motor vehicle collisions. Further, the frequency with which cannabis is used may be an important variable in determining the effects of cannabis on driving. The purpose of the present study will be to investigate the effects of cannabis on simulated driving in young as compared to middle-aged drivers. Half of the participants will be occasional users of cannabis and half will be frequent users of cannabis.

Detailed Description
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Epidemiological studies have established that the use of cannabis can increase the risk of a motor vehicle collision. A number of variables can influence the effects of cannabis on driving. For example, frequent users of cannabis have been shown to have different cognitive and physiological responses to cannabis as compared to occasional users. In addition, we know that younger drivers are more likely to be involved in motor vehicle collisions after alcohol use as compared to older users. The contribution of age and experience with cannabis on cannabis-mediated effects on driving have yet to be delineated in laboratory studies. The purpose of the present investigation will be to determine whether cannabis has different effects on driving in young, as compared to middle aged, drivers. Half of each age group will be occasional users of cannabis and the other half will be frequent users. Eligible participants will attend the laboratory for two test sessions; in one session they will smoke a cannabis cigarette and in the other they smoke a placebo cigarette. Participants will drive a driving simulator before and after smoking the cigarette. Blood for measurement of THC and metabolites will also be collected before smoking the cigarette and at a number of times after smoking. Subjective and cognitive tasks will be completed before and after smoking. It is hoped that the findings of this study will help to inform public perception and policy into the potential effects of cannabis on driving.

Official Title
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The Influence of Age on Driving-related Cannabis Effects: Exploring Cannabis Use Frequency and Related Factors

Conditions
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Cannabis

Intervention / Treatment
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* Drug: Cannabis
* Drug: Placebos


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 19-25 or 35-45 years of age; Use of smoked cannabis for recreational purposes on up to 2 occasions per week or 5+ occasions per week but on no more than 5 days per week; Holds a class G or G2 Ontario driver's licence (or equivalent from another jurisdiction) for at least 12 months; Willing to abstain from using alcohol for 48 hours and cannabis for 72 hours prior to Practice and Test Sessions; Willing to abstain from all other drugs not prescribed for medical purposes for the duration of the study; Resides within the Metropolitan Toronto area (in which the trial site is located) or can reside with friends/family in the Metropolitan area after a Test Session; this area may be extended to the Greater Toronto area if recruitment challenges arise; Provides written and informed consent. Exclusion Criteria: Urine toxicology screens negative for cannabis upon Eligibility Assessment; Use of cannabis primarily for therapeutic purposes; Diagnosis of medical condition that contraindicates use of cannabis determined by self-report as judged by the Qualified Investigator; this includes a history of hypersensitivity to cannabinoids smoke, respiratory disease and/or severe cardiovascular, cerebrovascular, renal or liver disease. Smoking cannabis is not recommended for patients with respiratory diseases, and they will be excluded Diagnosis of psychiatric condition that contraindicates use of cannabis determined by self-report and SCID; Females: Pregnancy or breastfeeding; Meets criteria for current or lifetime alcohol or other substance use disorder (DSM-5), except tobacco use disorder and caffeine use disorder Is a regular user of medications that affect brain function (based on self-report); this includes concomitant therapy with sedative-hypnotics or other psychoactive drugs Use of anti-hypertensives First-degree relative diagnosed with schizophrenia or another psychotic disorder.

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo cannabis<br>Participants will drive the simulator before and after smoking a placebo cannabis cigarette (<1% THC) | Drug: Placebos<br>* 750mg cigarette of plant material<br>* Other names: Dummy;|
| Experimental: Active cannabis<br>Participants will drive the simulator before and after smoking an active cannabis cigarette (12.5% THC) | Drug: Cannabis<br>* 750mg cigarette of plant material<br>* Other names: Marijuana;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Standard deviation of lateral position | A measure of 'weaving' when driving the simulator (meters) | Before cannabis exposure and 30 minutes and 2 hours after cannabis exposure | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean speed | A measure of the average speed while driving the simulator (km/hr) | Before cannabis exposure and 30 minutes and 2 hours after cannabis exposure | 
| Standard deviation of speed | A measure of the variability in speed while driving the simulator (km/hr) | Before cannabis exposure and 30 minutes and 2 hours after cannabis exposure | 
| Maximum speed | A measure of the greatest speed obtained while driving the simulator (in km/hr) | Before cannabis exposure and 30 minutes and 2 hours after cannabis exposure | 
| Minimum time to collision | A measure of time it would take to impact the car in front if that car slowed down (seconds) | Before cannabis exposure and 30 minutes and 2 hours after cannabis exposure | 
| Following distance | A measure of the distance between the car being driven and the car in front (meters) | Before cannabis exposure and 30 minutes and 2 hours after cannabis exposure | 
| Braking latency | A measure of the time it takes to move the foot from the gas pedal to the brake when a stop sign is encountered (seconds) | Before cannabis exposure and 30 minutes and 2 hours after cannabis exposure | 
| Number of collisions | The number of collisions while driving the simulator (total number) | Before cannabis exposure and 30 minutes and 2 hours after cannabis exposure | 
| Blood concentration of delta-9-tetrahydrocannabinol (THC) | A measure of the psychoactive component of cannabis in blood (ng/ml) | Before cannabis exposure and 5, 15, 30 minutes and 1, 2, and 3 hours after cannabis | 
| Blood concentration of carboxy-tetrahydrocannabinol (THC-COOH) | A measure of the inactive metabolite of cannabis in blood (ng/ml) | Before cannabis exposure and 5, 15, 30 minutes and 1, 2, and 3 hours after cannabis | 
| Blood concentration of 11-hydroxy-tetrahydrocannabinol (11-OH-THC) | A measure of the active metabolite of cannabis in blood (ng/ml) | Before cannabis exposure and 5, 15, 30 minutes and 1, 2, and 3 hours after cannabis | 
| Systolic blood pressure | A vital sign (mmHg) | Before cannabis exposure and 5, 15, 30 minutes and 1, 2, 3, 4 and 5 hours after cannabis | 
| Diastolic blood pressure | A vital sign (mmHg) | Before cannabis exposure and 5, 15, 30 minutes and 1, 2, 3, 4 and 5 hours after cannabis | 
| Heart rate | A vital sign (beats/minute) | Before cannabis exposure and 5, 15, 30 minutes and 1, 2, 3, 4 and 5 hours after cannabis | 
| Temperature | A vital sign (Celsius) | Before cannabis exposure and 5, 15, 30 minutes and 1, 2, 3, 4 and 5 hours after cannabis | 
| Respiration rate | A vital sign (respirations/minute) | Before cannabis exposure and 5, 15, 30 minutes and 1, 2, 3, 4 and 5 hours after cannabis | 
| Visual Analog Scales such as 'I feel this effect', 'I like this drug effect', 'I feel the good effects' | A measure of the subjective effects of cannabis (on a scale of 0 to 100, where is 100 is the strongest level of agreement) | Before cannabis exposure and 5, 15, 30 minutes and 1, 2, 3, 4 and 5 hours after cannabis | 
| Digit Symbol Substitution Test | A measure of the cognitive effects of cannabis (reaction time in seconds) | Before cannabis exposure and 70 minutes after cannabis | 
| Verbal Free Recall Task | A measure of the cognitive effects of cannabis (number correct) | Before cannabis exposure and 70 minutes after cannabis | 
| Useful Field of View Test | A measure of the cognitive effects of cannabis (speed of visual processing, in milliseconds) | Before cannabis exposure and 70 minutes after cannabis | 
| Grooved Pegboard Test | A measure of the cognitive effects of cannabis (performance speed in milliseconds) | Before cannabis exposure and 70 minutes after cannabis | 
| Simple and Choice Reaction Time Tasks | A measure of the cognitive effects of cannabis (milliseconds) | Before cannabis exposure and 70 minutes after cannabis | 
| Vienna Risk-Taking Test | A measure of the amount of risk-taking (latency) | One hour after cannabis exposure |