Does Weed Kill Brain Cells? The effects of marijuana on teenage brain

A 2019 study shows that around 37% of U.S. teenagers have tried cannabis at least once, and 22% have used it in the last month. Due to this, more and more people are asking an important question: Does weed kill brain cells?

Nowadays, more teenagers are using weed, stirring both interest and worries. As cannabis becomes legal and more accepted in many places in the United States, it’s attracting a lot of attention, especially from individuals aged between 13 – 19. In these times, it’s important to understand how cannabis affects health, especially how it might change brain function and development and its long-term effects on cognitive function.

This article looks into a critical concern of parents and guardians all over the globe; “Does weed kill brain cells?” Taking information from scientific studies and trusted sources, it focuses on the effects of cannabis on teenagers and tries to clear up common misconceptions surrounding it.

Debunking Myths: Does Weed Kill Brain Cells?

Addressing the “Brain Cell Death” Claim:

A study involving 799 people from the IMAGEN cohort found no clear link between the thickness of the brain’s outer layer and past cannabis use (when the study began). This suggests that the differences in brain structure present weren’t there before the participants started using cannabis.

However, the study did find that those who increased their cannabis use over time had more thinning in the left and right prefrontal cortices of their brains. These areas have many cannabinoid 1 receptors and change a lot in thickness during the teenage years.

While cannabis is not likely to kill brain cells, frequent use could still impact how the brain develops in teenagers.

What is the Difference Between THC and CBD?

THC (tetrahydrocannabinol) and CBD (cannabidiol) – these two main ingredients compose cannabis; however, they induce distinct side effects on the brain.

THC: The substance THC, present in cannabis, mimics natural brain chemicals and alters sensory perception, mood, movement and memory. Its effects commonly induce a euphoric ‘high’ that numes rous individuals experience post-consumption of cannabis.

CBD: The substance CBD, often misunderstood for inducing a euphoric state like THC, notably differs in its effects: it does not produce the characteristic ‘high’ associated with marijuana usage.

Moreover, CBD is hypothesized to offer brain protection; this further distinguishes its pharmacological profile from that of THC which primarily acts as a psychoactive agent.

What are the Effects of Cannabinoids on the Brain?

Below we discuss short-term and long-term effects of cannabinoids on brain development/behavior.

Short-Term Effects:

  • Memory Impairment: People might find it hard to recall recent events.
  • Motor Control Problems: This can lead to difficulties in coordination and movement, affecting activities such as driving.
  • Increased Appetite: Often known as “munchies,” this is a strong desire to eat, often junk food.
  • Higher Heart Rate: Heartbeats can increase significantly, which is a concern for those with heart conditions.
  • Changed Sleep Patterns: This includes changes in how well and how long people sleep, with less REM sleep.
  • Less Pain: Cannabis can reduce pain, which is why it’s used in medical settings.

Long-Term Effects of Cannabinoids on Development/Behavior:

Cognitive Functions:

  • Attention: There might be a drop in how well people can focus and concentrate.
  • Memory: Both short-term and long-term memory could be affected.
  • Learning: It might become harder to learn and remember new information.
  • Decision-Making: People might find it harder to make good decisions and solve problems.

Mental Health:

  • Increased Anxiety Risk: Especially in those already likely to have anxiety.
  • Depression: There might be an increase in depression symptoms.
  • Psychosis Risk: Especially for those with a family history of mental health issues.

Brain Development:

  • Changes in Brain Growth: Regular use during teenage years might change how the brain develops and matures.

Smoking vs. Other Consumption Methods:

The method of cannabis consumption can influence its health risks.

Smoking Weed



Immediate effects due to inhalation

Similar immediate effects of smoking

Absence of harmful substances found in smoke

Exposure to harmful substances found in smoke

Potentially reduced exposure to harmful smoke substances

Delayed onset of effects, leading to possible overconsumption

For more detailed information, you can explore the sources from the CDC and Psychology Today, which provide comprehensive insights into the effects of cannabis on the brain.

Seeking Expert Opinions

When looking at how weed affects the developing brain, it’s really important to listen to what experts in fields like neuroscience, psychology, and addiction have to say.

Newport Academy on Medical Marijuana and Teenagers:

Newport Academy points out that while marijuana might have some health benefits for adults, it’s usually not a good idea for teenagers to use it.

Based on a 2017 report from the American Academy of Pediatrics, experts stress that children need to be protected from the impact of marijuana becoming legal. The AAP strongly recommends against teens using medical marijuana because of the risks it might have during this important time of growth.

Healthline on Cannabis and Psychiatric Disorders in Teens:

A study from Columbia University, reported by Healthline, shows that teenagers who use cannabis for fun are more likely to have mental health issues like depression and thoughts of suicide. This risk is higher in teens who use cannabis than in those who don’t.

Dr Bonnie Halpern-Felsher, a developmental psychologist at Stanford, says that for older teenagers or young adults who are more likely to have psychosis because of their genes or family history, using cannabis can trigger these mental health problems.

Psychology Today on Cannabis-Induced Psychosis:

Psychology Today has seen more cases of psychosis caused by cannabis, especially when using stronger types. People often feel very paranoid and confused and might need therapy to get better.

While it’s not completely clear how cannabis use is linked to schizophrenia, experts agree that the brain is very sensitive in the late teens and early 20s. There’s a worry that using cannabis during this key time of growth, especially stronger kinds could have a big and lasting effect on mental health.

All these expert views come to a similar conclusion: using cannabis, especially during adolescence, can be very risky. The developing brain is really vulnerable to the effects of cannabis substance abuse, and the chance of long-term mental and thinking problems means we should be very careful about teenagers using it.


Can Weed Kill You?

It’s extremely rare for cannabis use alone to cause death. However, it can lead to risky behaviours, like impaired driving. There are no cases where someone has died from a cannabis overdose alone.

What Does Weed Do to Your Body?

The THC found in weed can change your perception, mood, and movement, make you hungrier, and change your heart rate. effects depend on how strong the cannabis is, how you use it, and personal factors.

Can You Die from Weed?

Dying just from using cannabis is very unlikely. But, it can make you do risky things or make some health problems worse, which might increase the risk of harm or, in rare situations, cause death.

Is Weed Bad for Your Brain?

Cannabis can change how your brain works in the short term and the long term. Short-term effects include memory and cognitive changes. Long-term use, especially when you’re young, can change how your brain develops and increase the chance of mental health issues.

What Does THC Do?

THC, the part of cannabis that affects your mind, sticks to certain brain receptors. This changes brain functions, affecting mood, perception, thinking, and movement.

How Does Weed Affect the Brain of a Teenager?

In teenagers, weed can change how the brain develops. Regular use of cannabis can alter areas that are important for decision-making, memory, and learning. It can also raise the chance of mental health problems like depression or anxiety.

What are the Effects of Smoking on the Teenage Brain?

Smoking cannabis can change thinking abilities and brain structure and might make mental health issues worse. Smoking also exposes the brain to other substances that might affect brain health.


Understanding whether weed kills brain cells is not straightforward. Current research shows that cannabis, mainly THC, may not directly kill brain cells. However, it can impact brain function and structure, particularly in teenagers. This can lead to changes in thinking abilities and the possibility of mental health issues.

It’s a good idea to look at this issue from a bird’s-eye view. While we’re still learning about the long-term effects of cannabinoids on brain development and behaviour, the current evidence suggests we should be careful when using cannabis.

As researcher continue their quest for a definitive answer, it’s important for everyone – teenagers, parents, teachers, or anyone interested in cannabis – to stay informed and cautious about its effects.


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  2. Matthew D Albaugh, Jonatan Ottino-Gonzalez, Amanda Sidwell, Claude Lepage, Anthony Juliano, Max M Owens, Bader Chaarani, Philip Spechler, Nicholas Fontaine and others. (Jun 16, 2021)
  3. National Center for Injury Prevention and Control, Centers for Disease Control and Prevention (October 19, 2020). Brain Health.
  4. Newport Academy (March 30, 2021). The Effects of Marijuana Legalization on Teenagers.
  5. Mountainside Treatment Center (July 21, 2023). Cannabis and the Teenage Brain.