Abuse Cannabis, Cognitive Impairment, Driving Impaired
Conditions
Brief summary
Epidemiological studies have established a link between collisions while driving and cannabis use. With the changing legal landscape around cannabis, there is much interest in determining per se limits of cannabis while driving. The present study will evaluate driving on a driving simulator after smoking placebo or cannabis with 3 different levels of THC. THC is the active component in cannabis and blood, urine and oral fluid levels of THC will be correlated with driving impairment.
Detailed description
Participants will attend the laboratory for 4 separate sessions, separated by about a week. In each session, participants will receive one of 3 doses of smoked cannabis or a placebo. Participants will not know which dose they are receiving. Participants will complete questionnaires, do cognitive tests and drive on a driving simulator before and after smoking the cannabis or placebo cigarette. Blood, urine and oral fluid will be collected throughout the 7-8 hour session to determine levels of THC and its metabolites. These values will be correlated with measures of driving impairment.
Interventions
DRUGCannabis
Participants will smoke as much of the cigarette as they wish
DRUGPlacebo
Participants will smoke a placebo cigarette
Sponsors
Centre for Addiction and Mental Health
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Intervention model description
This will be a within-subjects, counterbalanced, placebo-controlled study of placebo or 3 doses of cannabis
Eligibility
Sex/Gender
ALL
Age
19 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* Near daily use of cannabis (1-5 days/week) confirmed by self-report and urine screening * Has held a class G2 or G licence (or equivalent from another jurisdiction) for at least 12 months * Willing to abstain from using cannabis for 72 hours prior to each practice or test session * Willing to abstain from alcohol for 48 hours prior to each session, and to abstain from all other drugs not medically required for the duration of the study (beginning 48 hours prior to the practice session) * Provides written and informed consent
Exclusion criteria
* Diagnosis of severe medical or psychiatric condition * Meets criteria for current or lifetime alcohol or other substance use disorder, except tobacco use disorder and caffeine use disorder * Regular user of medication that may affect cognitive functioning and/or driver performance * Family history of schizophrenia or other psychotic disorder * Pregnant, looking to become pregnant, or breastfeeding
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Mean speed | Change in speed of driving between the time before smoking the cigarette and either 30 or 90 minutes after smoking the cigarette | Speed of driving the simulator |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| reaction time | Change in measure from before smoking the cigarette to either 30 or 90 minutes after smoking | Driving measures |
| Blood concentrations of THC and metabolites | Change from before smoking cigarette to various time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | Blood will be taken to determine how much THC entered the blood |
| Oral fluid concentrations of THC and metabolites | Change from levels before smoking to 4 time points after smoking: 30 minutes, 90 minutes, 2 hours and 6 hours | Participants will provide oral fluid to determine how much THC is in the oral fluid |
| Systolic and Diastolic Blood pressure | Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | Vital signs |
| Heart rate | Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | Vital signs |
| Standard deviation of lateral position | Change in measure from before smoking the cigarette to either 30 or 90 minutes after smoking | Driving measures |
| Temperature | Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | Vital signs |
| Visual Analog Scales | Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | Tests designed to assess the degree of subjective effects of the drug. The questions will be scored on a scale from 0 to 100 and will consist of: 'I like this drug effect', 'this feels like cannabis', 'I feel this effect', 'I feel this high', 'I feel the good effects', 'I feel the bad effects', 'I feel the rush' |
| Verbal free recall test | Change from pre-smoking levels to those observed 60 minutes after smoking | Test of memory: Participants will be asked to recall words that are read from a list |
| Useful field of view | Change from pre-smoking levels to those observed 60 minutes after smoking | A computer test for visual processing speed, selective and divided attention |
| Respirations | Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | Vital signs |
Countries
Canada
Outcome results
None listed