Joint effects: new study tests cannabis and tobacco on the road

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * • Adults aged 19 years to 45 years (to control for the effects of age on cognition) * Smoke or vape cannabis at least once a month but no more than 4 times a week (to avoid enrolling people with cannabis use disorder who may experience withdrawal when asked to abstain from cannabis) * Experience with smoked cannabis in the past year * Report use of at least 100 cigarettes in their lifetime to ensure familiarity with the tobacco used in the present study * Use of any nicotine (smoked, vaped, etc) in the past year * G2 or full G driver's licence for at least a year * Willing to abstain from alcohol and other drugs (other than drugs required for treatment of a medical condition) for 48 hours prior to study session * Normal heart rate and blood pressure as determined by the QI (because cannabis and tobacco increase heart rate) * Normal ECG (because cannabis and tobacco increase heart rate) * Willing to abstain from cannabis for 72 hours prior to the test session and from smoking tobacco for 12 hours * Willing to use an accepted form of contraception during the study (both males and females) * Past lifetime experience with co-use of cannabis or tobacco (either simultaneous or concurrent) * Provides written and informed consent Exclusion Criteria: * • Use of psychoactive medications or drugs * Current alcohol or other substance use disorder, including cannabis (as assessed with the SCID) * Current or past nicotine dependence (to avoid precipitating a relapse) * Withdrawal symptoms as assessed with the Marijuana Withdrawal Checklist \[57, 58\] * A score of less than 10 on the Clinical Institute Withdrawal Assessment for Alcohol (CIWA-Ar) \[59\] * Family history of schizophrenia or psychosis (to avoid giving cannabis to anyone with a predisposition to psychosis) * Respiratory illnesses (due to the smoked route of administration in this study) * Any serious medical condition precluding participation as judged by the responsible study physician * Pregnancy or breastfeeding * Negative urine screen for cannabis at eligibility assessment (to ensure experience with cannabis) * Neurological disorders that may affect cognitive function * Treatment-seeking for tobacco or cannabis use * Use of more than 5 cigarettes a day (to avoid confound of the effects of chronic smoking on measures) * Concomitant therapy with sedative-hypnotics or other psychoactive drugs (counter-indicated with cannabis)