Get a free, confidential consultation.

Teens Who Use Marijuana Risk Brain Damage

Teens Who Use Marijuana Risk Brain DamageMarijuana is one of the common names for cannabis, a group of closely related plant species that contain the active, mind-altering ingredient THC (tetrahydrocannabinol). Current scientific evidence indicates that the use of marijuana can produce a number of significant physical and mental/behavioral health risks, including breathing difficulties and heightened chances of developing a deeply disoriented mental state called psychosis. According to the results of a study published in July 2013 in the journal Neuropsychopharmacology, teenagers who use marijuana have unique risks for damaging their brain function in ways that last long into adulthood.

Marijuana Basics

Marijuana can refer to the flowers, leaves or stems of cannabis plants. Unlike another cannabis product, called hashish, these plant parts are dried but not artificially concentrated. In the past, this lack of artificial concentration meant that marijuana products had relatively low amounts of active THC. However, modern horticultural methods have given growers increasing control over the chemical composition of cannabis plants, and the THC content of the average marijuana sample has gone up relatively drastically over the last 40 years or so.

After a lull that lasted for about 15 years, marijuana use among teenagers started to increase in 2007, according to figures compiled by the National Institute on Drug Abuse. In 2012 (the last year available for statistical analysis), almost 23 percent of all U.S. high school seniors reported using the drug on a monthly basis, while 6.5 percent reported using marijuana on a daily basis. Seventeen percent of U.S. high school sophomores also report using the drug monthly. While some adults use marijuana for medical purposes under circumstances monitored by a doctor, teenagers and younger children have no legitimate access to this kind of legal use.

In addition to increased psychosis risks, modern researchers have linked adolescent marijuana use to mental health problems such as increased risks for anxiety and depression, increased risks for mood swings and uncontrolled outbursts of anger, increased risks for substance use/abuse and increased risks for suicidal thoughts and actions. When teen marijuana users develop mental health issues, they have a reduced tendency to respond well to medication, and also develop heightened risks for medication side effects. Compared to adolescents who don’t use marijuana or other illegal substances, teen marijuana users are also more likely to engage in unsafe sexual practices, have problems performing well in school, get involved in automobile accidents, develop thought or memory impairments, experience a decline in intelligence scores and experience a decline in drive or personal motivation.

New Findings

In the study published in Neuropsychopharmacology, a research team from the University of Maryland School of Medicine used mice to examine the long-term effects of teenage marijuana exposure on everyday brain function. Mice were chosen for the study due to their brain-related similarities with human beings, since no one can ethically expose human teens to marijuana or any other illegal drug. During the study, the University of Maryland researchers gave adolescent mice extremely small doses of THC for 20 days, then discontinued THC use and allowed the mice to grow up normally. For comparison’s sake, they also gave the same THC regimen to a group of adult mice that had not been exposed to the drug during adolescence.

After reviewing their findings, the authors of the study concluded that even small degrees of marijuana exposure during adolescence can damage the adult brain’s ongoing ability to perform such basic cognitive (thought-processing) tasks as properly using memory, making situation-appropriate judgments, controlling impulsive behavior, making decisions and planning for the future. They also concluded that marijuana exposure that only begins in adulthood does not appear to produce these thought-related problems.


The authors of the study in Neuropsychopharmacology believe that marijuana use has such uniquely harmful effects on the teenage brain because the part of the brain responsible for conscious thought processing undergoes much of its most important development during adolescence. In effect, the presence of THC in the brain can interfere with this development and produce lasting changes in normal brain function. The study’s authors also note that the mental disorder schizophrenia also impacts the same area of the brain as THC; this fact may help explain why marijuana users have increased risks for psychosis, which is the most serious, well-known schizophrenia symptom. In the future, doctors and researchers may be able to use their increased understanding of marijuana’s damaging brain effects to create more effective treatments for dealing with those effects in both teens and adults.

Posted on August 12th, 2013

Get a free, confidential consultation.
Call 844-876-5568 or fill out the form below.