University Health Service

pensive man, plaid shirt, photo by Priscilla Du Preez via Unsplash

Health alerts:


Key info for U-M students to know (see more below):

  • It's illegal to:
    • Possess or use cannabis if under age 21
    • Possess or use at any age on U-M property
    • Use in public
  • Research shows that cannabis use, and withdrawal from cannabis, can increase anxiety and sleep problems.
  • If you're concerned about cannabis use, consider Wellness Coaching for Alcohol and Other Drugs a free, non-judgmental opportunity for U-M students to consider their use. 
  • Cannabis use, vaping and cigarette smoking can compromise the respiratory system and impair immune function.
  • Concerned about the impact of use during the COVID-19 pandemic? U-M Tobacco Consultation Service offers free cessation counseling for U-M students, faculty, staff and the Ann Arbor community. Call 734-998-6222 or email quitsmoking@med.umich.edu for an appointment.

Cannabis is a rapidly evolving topic because:

  • Cultivation of the plant is producing more potent and more specialized strains.
  • More products, and more ways to use products, are available now.
  • Some states, including Michigan, have legalized the use of cannabis for medical and/or limited recreational purpose.
  • New research is better identifying the effects of cannabis. This is due in large part to data collected from states that have legalized limited recreational use and because a ban on medical research has been lifted.

University Health Service helps students navigate this evolving issue and offers the following information and resources.


What students need to know about cannabis in order to make informed decisions and reduce harm:

How common is cannabis use on campus? According to the 2018 U-M National College Health Assessment, 81% of U-M students had NOT used cannabis in the past 30 days. That's more than 35,000 students.

Is it possible to have a bad reaction to cannabis?
Yes. Signs of a bad reaction may include extreme confusion, anxiety, paranoia, panic, fast heart rate, delusions or hallucinations, increased blood pressure, and severe nausea or vomiting. (Note that the Medical Amnesty law protects people who call for help, if they invoke it at the time they call.) 

The effects of cannabis can be unpredictable because:

How does cannabis affect the brain?
According to the CDC, cannabis use directly affects the brain, specifically the parts of the brain responsible for memory, learning, attention, decision making, coordination, emotions, and reaction time.

  • Heavy users of cannabis can have short-term problems with attention, memory, and learning, which can affect relationships and mood.
  • Cannabis also affects brain development. When marijuana users begin using as teenagers, the drug may reduce attention, memory, and learning functions and affect how the brain builds connections between the areas necessary for these functions. Marijuana’s effects on these abilities may last a long time or even be permanent. 
  • Developing brains, like those in babies, children, and teenagers are especially susceptible to the harmful effects of cannabis. 

How does cannabis affect mental health?
According to the CDC,

  • Cannabis use, especially frequent (daily or near daily) use and use in high doses, can cause disorientation, and sometimes cause unpleasant thoughts or feelings of anxiety and paranoia. 
  • Cannabis users are significantly more likely than non-users to develop temporary psychosis (not knowing what is real, hallucinations and paranoia), and individuals with frequent use during adolescence may be more likely to develop chronic psychosis (most likely those individuals with a genetic vulnerability).
  • Cannabis use has also been linked to depression and anxiety, and suicide among teens. However, it is not known whether this is a causal relationship or simply an association.

How does cannabis affect the lungs?
According to the CDC,

  • Health alert: The Centers for Disease Control and Prevention recommends that you should not use e-cigarette or vaping products that contain THC due to risk of serious lung injury.
  • Smoked cannabis, in any form, can harm lung tissues and cause scarring and damage to small blood vessels. Smoke from cannabis contains many of the same toxins, irritants, and carcinogens as tobacco smoke. Smoking cannabis can also lead to a greater risk of bronchitis, cough, and phlegm production. 

How does cannabis affect a baby during pregnancy and breastfeeding?
According to the CDC,

  • Cannabis use by mothers during pregnancy may be linked to problems with attention, memory, problem-solving skills, and behavior problems in their children. 
  • Using cannabis while breastfeeding can allow harmful chemicals to pass from the mother to the infant through breast milk or secondhand smoke exposure. 

How does cannabis affect drivers?
According to the CDC (PDF), cannabis can slow drivers' reaction time and ability to make decisions, impair coordination, distort perception, and lead to memory loss and difficulty in problem-solving.

Is it possible to become addicted to cannabis? 
Yes, according to the CDC, about 1 in 10 cannabis users will become addicted, called cannabis use disorder.  For people who begin using before age 18, that number rises to 1 in 6.


What students need to know about cannabis-related laws in the state of Michigan:

  • The use of recreational or medicinal cannabis in any form, including edibles and extracts, is prohibited on university property by university policy and federal law. This is because federal law prohibiting cannabis preempts state laws that legalize the drug.
  • Possession of cannabis on U-M property is a misdemeanor with the possible consequences of fines, arrest, and jail time. For anyone under 21, possession of cannabis in the City of Ann Arbor is a civil infraction with a fine that increases with each additional infraction.
  • In the City of Ann Arbor, it is illegal for anyone to to use cannabis in public or drive under the influence of cannabis.
  • For more information about laws, please see Marijuana FAQs from the U-M Department of Public Safety and Security 

Resources to explore cannabis use and get early intervention or treatment, as needed:

  • Wellness Coaching for Alcohol and Other Drugs is a confidential, non-judgemental conversation offered free to all U-M students who want to explore their cannabis use.
  • e-TOKE (Marijuana e-CHECKUP TO GO) is an online, personalized, brief screening tool that lets you see how your cannabis use, family risk and campus norms affect your life and future. 
  • Helping a Friend suggests ways to talk with someone else about their use.
  • UHS Care Managers are available to talk about concerns related to cannabis use and can help connect to resources.
  • See more Resources for Alcohol and Other Drugs or you may call Wolverine Wellness at 734-763-1320 for help in navigating resources. 

Are you in recovery from use of cannabis, alcohol or other drugs? 

Consider joining the Collegiate Recovery Program, which provides holistic, tailored support to U-M students who are in recovery from alcohol or other drug problems.


More information:

The CDC offers several excellent resources about the health and well-being effects of cannabis:

The Legalization of Marijuana in Colorado: The Impact (PDF) documents changes from 2013 to 2019 in Colorado.