Effects of Inhaled Cannabis on Driving Performance

Individuals will be recruited who are currently users of cannabis and alcohol to participate in this study. They will undergo a physical exam at screening. There will be six study visits where the subject will arrive at the Clinical Research Unit(University of Iowa Hospitals & Clinics) the night before dosing. At each visit subjects will be receive one of the following six dosing regimens: placebo alcohol with placebo cannabis; placebo alcohol with low-dose cannabis, placebo alcohol with higher-dose of cannabis, low dose alcohol with placebo cannabis; low dose alcohol with low dose cannabis, low dose alcohol with higher-dose of cannabis. After dosing, participants will have provide saliva samples and blood drawn periodically to check cannabis levels and will complete a driving simulation. After completing the drive, additional saliva samples and blood draws will occur and participants will be monitored until it is safe to transport home.

Inclusion criteria

• Healthy adult (age 21-55) men and women, based on medical and psychological evaluation
• Currently valid unrestricted (except for vision correction) US driver's license
• Licensed driver for at least the past two years
• Drove at least 1300 miles in the past year, by self-report
• Live within an 80 mile radius of NADS
• Available for an overnight stay followed by a full-day study session for six sessions
• Must be considered a light or moderate drinker according to Quantity-Frequency-Variability Scale (QFV)
• Cannabis use with a minimum frequency averaging at least one day per quarter and no more than three days a week during the three months prior to study entry
• Peripheral veins suitable for repeated venipuncture and/or placement of an intravenous catheter
• Systolic blood pressure within a clinically normal range (120 ± 30 mmHg) and -diastolic blood pressure of 80 ± 20 mmHg..
• Good command of written and spoken English
• Female subjects with reproductive potential must agree to use (and/or have their partner use) one (1) acceptable method of birth control beginning at the screening visit throughout the study (including intervals between treatment periods/panels) and until 2 weeks after the last dose of study drug in the last treatment period. Acceptable methods of birth control include the following: intrauterine device (IUD-with or without local hormone release), diaphragm, spermicides, cervical cap, contraceptive sponge, oral contraceptives or condoms. Abstinence is an alternative lifestyle and subjects practicing abstinence may be included in the study.

Exclusion criteria

• Presence of any clinically significant illness, as detected by history, physical examination, and/or laboratory tests, that might influence driving performance (e.g., seizures, sleep apnea, narcolepsy, vertigo, chronic fatigue syndrome) or put the subject at increased risk of adverse events (e.g., cardiac arrhythmia, hypertension)
• History of a clinically significant adverse event associated with cannabis or alcohol intoxication
• Donation of more than 450 mL of blood within 14 days of study drug administration
• If female, pregnant or nursing
• Currently interested in or participating in drug abuse treatment, or participated in drug abuse treatment within 60 days preceding study enrollment
• Currently taking drugs that are contraindicated for use with study drugs
• Requires any special equipment to aid in driving (ex. pedal extensions, hand brake or throttle, spinner wheel knobs or other non-standard equipment)
• Significant history of motion sickness or demonstrates significant simulator sickness during practice drives at screening (SSQ). Subjects must have scores below the following values on the SSQ: Nausea < 21, Oculomotor <32, Disorientation < 15, and Total Score < 32.
• Current alcohol or cannabis use disorder, as identified by the Alcohol Use Disorders Identification Test for alcohol or Cannabis Use Disorders Identification Test for cannabis.
• History of any illness that, in the opinion of the study investigator, might confound the results of the study or pose an additional risk to the subject from study participation
• Prior participation in a driver impairment or distraction-related research study conducted at NADS that uses the same base drive.