Get Help & Answers Now

How can we help?

I'm ready to sign up! I have a few questions I want to refer someone Quiz: is Suboxone for me?

Marijuana & the Brain: Benefits, Dangers & Signs of Addiction

Elena Hill, MD, MPH profile image
By Elena Hill, MD, MPH • Updated Jun 7, 2022 • 12 cited sources

Marijuana is a naturally grown psychoactive substance that acts on brain cells. Those alterations make you feel relaxed and euphoric in many cases. However, side effects include confusion, paranoia, and depression. Marijuana is overall thought to be a relatively safe drug however it does have some risks when used frequently or in excess. Reach below to learn more about how marijuana works in the body.  

How Does Marijuana Work on Brain Cells?

The product we call marijuana is a plant with psychoactive properties. Marijuana leaves can be smoked, consumed in edible form, or used topically. Marijuana is made up of two main ingredients you should know about: THC and CBD. THC acts centrally in the brain, whereas CBD acts just in the body/peripherally and does not therefore have a psychoactive component. Pure marijuana contains both THC and CBD. However, THC and CBD can be extracted and used separately (you can obtain pure THC without CBD and pure CBD without THC). [8] 

Marijuana THC molecules attach to cannabinoid receptors in your brain. Once connected, they disrupt your brain’s natural communications processes.[1] They cause the brain to release amino acids and neurotransmitters and create feelings of relaxation and euphoria [2]. 

Marijuana & Your Brain: Short-Term & Long-Term Consequences

Marijuana has both short and long term consequences of use. 

Short-Term Marijuana Consequences

You may only feel the effect of marijuana for a few hours. But researchers can detect changes in brain cells for up to 24 hours.[3] Marijuana can impact:

  • Attention 
  • Coordination
  • Memory
  • Movement
  • Time perception

If you are high on marijuana, your judgment and reflexes can be altered. As a result, you should never drive or operate machinery while using marijuana. You are also at increased risks for accidents and self injury. 

Long-Term Marijuana Consequences 

The long term consequences of marijuana use are hard to know and vary depending on each individual’s genetics, use patterns, etc. 

In a study of 4,000 young adults tracked for over 25 years, researchers found that any exposure to marijuana during their lifespan resulted in lower scores of verbal memory.[4] The more marijuana people took, the lower their scores. 

Other research suggests that regular marijuana users have smaller brain grey matter volume, especially in the parts of the brain controlling:[5]

  • Decision-making
  • Emotion
  • Motivation

THC can alter core parts of your brain involved in long-term memory and focus.[1] These two changes make it harder for you to learn new things and perform complicated tasks.

Long term consequences of marijuana use tend to be worse if use is started at a younger age: A study of people who started using marijuana in adolescence had an average IQ loss of six to eight points. Those who used heavily as teenagers but quit as adults didn’t recoup the loss. Those who started to use it as adults didn’t have this issue. Therefore marijuana use at a young age may be associated with more serious outcomes than those who have a delayed onset of use. [4] 

There is also evidence that marijuana use, particularly heavy or daily use, can negatively impact memory long term. [10]. 

Potent strains of marijuana can cause psychotic episodes in some people. Researchers say smoking strong marijuana every day could increase your chances of psychosis by nearly five times when compared to never users.[6]

Repeated use can also increase your risk of mental health disorders, such as these:[6]

  • Anxiety
  • Depression
  • Substance use disorders

Research continues to clarify the link between marijuana use and poor mental health [7].

Does Marijuana have any health benefits? 

Many states authorize marijuana products for medical use for certain medical conditions. For example, there is good evidence that marijuana can help with certain seizure disorders[9, 11] Marijuana can also be a relatively safe and effective treatment for various chronic pain disorders, and is certainly preferable to more dangerous painkillers including narcotics in the long term treatment of chronic pain. 

Withdrawal From Marijuana 

Most people think of marijuana as not being very physiologically addictive, however it is undeniable that people who use marijuana daily and excessively can have mood changes and anxiety/depressive symptoms upon discontinuing use. Withdrawal symptoms form marijauana however are less severe than other substances and are never life threatening. 

Signs of Marijuana “Addiction”

About three marijuana users in 10 will develop a marijuana use disorder.[12] This is defined as using marijuana so frequently or in such high quantities that it impairs daily functioning and/or has negative consequences on a person’s life. 

These are signs of marijuana use disorder:[12]

  • Using more than you wanted to
  • Trying to quit, but finding that you’re unable to 
  • Spending a lot of time finding and using marijuana
  • Craving the drug
  • Continuing to use it even though it causes you problems in your daily life 
  • Prioritizing marijuana use over friends and family 
  • Using marijuana in high-risk situations like driving or operating machinery. 

If you’re trying to quit marijuana use and can’t seem to make the resolution stick, ask for help from a treatment team. You’ll get help with any unpleasant withdrawal side effects, and you’ll learn how to minimize or even discontinue use all together, depending on your goals. 

By Elena Hill, MD, MPH

Elena Hill, MD; MPH received her MD and Masters of Public Health degrees at Tufts Medical School and completed her family medicine residency at Boston Medical Center. She is currently an attending physician at Bronxcare Health Systems in the Bronx, NY where ... Read More

  1. How Does Marijuana Produce Its Effects? National Institute on Drug Abuse. July 2020. Accessed May 2022. 
  2. Cannabis and the Brain. Brain. June 2003. Accessed May 2022. 
  3. Brain Health. Centers for Disease Control and Prevention. October 2020. Accessed May 2022. 
  4. What Are Marijuana's Long-Term Effects on the Brain? National Institute on Drug Abuse. July 2020. Accessed May 2022. 
  5. Long-Term Effects of Cannabis on Brain Structure. Neuropsychopharmacology. March 2014. Accessed May 2022. 
  6. Is There a Link Between Marijuana Use and Psychiatric Disorders? National Institute on Drug Abuse. July 2020. Accessed May 2022. 
  7. Use of Marijuana: Effect on Brain Health. A Scientific Statement from the American Heart Association. February 2022. Accessed May 2022. 
  8. Beyond THC and CBD: The Science of Cannabinoids and The Brain. Inverse. Accessed May 2022. 
  9. Advocacy: Medical Cannabis CBD. Epilepsy Foundation. January 2021. Accessed May 2022. 
  10. Acute Effects of Naturalistic THC vs. CBD Use on Recognition Memory: A Preliminary Study. Journal of Cannabis Research. September 2020. Accessed May 2022. 
  11. Marijuana and the Developing Brain. American Psychological Association. November 2015. Accessed May 2022. 
  12. Addiction (Marijuana or Cannabis). Centers for Disease Control and Prevention. October 2020. Accessed May 2022.

Imagine what’s possible on the other side of opioid use disorder.

Our science-backed approach boasts 95% of patients reporting no withdrawal symptoms at 7 days. We can help you achieve easier days and a happier future.