Does Weed Kill Brain Cells?

does weed cause anxietyIt isn’t known whether weed, cannabis, or marijuana kills brain cells. And current research has produced conflicting results. Most studies consider the effects of tetrahydrocannabinol (THC) on the brain. THC is the psychoactive compound in weed that causes the “high” feeling. It’s just one of over 100 cannabinoids found in marijuana. In some cases, marijuana use can spark characteristics of addiction in users. Thus, addiction treatment may be necessary.

Your body naturally produces endocannabinoids, which are similar to cannabinoids. THC and these endocannabinoids both bind to the same receptors in the brain. When they bind to the receptors, they affect these bodily functions:

  • Mood
  • Sleep
  • Memory
  • Learning
  • Pain regulation
  • Metabolism and appetite
  • Reproductive functioning
  • Immune system functions
  • Cardiovascular functioning
  • Bone and muscle formation

Cannabinoids like THC and the naturally occurring endocannabinoids may have consequential effects on brain function and development. This is because the brain areas that control memory, learning, motor control, and sensory perception have high concentrations of the CB1 receptors, where the cannabinoids and endocannabinoids attach.

Short-Term Side Effects and Risks of Marijuana Use

Some of the possible short-term side effects of heavy marijuana use include:

  • Red or dry eyes
  • Dry mouth
  • Lung irritation
  • Rapid heart rate
  • Fatigue
  • Short-term memory problems
  • Problems learning or retaining information
  • Loss of coordination
  • Paranoia or anxiety

Long-Term Side Effects and Risks

The long-term risks and side effects linked to cannabis use include mood disorders, psychotic episodes, and neurocognitive impairment. Research is still going on but long-term marijuana use increase a person’s risk of substance use disorders and problems with memory and concentration. Several studies suggest that the use of marijuana can cause impairment in cognitive abilities. However, the amount of impairment and the duration depends on the age when the person began using, how much was typically used, and how long they used.

Marijuana and IQ Loss

does weed kill brain cellsA large study in New Zealand found that persistent marijuana use disorder with frequent use beginning in adolescence was linked with a loss of an average of 6 IQ points measured in mid-adulthood. And those who quit using marijuana as adults did not recover the lost IQ points.

Still, more research is necessary to determine whether marijuana use causes long-term IQ losses and whether factors that weren’t measured in the earlier research (such as the increasing amounts of THC) are important. Likewise, drawing definite conclusions about long-term effects on the human brain from previous studies is often limited by the facts that many participants use multiple substances, and there is not enough information about their mental functioning before the study.

Research available at this time offers some observation of the short-term effects but it’s hard to draw a definite conclusion regarding long-term effects. This is because many studies track small samples of people over short periods. Hopefully, this will change in the near future. The National Institutes of Health (NIH) began the Adolescent Brain Cognitive Development (ABCD) study in 2015 which seeks to understand how tobacco, alcohol, marijuana, and other drug use affects adolescent health and brain development.

What is Marijuana?

Also called, weed, pot, grass, and a large array of other slang names, is a greenish-gray mixture of the dried flowers of Cannabis sativa. People smoke marijuana:

  • In pipes
  • In hand-rolled cigarettes called joints
  • In water pipes sometimes called bongs
  • Rolled in cigar wraps called blunts

It can also be used to brew tea and is often mixed into food (edibles), mostly when it is sold or consumed for medicinal purposes.

The stronger types of marijuana include sinsemilla (from specially tended female plants) and concentrated resins that contain high doses of the active ingredients in marijuana. This includes honey-like hash oil, waxy budder, and hard shatter.  These have become popular among people who use them recreationally and medicinally.

The main psychoactive (mind-altering) chemical in marijuana is delta-9-tetrahydrocannabinol (THC). THC is responsible for most of the intoxicating effects and is found in the resin mainly produced by the leaves and buds of the female plant. Additionally, the plant contains more than 500 other chemicals. That includes more than 100 compounds that are chemically related to THC and are called cannabinoids.

How Does Marijuana Cause Its Effects?

The chemical structure of THC is similar to the brain chemical anandamide. This similarity allows the body to recognize THC and change normal brain communication. Anandamide works as a neurotransmitter because it sends chemical messages between nerve cells throughout the nervous system. They affect brain areas that control:

  • Memory
  • Thinking
  • Pleasure
  • Movement
  • Coordination
  • Sensory and time perception

The similarity makes it possible for THC to attach to the cannabinoid receptors in these areas of the brain and activate them. When this happens, it disturbs various mental and physical functions which causes the results described earlier.

THC also activates the brain’s reward system which includes areas that manage the response to healthy pleasurable behaviors like sex and eating. And the same as most other drugs that are misused, THC stimulates neurons in the reward system to release the signaling chemical dopamine at higher levels than normally seen in response to natural stimuli. This flood of dopamine basically “teaches” the brain to repeat the rewarding behavior. This helps explain why people may become addicted to marijuana.

5 Signs of Possible Marijuana Addiction

About 9% of people who use marijuana become dependent or addicted, according to the National Institute on Drug Abuse (NIDA). This means that they can’t stop using it even if it is causing harmful effects on their health, finances, career, or relationships. Although it isn’t linked to overdose deaths like other drugs, it can have some serious side effects.

Using marijuana can affect your motivation and decision-making negatively. It can cause a loss of interest in social and recreational activities you used to enjoy. Losing interest in setting and achieving goals could be a sign of marijuana addiction.

When you put less effort into your family, friends, or romantic relationships because of marijuana use, it is a sign of a use disorder. Are you pulling away from people who don’t approve of your marijuana use? You might be choosing the drug regardless of their concern for you.

Individuals who are dependent on marijuana notice withdrawal symptoms whenever they stop using it. Withdrawal symptoms include:

  • Anxiety
  • Irritability
  • Restlessness
  • Depressed mood
  • Sweating, tremors, or chills

As you become dependent on the drug, your tolerance will increase. This means that you need to use more of it to get the same effects. It’s a sign of dependence and one of several signs of drug addiction.

People who are dependent on or addicted to marijuana aren’t able to stop even if they notice harmful side effects. This may include not being able to meet obligations at work or school or keeping up with responsibilities at home. If you are experiencing any of these symptoms, you should get professional help.


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Treating a Marijuana Addiction (Marijuana Use Disorder)

Marijuana use disorders (MUDs) are similar to other substance use disorders. The average adult getting treatment for MUD has used marijuana nearly every day for more than 10 years and has attempted to quit more than 6 times. Individuals with MUD, particularly adolescents, frequently also suffer from other psychiatric disorders (dual diagnosis). They may also be using or addicted to other substances such as alcohol or cocaine.

Studies show that effectively treating mental health disorders with standard treatments that involve medications and behavioral therapies can help reduce marijuana use. This is especially true among people involved with heavy use and those with more chronic mental disorders. These behavioral treatments have been proven to be effective:

  • Cognitive-behavioral therapy (CBT)–This type of therapy teaches people methods to help them identify and correct problem behaviors. This helps strengthen self-control, stop drug use, and focus on other issues that often co-occur with them.
  • Dialectical behavior therapy (DBT)–DBT is a form of CBT that focuses more on emotions and relationships. In DBT you learn acceptance and change.
  • Motivational enhancement therapy–This is designed to produce rapid internal motivations for change. Instead of treating the individual, it activates their own internal reasons for change and taking part in treatment.

At this time, the FDA hasn’t approved any medications for the treatment of MUD. But since sleep problems are a prominent issue in marijuana withdrawal, some studies are looking at the effectiveness of medications that help sleep. Other medications that look promising are an anti-anxiety medication called buspirone and an anti-epileptic drug called gabapentin. These medications may improve sleep and executive function (memory, flexible thinking, and self-control).

Other substances being studied include:

  • A nutritional supplement
  • Chemicals called FAAH inhibitors which can reduce withdrawal symptoms
  • A substance that can interact with cannabinoid receptors to restrict THC’s rewarding effects

Because marijuana is not as hard on the brain as many “harder” drugs, many people are able to quit without a detox or residential treatment. However, for people who live in an environment that makes it extremely difficult stop using, an inpatient or residential treatment center may be the best choice. Available  treatment programs include:

  • Residential treatment: Residential treatment helps eliminate non-ideal settings and daily triggers. Living in a structured drug-free setting creates a situation where you can focus on getting well.
  • Outpatient programs: For people with a stable home situation, an outpatient program may be all you need to overcome marijuana addiction. There are several levels of outpatient care and the frequency and duration may vary by treatment center:
  • Partial Hospitalization Program (PHP): the highest level of outpatient treatment, PHP compares to residential care except you are able to go home each night.
  • Intensive Outpatient Program (IOP): At this level, you will attend sessions about 3 times per week for about 3 – 4 hours per day.
  • Outpatient Program (OP): A standard outpatient program will require several hours of treatment per week. OPs are most effective when used as a step-down program from a higher level of care.

Allow Achieve Wellness & Recovery to Help You

Marijuana use is gradually becoming accepted just like alcohol use, so many people don’t think of marijuana as an addiction problem. But, just like alcohol, marijuana is no joke and it can become an addiction and ruin a life. There’s no reason to let that happen. Achieve Wellness and Recovery can offer a full continuum of care from residential treatment to sober living and aftercare.

Are you struggling with an addiction to marijuana? Do you have a loved one who is? You deserve the best treatment available and the best opportunity to succeed. Our experienced, fully licensed professionals are immediately available to talk to you or you may schedule an appointment. Contact us today.

  1. Ng T, Gupta V. Tetrahydrocannabinol (THC). In: StatPearls. StatPearls Publishing; 2022. Accessed January 1, 2023.
  2. Karila L, Roux P, Rolland B, et al. Acute and long-term effects of cannabis use: a review. Curr Pharm Des. 2014;20(25):4112-4118. doi:10.2174/13816128113199990620
  3. Power E, Sabherwal S, Healy C, O’ Neill A, Cotter D, Cannon M. Intelligence quotient decline following frequent or dependent cannabis use in youth: a systematic review and meta-analysis of longitudinal studies. Psychol Med. 2021;51(2):194-200. doi:10.1017/S0033291720005036
  4. NIH’s Adolescent Brain Cognitive Development (ABCD) Study. Alcohol Res. 2018;39(1):97.
  5. National Institute on Drug Abuse. Is marijuana addictive? National Institute on Drug Abuse. Published 2020. Accessed January 1, 2023.
Amanda Stevens, BS

Amanda Stevens, BS

Amanda is a prolific medical content writer specializing in eating disorders and addiction treatment. She graduated Magnum Cum Laude from Purdue University with a B.S. in Social Work. As a person in recovery from disordered eating, she is passionate about seeing people heal and transform. She writes for popular treatment centers such as Infinite RecoveryAscendant NY, The Heights Treatment, New Waters RecoveryGallus DetoxRecovery Unplugged,  Ocean RecoveryRefresh Recovery and adolescent mental health treatment center BasePoint Academy. In her spare time she loves learning about health, nutrition, meditation, spiritual practices, and enjoys being the a mother of a beautiful daughter.

Last medically reviewed January 1, 2023

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