Marijuana Facts


While reviewing the information below, please remember that per the Student Code of Conduct:
“The use or possession of medical marijuana in the workplace and on campus is restricted by federal laws, such as the federal Safe and Drug Free Schools and Communities Act and the Drug-Free Workplace Act.   Accordingly, the University of Pittsburgh prohibits the use or possession of marijuana on campus.”


What is marijuana?

Marijuana (aka weed, pot, herb, etc.) is the dried flowers and leaves of the Cannabis sativa plant.   There are many ways it is used, including smoking, vaping and edibles.   How it is consumed will impact the onset and length of the high.   Marijuana that is smoked will produce a high that will typically peak within 30 minutes with the high last a couple of hours.   When consumed as an edible, it takes longer for your body to digest and metabolize it, resulting in a peak high taking up to a couple of hours, and the effects of the high lasting several hours.

There are more than 500 chemical compounds in marijuana, with more than 100 types of cannabinoids, but the main psychoactive chemical in marijuana is delta-9-tetrahydrocannabinol or THC.   The levels of THC in marijuana can vary widely depending on the strain or type of marijuana being used.   Higher levels of THC have been associated with increased risk of anxiety, paranoia and even hallucinogenic reactions.

How does marijuana impact the body?

The Brain -
Marijuana use causes changes in your brain’s chemistry, inhibiting the function of neurotransmitters that transfer information from one nerve cell to another.   This results in negative impacts on short-term memory, focus, judgement, and coordination.   Changes in mood are also sometimes reported.   Regular use of marijuana can negatively impact the ability to learn, focus and remember information as well as decrease motivation to accomplish tasks, even after the high is over (which increases the risks of things like poor academic performance).   Additionally, in high doses or with high potency marijuana, there are reports of hallucinations, delusions and even cases of psychosis that can occur.   Marijuana also disrupts sleep by interrupting the REM sleep cycle.

Current research suggests that exposure to marijuana during development can also impact how the brain develops, which may be associated with long term impacts.   According to the National Institute on Drug Abuse, some research suggests that regular use during adolescence may impact brain functions such as memory, learning and impulse control.

The Lungs-
When marijuana is smoked, it is similar to tobacco smoke in that there are volatile chemicals and tars produced with combustion.   This can decrease the effectiveness of the ability of the cilia to clean the lungs, which as a result can increase the risk of respiratory infections including bronchitis.   Marijuana smoke has been found to contain carcinogenic chemicals, so there is some increased risk of lung cancers, however more research is needed to determine what extent this risk presents.

Cardiovascular System-
Marijuana tends to cause a blood pressure to drop, which then causes the heart rate to speed up for up to 3 hours after smoking.   One’s heart rate may increase 20 to 50 beats more per minute, or in some cases it can even double!   Research suggests that there is a temporary increased risk of heart attack for some individuals during this time.   Blood vessels also enlarge, which is what causes the eyes to appear blood shot.   There is also an increased risk of fainting or falls due to orthostatic hypotension.

Although rare, in some circumstances chronic marijuana use has been associated with “Cannabinoid Hyperemesis Syndrome”.   The user experiences severe nausea and vomiting which can result in dehydration.   Additionally, sometimes individuals report “greening out”, which is where someone gets sick after smoking marijuana.   They may sweat, feel dizzy, experience nausea and even start vomiting.

How does marijuana impact mental health?

Many substances, including marijuana, can present risks to mental wellness.   There is a link between marijuana use and mental health concerns for some individuals.   The use of marijuana has been linked to issues such as depression and anxiety.   There are also reports of hallucinations, delusions and paranoia that are reported, especially with potent marijuana or with long - term use.   Those who use marijuana heavily are also more likely to report thoughts of suicide than those who do not use it.

More recently there have been studies that have linked marijuana use with the onset of schizophrenia.   This is not to say that marijuana causes schizophrenia, however there is an association between use, especially long term or chronic use or use during adolescence, and the development of schizophrenia.   More research is needed to fully understand the connection. Marijuana use can also worsen symptoms for other psychiatric disorders, like bipolar disorder.

Is marijuana addictive?

Yes, marijuana does present a risk for substance use disorders.   This can include addiction, which is the compulsive need to use it.   According to the CDC, about 1 in 10 people who use marijuana will become addicted to it, and for those who begin using it before the age of 18, the number rises to 1 in 6.

Marijuana use can also result in withdrawal symptoms that present in both physical and psychological manners.   Possible withdrawal symptoms include changes in appetite, mood changes, depression, irritability, anxiety, sleeping difficulties, headaches, trouble focusing, cravings and stomach problems.   The severity of symptoms will vary person to person.   When you regularly use marijuana, your body will become used to it, developing a tolerance, which is associated with withdrawal symptoms.

How do I recognize a problem with marijuana use?

Marijuana use can become problematic for some individuals.   Some possible warnings signs include:

  • Difficulty controlling your use or marijuana, including repeated, failed attempts to reduce or stop use, and/or using it in larger amounts or over a longer period than you intended
  • Tolerance, which is needing more of the substances to get the same feelings, or experiencing a reduced effect when using the same amount
  • Spending a great deal of time occupied with acquiring, using, or recovering from the effects
  • Cravings to use, which can include intrusive thoughts or images
  • Continuing to use it, despite negative impacts like criminal charges, impacts on relationships or impacts on productivity
  • Using despite negative impacts on relationships, work, academics or other responsibilities or obligations
  • Hazardous use, such as driving while high
  • Withdrawal symptoms when decreasing or stopping use
  • Missing class or failing to finish assignments due to marijuana use
  • Finding that it’s hard to be happy or get through your day without it

If you are concerned about your marijuana use, or possible impacts it is having on you, please contact the University Counseling Center for assistance:

What about using marijuana with other substances?

Generally speaking, mixing any substances can result in negative, and sometimes even dangerous, outcomes.   This applies to marijuana as well, though the types of risks and side effects can vary.   Mixing alcohol with marijuana, for example, can result in increased impairment, which may increase the risks associated with accidents or decision making.   There is an increased report of “greening out” when alcohol and marijuana are mixed, resulting in the user becoming ill.   Some research that indicates that marijuana could also impact how some prescription medications work in the body.

It is recommended to talk to your doctor or pharmacist to talk about possible interactions between marijuana and other substances or prescription medications.

Is marijuana illegal?

Marijuana is illegal according to federal law.   Recreational use is also illegal in the state of Pennsylvania.   The University follows all local, state, and federal laws so the possession, sale, and/or use of marijuana so it is against University policy, too.   Violation of laws and policies can result in legal troubles, such as fines, and/or can also result in disciplinary action from the University of Pittsburgh.   For more information on University policy, please see The Student Code of Conduct, which is found here:

Content resources: An American Addiction Centers Resource,

Center for Disease Control and Prevention,

The National Institute on Alcohol Abuse and Alcoholism,

The National Institute on Alcohol Abuse and Alcoholism,

National Institute on Drug Abuse,