Cannabis Impairment Detection Application (CIDA)


Advanced Brain Monitoring




Driving Under the Influence
Alcohol Intoxication
Marijuana Intoxication


Drug: Alcohol (oral)
Drug: Cannabis (Very High% THC) (Inhaled)
Drug: Cannabis (THC) (Inhaled) Placebo
Drug: Cannabis (High% THC) (Inhaled)

Study type


Funder types




Details and patient eligibility


Subjects will participate in a 4-visit study protocol in which they will be asked to complete a set of computerized tasks and a 45-minute simulated drive in a driving simulator. Subjects will be administered marijuana of varying pre-determined concentrations of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) during 3 of the visits and alcohol during one of the visits. Throughout the duration of each visit, brain activity will be measured noninvasively using an electroencephalogram (EEG) headset. The purpose of this study is to: Further understand the effects of acute cannabis intoxication on driving performance in a driving simulator Develop and refine brain-based biomarkers of impairment due to acute cannabis intoxication

Full description

At the University of Iowa, subjects who currently use cannabis recreationally (> once a month but < 5 times a week) will be recruited. They will then undergo a screening visit in which consent is obtained, questionnaires are given, and a physical exam is administered. They will then be scheduled for their next 3 (or 4 if participating in the alcohol arm), which will be at least one week apart. At each visit, in counter-balanced manner, subjects will be administered 500 mg of either placebo Marijuana (trace amounts of THC), high THC marijuana (7.5%), or very high THC marijuana (12.5%). All marijuana will be inhaled ad libitum via a Volcano® Digit vaporizer. Additionally, a subset of subjects will be asked to complete a fourth study visit that administers alcohol in place of cannabis. As subjects complete the third study visit and meet criteria for the alcohol arm, they will be invited to participate in the fourth study visit until eighteen subjects complete the study's alcohol arm. After drug administration, subjects will be asked to complete a set of computerized neurocognitive tasks (1 hour), followed by a simulated drive (45 minutes). Throughout the duration of each visit, EEG will be collected. EEG is a non-invasive method of recording the electrical activity of the brain. Additionally, blood draws will be taken at pre-determined time points. Finally, subjects will be monitored until the drug effects have subsided sufficiently to ensure it is safe to transport them home. Subjects will be transported home.


124 patients




18 to 50 years old


Accepts Healthy Volunteers

Inclusion criteria

  • Men and women 18 to 50 years of age in good health (21 to 50 for alcohol arm)
  • Valid US driver's license and have been licensed driver for two years
  • Restrictions on driver's license limited to vision correction only
  • Drive at least three times per week
  • Must be able to drive without special or non-standard equipment
  • Must be able to attend three morning daytime study visits lasting approximately 5 to 6 hours
  • Must be willing to abstain from alcohol use in the day prior to their study appointments
  • Must be willing to abstain from use of their own cannabis while enrolled in the study
  • Live within 1-hour driving radius of National Advanced Driving Simulator (NADS)
  • Must currently use cannabis at least once every three months and no more than four times per week (must be current user)
  • Peripheral veins suitable for venipuncture
  • Blood pressure within clinically normal range
  • If invited to complete alcohol arm: Must be considered a light or moderate drinker according to Quantity-Frequency-Variability Scale (QFV) or, if a heavy drinker, not drink more than 1-2 times a week and not have a modal quantity of 5-6 drinks

Exclusion criteria

  • Females who are pregnant or test positive for pregnancy or are breastfeeding
  • Any known sleep disorders, or family history of sleep disorders
  • Any neurological or pulmonary disorders (or taking medications for such)
  • Any psychiatric disorder (or taking medications for such)
  • Any eating disorders
  • Recent (past 5 years) head injury, or older head injury with current symptoms
  • High blood pressure, Heart disease, diabetes, or history of stroke or taking medications to treat
  • Any known behavioral or attention disorder (or taking medications for such)
  • Untreated/Untreatable vision or auditory issues (because testing currently requires both senses)
  • Excessive tobacco use (more than 10 cigarettes a day)
  • Excessive caffeine use (5 or more servings per day)
  • Excessive alcohol (20 or more drinks per week)
  • Donation of 450 mL or more of blood in the two weeks preceding study drug administration
  • Regular use of pain medications other than over-the-counter
  • Any medication use that causes drowsiness or is contraindicated for driving
  • Use of prescription drugs not prescribed to them or illicit drugs other than cannabis
  • Propensity to motion sickness (more than 2-3 episodes where intensity is moderate or above)
  • History of substance abuse or substance addiction
  • Currently participating in or interested in drug abuse treatment, or participation in a program in past 60 days
  • Current cannabis use disorder or alcohol use disorder [as determined by scores on the Cannabis Use Disorder Identification Test (CUDIT) and Alcohol Use Disorder Identification Test (AUDIT)]

Trial design

124 participants in 4 patient groups, including a placebo group

0% THC/ 0% CBD
Placebo Comparator group
Drug: Cannabis (THC) (Inhaled) Placebo
THC (5-10% [37.5 mg]) / Low CBD (<1% [2.5 mg])
Experimental group
Drug: Cannabis (High% THC) (Inhaled)
THC (>10% [62.5 mg]) / Low CBD (<1% [2.5 mg])
Experimental group
Drug: Cannabis (Very High% THC) (Inhaled)
0.065% BAC
Experimental group
Drug: Alcohol (oral)

Trial contacts and locations



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