Effects of THC on Alcohol Consumption and Brain Function
This study wants to learn why some people use alcohol and cannabis (THC) at the same time, and how these drugs affect the brain. We are looking at how THC changes brain activity and how much alcohol people drink.
Why this Research Matters
Alcohol and cannabis are often used at the same time, and their effects can overlap. Cannabis edibles, which can have high amounts of THC, haven’t been studied much in labs. We don’t know how these products might change how people drink alcohol. In this study, we will give THC by mouth and see how it affects the brain. We will also give alcohol to drink during the study.
What to Expect
If you join the study, there will be three study visits. The first visit lasts about 90 minutes and includes questions about mood, mental health, and substance use. After the final visit, a short daily survey will be sent to your phone for two weeks, asking about alcohol and cannabis use. Each survey takes less than three minutes to complete. Visits 2 and 3 take place at the Anschutz Campus, with transportation provided. Upon arrival, alcohol and drug tests will be done, and a light breakfast and lunch will be provided. A capsule containing either THC or a placebo will be given, and blood samples will be collected. A brain scan will follow, using pictures and tasks to measure brain activity. Afterward, an alcoholic drink will be served, followed by questions about how it feels. Later, there’s a chance to drink more or keep the money instead. After drinking, time will be spent in the lab until alcohol levels are low enough to leave safely, usually by 9–10 pm. Dinner will be provided, along with time to relax, use personal devices, and read information about alcohol. A ride home will be arranged with a friend or paid ride service.
Study Duration
There will be three study sessions, with about one week between each one. After the final session, short surveys will be sent to your phone once a day for two weeks. The entire study will take around four weeks to finish.
Who can Participate
You may be able to join if:
- You are between 21 and 40 years old
- You had at least:
- 5 drinks in one day (if male), or
- 4 drinks in one day (if female) in the past year
- You used a high dose of cannabis (20mg or more of THC) at least once in the past year
- You used alcohol and cannabis at the same time within the past month
- You are currently getting treatment for alcohol or cannabis use
- You are pregnant, trying to get pregnant, or breastfeeding
- You have metal in your body that makes MRI scans unsafe
- You weigh more than 400 pounds
- You have liver disease
Study ID
Protocol Number: 22-1314
Compensation Information
Meet the Team
Principal Investigator