Casual Marijuana Use and the Brain

Young people who are casual smokers of marijuana experience potentially harmful changes to the brain, with drug altering regions of the mind related to motivation and emotion. Learn more about how casual marijuana use affects the brain.

Young People and Marijuana

A study published in the Journal of Neuroscience looked at research projects focused on chronic, heavy users of cannabis. The collaborative effort between Northwestern University’s medical school, Massachusetts General Hospital and Harvard Medical School demonstrate a direct correlation between the number of times users smoked and had abnormalities in the brain. The changes were most prominent in young people between the ages of 18 to 25.

Where Changes Occur

The study focused on identifying changes to the nucleus accumbens and nucleus amygdala, regions of the brain key to regulation of emotion and motivation. Researchers discovered changes to volume, shape and density of those brain regions. More studies are needed to determine how changes may have long-term consequences and whether it can be fixed with abstinence. Some researchers believed future motivation to achieve goals could be negatively impacted.

Effects of Medical Marijuana

Access to marijuana is greatly increasing and expanding following votes in Washington state and Colorado to legalize recreational use. The drug remains illegal under federal law. Medical marijuana is allowed in 20 U.S. states. Legalization advocates make the argument marijuana is safer than alcohol which is in some ways impacting the way young people view marijuana use.

Drinking and Use

Research is also being done into the effects of marijuana use with alcohol. It alters the brain while researchers are not even sure how it happens. Mental rewiring is seen in users of marijuana along with physical changes in the brain. Marijuana use impacts young, developing brains with some recommendations stating only people under 30 should use it to manage pain from a terminal illness. The harmful effects can potentially change the way the brain functions impacting emotion, motivation and other things which have lifelong consequences.


The Villa helps individuals of all ages find support for addiction to drugs or alcohol. If you are struggling to quit using marijuana or need help for a loved one, call us. We are here to help guide you to the best treatment available for your individual situation.