4 Ways Cannabis Harms the Teenage Brain

4 Ways Cannabis Harms the Teenage Brain

As the legalization of cannabis expands in the U.S., interest is skyrocketing in the drug’s potential as a therapy for physical and psychological issues. Many teens see legalization as a green light to light up. But even though some research suggests possible therapeutic effects for people with anxiety, depression, and PTSD, other studies point to marijuana’s negative effects on young, developing brains.

1. Increases the risk of depression and suicidal behavior

Using marijuana before the age of 18 significantly increases the risk of developing depression, suicidal thoughts, or suicide attempts in young adulthood, according to a 2019 review of 11 studies involving more than 23,000 people. The study concluded, “This is an important public health problem and concern, which should be properly addressed by health care policy.”

2. Impairs cognitive function

Decades of research shows that marijuana impairs brain functions, such as memory, learning, and attention. Adolescents who use cannabis frequently have been shown to experience a decline in IQ, perform more poorly in school, and are more likely to drop out. Later in life, they have higher rates of unemployment and tend to have lower rates of satisfaction with their life in general.

3. Disrupts the brain’s maturation process

During the teenage years, the brain is undergoing rapid development. A process called myelination takes place, coating neurons with a protective white-colored sheath that helps speed communication in the brain. This important process, which gives the brain’s white matter its color, isn’t completed until a person’s mid-20s. Heavy cannabis use as an adolescent can interfere with this process, damage the brain’s white matter, and result in a higher incidence of impulsivity, especially in teens who started smoking marijuana prior to the age of 16.

4. Reduces blood flow to the brain

A 2016 brain imaging study on nearly 1,000 cannabis users showed overall decreased blood flow compared to a healthy group of nonusers. The brain region most likely to be affected in marijuana users in this study was the hippocampus, which is involved in memory, moods, and learning. Low blood flow on brain SPECT imaging has also been seen with ADHD, depression, suicide, bipolar disorder, schizophrenia, and more.

Any addictive substance can ruin lives and ruin families, and marijuana is no exception. Amen Clinics takes a 360-degree approach to treating addictions — addressing any co-existing conditions and using a whole suite of strategies to enhance overall brain health.

If you’re concerned about an adolescent’s cannabis use, reach out today to make an appointment online or by calling 888-288-9834.


  1. Regarding your article on Cannabis and the Teenage Brain, would that also apply to CBD supplements or just marijuana with THC?

    Comment by Heather Zwicker — April 15, 2019 @ 4:06 AM

  2. Thanks for your statements about cannabis! I appreciate your observations and opinions and will repeat them to my clients who come to me for counseling. I’m sad that kids are using it more and more!

    Dr. Susan Smart, Licensed Psychologist

    Comment by susan smart — April 15, 2019 @ 5:55 AM

  3. Is there a way to revive the hippocampus if marijuana was used when they were teenagers and now in their 50’s and 60’s?

    Comment by Karen — April 15, 2019 @ 6:19 AM

  4. We were told that CBD oil capsules help Parkinson’s patients with processing problems. My husband had a brain scan and it showed a deficiency of oxygen to the brain. He has been on this. Should we stop.
    Thank you for your help.

    Comment by pat Schaible — April 15, 2019 @ 12:13 PM

  5. I love all your articles and progressive knowledge that you share. It’s unfortunate that you have only offered help for the wealthy with your cost……..

    Comment by Cynthia — April 15, 2019 @ 1:42 PM

  6. Great article as usual. From personal experience I don’t agree with point 1and 2 and think there is still a lot to discover on this front. I only became a functional human being once I started smoking Canabis. Growing up I had severe memory problems and leaning disabilities and pot helped me overcome many things. I also think that alcohol and pharmaceuticals are far more dangerous for a growing brain and other vital organs and would like to see more research on that.

    Comment by Madalena — April 15, 2019 @ 10:19 PM

  7. You’re right and unfortunately GREED is the name of the game now, even in holistic med.

    Comment by Frank — April 16, 2019 @ 3:08 PM

  8. Please a professional answer
    does medical Canabis
    have the same effect?

    Dr. Amen;
    How much would a consultation with your clinic cost and would insurance cover it??

    Comment by Diana — April 24, 2019 @ 8:50 PM

  9. Hi Dr Amen,

    I truly appreciate all your ~continued~ efforts over the years to {Get The Info Out about how BAD marijuana is for the developing brain…through the age of 25}…and how you continue to TRY to help all those to LEARN the Truth. I am sure my ADD brain would be much worse than it already is if I were to smoke pot or ingest THC of any kind and perhaps damage was done back in my teens years ago.

    Those who REFUSE to Listen to your advice, medical opinion and the Research that is plain as the nose on their faces, are damaging their brains and don’t even care. As you know; DENIAL is what an addict or anyone else for that matter must first STOP doing in order to LEARN about the disease of Addiction. The mind is a terrible thing to waste. Keep posting these articles and even MORE frequently for they are severely needed in our country right now. Even if only 1 person listens, it would be worth all your efforts~


    Comment by Penny — May 25, 2019 @ 12:47 PM

  10. I definitely agree with points 1 and 2, and I’d say that that may have been my case very well as a teen. I was often really depressed and experienced a hard time staying focused in the classroom.
    I believe its important to also focus on parenting, and making it available for teens to understand how to cop w things as children, while many of them are told by friends that they should “just get high” when they simply aren’t being educated on ways to handle life at that age.
    Also, I wanted to say that cannabis isn’t necessarily “addictive”, the way that we can say something like heroin is. However, we CAN say that cannabis can be ABUSED, like any other MEDICATION (such as pain relievers which have high abuse rates). I believe further education on proper cannabis moderation in your lifestyle is upright important.

    This article was however very interesting, and I’m glad that I came to check out these comments from the Academy.

    ~Cecil Nichole

    Comment by Cecil Nichole — April 12, 2020 @ 7:26 PM

  11. I started smoking pot back in the 60’s when I was 14. I smoked daily to get high. After high school I went into carpentry. After a couple years I opened my own remodeling company. I worked pretty much hands on, 12 hr days, 7 days a week until 2008 and was quite successful- even being featured in a number of home magazines. I can definitely say weed did not make me lazy nor unmotivated. I will concede that most of what we had was not as strong as what is being produced today

    Comment by Sour D — April 13, 2020 @ 2:46 AM

  12. It is a great problem in Latinoamerica where the black market target the young people and push them to addictions. My thoughts are more education and legal market is equal to better control on the consumption and cannabis distributions.

    Comment by Rafael — April 13, 2020 @ 10:28 AM

  13. Hi Heather
    Would be interested in the reply to your question as I don’t see any of these queries receiving responses. I am a CBD Coach for a company in California. Thank you.

    Comment by Mary Williams — April 24, 2020 @ 10:02 AM

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