Combined and Separate Effects of Cannabis and Tobacco: Psychomotor, Subjective and Physiological Outcomes

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)