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Marijuana and Brain Development: What You Should Know

By Lauren Katims
Medically Reviewed by Jennifer Casarella, MD on December 18, 2021
Because marijuana has significant impacts on a developing brain, there is a risk of some mental health and/or neurological problems.

Marijuana use can cause long-term effects on a developing brain since a teenage brain is not yet fully mature.

According to a 2019 review published by American Addiction Centers, during adolescence and young adulthood, the brain forms new connections between brain cells and different regions of the brain. This helps define your personality, ability to focus, and how you experience pleasure and pain. The adolescent brain also makes many connections that help you grow into a social and intellectual adult.

Chronic marijuana use and exposure to its active ingredient tetrahydrocannabinol (THC), can slow down this growth, potentially causing long-term damage to the brain. “Adolescents are the age group most vulnerable to its negative effects,” Linda Richter, PhD. and vice president of Prevention, Research, and Analysis at the nonprofit organization, Partnership to End Addiction tells WebMD Connect to Care. 

“The strength of THC is also much higher today than it was decades ago. In fact, marijuana addiction is the most common diagnosis among teens admitted to addiction treatment programs,” Richter says.

Your Brain on Marijuana

According to a 2019 review published by the National Institute on Drug Abuse, researchers are still studying how long marijuana's effects last and whether or not some changes may be permanent. Here are some key personality changes to look for:

Short-Term Effects of Marijuana Use  

  • A decrease in alertness and focus
  • Lower motivation levels
  • Impaired memory
  • Lower desires to be social
  • Increase depression and suicidal thoughts
  • Withdrawal symptoms triggered when not taken

Long-Term Effects of Marijuana Use  

  • Lower IQ score in adulthood
  • Learning and memory impairment
  • Altered responses to pleasure and stress
  • Increase risk for psychosis including schizophrenia
  • Risk of developing a dependency on other drugs

Don’t Wait. Get Help Now.

If you or a loved one are struggling with marijuana addiction, WebMD Connect to Care Advisors are standing by to help.

Treatment & Resources for Marijuana Addiction