The Damaging Effects of Cannabis on the ADHD Brain
Cannabis use has grown in popularity among people with ADHD, some of whom report that marijuana helps them manage symptoms of anxiety, rejection sensitive dysphoria, and poor sleep without a prescription medication. What many teens and adults do not realize is that cannabis consumption is associated with dangerous risks — like cannabis use disorder — that disproportionately affect ADHD brains.
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Cannabis is used by a startling number of people with attention deficit hyperactivity disorder (ADHD). Studies show that more than half of daily and non-daily cannabis users have ADHD 1 , and about one-third of adolescents with ADHD report cannabis use 2 . People with ADHD are also three times as likely as their neurotypical peers to have ever used marijuana. 3
As with other popular substances, cannabis is commonly abused. In fact, the risk of developing cannabis use disorder (CUD), a problematic pattern of cannabis use linked to clinically significant impairment, is twice as high in people with ADHD 3 . Contrary to popular belief, individuals can be mentally and chemically dependent on and addicted to cannabis. Contemporary marijuana has concentrations of THC higher than historically reported, which exacerbates this. What’s more, the adverse effects of cannabis are especially amplified in people with ADHD.
What are the Negative Effects of Cannabis?
Tetrahydrocannabinol (THC), one of cannabis’ active compounds, inhibits neuronal connections and effectively slows the brain’s signaling process. THC also affects the brain’s dendrite architecture, which controls processing, learning, and the overall health of the brain. Science has not yet fully determined whether THC’s effects are reversible; some parts of the brain show healthy neuronal growth after cannabis use stops, but other parts do not.
Short-term and long-term cannabis use also impairs:
- Motivation (hampering effect)
- Memory, especially in people under 25, by altering the function of the hippocampus and orbitolfrontal cortex, where much of memory is processed
- Performance on complicated task performance with many executive steps. Studies have shown, for example, that driving ability, even while not under the influence, can be impaired in regular marijuana users
Cannabis use may also lead to the following health-related impairments:
- Chronic bronchitis
- Chronic obstructive pulmonary disease (COPD)
- Cannabinoid hyperemesis syndrome (characterized by severe bouts of vomiting and dehydration)
- Elevated resting heart rate
Cannabis use may exacerbate disorders like paranoia, panic, and mood disorder. Studies have also found that increased cannabis consumption can uniquely contribute to elevating suicide risk, even when controlling for underlying mental health disorders, like mood disorder or anxiety 4 5 . Individuals who begin regular cannabis use also exhibit more suicidal ideation, even when controlling for pre-existing mood disorders, studies show. 6 7
What is Cannabis Use Disorder (CUD)?
Cannabis is addictive — 9 percent of people who use cannabis regularly will become dependent on it 8 . This figure rises to 17 percent in those who start using cannabis in adolescence. 9
CUD can develop after extended cannabis use. It is diagnosed when at least two of the following occur within a 12-month period:
- Taking cannabis in larger amounts over longer periods of time
- Difficulty quitting cannabis use
- Strong desires or cravings to use cannabis
- Lots of time spent trying to obtain, use, or recover from cannabis
- Problems with work, school, or home because of interference from cannabis use
- Social or interpersonal problems due to cannabis use
- Activities given up or reduced because of cannabis use
- Recurrent cannabis use in physically hazardous situations, such as driving
- Physical or psychological problems caused or exacerbated by cannabis use
- Tolerance to cannabis
- Withdrawal from cannabis
How Does Cannabis Affect the ADHD Brain?
Cannabis use impairs areas and functions of the brain that are also uniquely impaired by ADHD.
The substance’s negative effects are most harmful to developing brains. Many studies show that usage earlier in life, particularly before the age of 25, predicts worse outcomes. One study found that heavy marijuana use in adolescence was associated with a loss of 8 IQ points, on average, in adulthood 10 . Another study found that people under age 18 are four to seven more times at risk for CUD compared to adults. 11
People with ADHD, whose brain development is delayed by slowly maturing frontal lobes, are thus more vulnerable to cannabis’ effects on neuronal connections. Some of these impairments may be irreversible.
Cannabis can also interact significantly with some ADHD medications. Research studies have shown that methylphenidate (Ritalin, Concerta) reacts significantly with the substance, and can cause increased strain on the heart. 12
Other studies show that the use of cannabis can decrease the effect of a stimulant medication 13 . An individual trying to treat their ADHD with stimulants is actually placing themselves at a disadvantage, since the cannabis is impacting them negatively and making the medication less effective.
The increased risk of suicide associated with cannabis use further complicates marijuana among individuals with ADHD, who already face an elevated risk for suicide compared to neurotypical individuals 14 .
What Draws People with ADHD to Cannabis?
Cannabis activates the brain’s reward system, and releases dopamine at levels higher than typically observed. In low-dopamine ADHD brains, THC thus can be very rewarding.
Many people with ADHD also claim that cannabis helps them focus, sleep, or seemingly slow the pace of their thoughts. One analysis of internet threads found that 25 percent of relevant posts described cannabis as therapeutic for ADHD, while 5 percent indicated that it is both therapeutic and harmful 15 . Despite some users reporting short-term improvement in symptoms, there is currently no evidence that suggests cannabis is medically or psychologically helpful for managing ADHD in the long-term.
Cannabis’ increased availability and legalization have increased accessibility; many cannabis products are falsely marketed as medicinal for ADHD.
Also contributing to an increased likelihood of cannabis use and CUD among individuals with ADHD is the prevalence of low self-esteem, sleep problems, poor impulse control, and sensation-seeking tendencies in this population.
How is Cannabis Use Disorder Treated in People with ADHD?
There is no approved medication to treat CUD — treatment generally means teaching patients strategies to maintain sobriety. Treatment can include talk therapies, like cognitive behavioral therapy (CBT) and dialectical behavior therapy (DBT), and participating in support groups like Marijuana Anonymous.
One small but insightful study looking at motivations to quit cannabis use in a group of adults with ADHD found that saving money was a major contributing factor 16 . The same study found that the most common strategy for maintaining abstinence was breaking social connections with people who smoke marijuana.
Treating and targeting ADHD itself in a patient that has CUD is also essential. Stimulant medication can be implemented as part of ADHD treatment, and it is not considered a violation of sobriety.
How Should a Parent Help a Teen with ADHD Who Is Using Cannabis?
It’s normal for parents to experience a range of emotions after discovering that their child is using cannabis. The initial gut reaction or emotion is understandably anger and disappointment, but it’s best to release these feelings prior to engaging in conversation. Any dialogue with teens must be done in a controlled, calm way — teens will not listen to parents who are yelling and blurting out things they will later regret.
Seeking consultation with a doctor, pediatrician, or therapist who has experience in substance abuse can help, especially for parents who are struggling with their owns feelings and reactions toward their child.
The next step is for parents to educate themselves on cannabis and how it can be appealing. Parents should try to proactively see what their child might be experiencing, and why they might have turned to the substance. When the conversation does start, parents should work deliberately not to shame their child, and instead focus on understanding their child’s experience on cannabis.
Parents should calmly ask questions like:
- “I found this and I’m concerned, but I’d like to know what the appeal of this is for you?”
- “What does this do for you?”
- “How did you feel the very first time that you did this?”
While parents are encouraged to have calm and thoughtful conversations with their teen, they should also set boundaries and consequences for substance use to remind their child that it is not acceptable. Without shaming, parents must establish rules that discourage substance use, especially in the household.
Many parents will say that they would rather have their child smoke in the house than outside with others. But this mentality doesn’t stop teens from smoking or using anywhere else. Instead, allowing at-home use communicates a sense of permission associated with substance use.
If teens say they are simply experimenting, they should know that experimentation can quickly turn into something more dangerous. Parents should inform them that teens with ADHD are at higher risk for addiction. Teens should also be aware, if they aren’t by this point, of any family history of addiction, which also has a genetic component.
Placing limits on smoking can create some backlash. Teens and young adult may be so gripped by the substance they they are willing to lie about using it to parents. Parents should approach their child if they suspect they are using, even after rules are in place, but should keep in mind that this substance, like any, can have people not always be truthful. That’s very different from thinking that their child can’t be trusted and is a liar.
Children should be reminded that they are loved and that their health is most important. Smoking marijuana doesn’t mean that parents have failed or that they’ve done a bad job with their children. There’s a terrible stigma on addiction surrounding character and morality — it’s important to remember that teens aren’t using drugs because they are bad people. Very, very good people are addicted to substances or experiment with them.
The information in this article is based on Dr. Roberto Olivardia’s two-part Marijuana and the ADHD Brain webinar series. The first part, “Marijuana and the ADHD Brain: How to Identify and Treat Cannabis Use Disorder in Teens and Young Adults” was broadcast live on February 26, 2020. “Marijuana and the ADHD Brain, Part 2” was broadcast live on March 26, 2020.
1 Loflin, M. et. al. (2014) Subtypes of Attention Deficit-Hyperactivity Disorder (ADHD) and Cannabis Use, Substance Use & Misuse, 49:4, 427-434, DOI: 10.3109/10826084.2013.841251
2 Molina, B. S. et. al. (2013). Adolescent substance use in the multimodal treatment study of attention-deficit/hyperactivity disorder (ADHD) (MTA) as a function of childhood ADHD, random assignment to childhood treatments, and subsequent medication. Journal of the American Academy of Child and Adolescent Psychiatry, 52(3), 250–263. https://doi.org/10.1016/j.jaac.2012.12.014
3 Lee, S. et. al. (2011). Prospective association of childhood attention-deficit/hyperactivity disorder (ADHD) and substance use and abuse/dependence: a meta-analytic review. Clinical psychology review, 31(3), 328–341. https://doi.org/10.1016/j.cpr.2011.01.006
4 W. Pedersen, “Does cannabis use lead to mood disorder and suicidal behaviors? A population-based longitudinal study,” Acta Psychiatrica Scandinavica, vol. 118, no. 5, pp. 395–403, 2008.https://doi.org/10.1111/j.1600-0447.2008.01259.x
5 Schmidt, K., Tseng, I., Phan, A., Fong, T., & Tsuang, J. (2020, Feb.). A Systematic Review: Adolescent Cannabis Use and Suicide. Addictive Disorders & Their Treatment. doi: 10.1097/ADT.0000000000000196
6 H. Chabrol, J. D. Mabila, and E. Chauchard, “Influence of cannabis use on suicidal ideations among 491 high-school students,” Encephale, vol. 34, no. 3, pp. 270–273, 2008. Doi : 10.1016/j.encep.2007.04.002
7 Raja, M., & Azzoni, A. (2009). Suicidal ideation induced by episodic cannabis use. Case reports in medicine, 2009, 321456. https://doi.org/10.1155/2009/321456
8 Lopez-Quintero, C., et. al. (2011). Probability and predictors of transition from first use to dependence on nicotine, alcohol, cannabis, and cocaine: results of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Drug and alcohol dependence, 115(1-2), 120–130. https://doi.org/10.1016/j.drugalcdep.2010.11.004
9 Volkow, N. D. et. al. (2014). Adverse health effects of marijuana use. The New England journal of medicine, 370(23), 2219–2227. https://doi.org/10.1056/NEJMra1402309
10 Meier, M, et. al. (2012). Cannabis use and neuropsychological decline. Proceedings of the National Academy of Sciences. 109 (40) E2657-E2664; DOI: 10.1073/pnas.1206820109
11 Winters, K. C., & Lee, C. Y. (2008). Likelihood of developing an alcohol and cannabis use disorder during youth: association with recent use and age. Drug and alcohol dependence, 92(1-3), 239–247. https://doi.org/10.1016/j.drugalcdep.2007.08.005
12 Kollins, S. et. al. (2015, Jan). An exploratory study of the combined effects of orally administered methylphenidate and delta-9-tetrahydrocannabinol (THC) on cardiovascular function, subjective effects, and performance in healthy adults. Journal of substance abuse treatment, 48(1), 96-103. https://doi.org/10.1016/j.jsat.2014.07.014
13 Volkow, N. D., Wang, G. J., Telang, F., Fowler, J. S., Alexoff, D., Logan, J., Jayne, M., Wong, C., & Tomasi, D. (2014). Decreased dopamine brain reactivity in marijuana abusers is associated with negative emotionality and addiction severity. Proceedings of the National Academy of Sciences of the United States of America, 111(30), E3149–E3156. https://doi.org/10.1073/pnas.1411228111
14 Balazs, J., & Kereszteny, A. (2017). Attention-deficit/hyperactivity disorder and suicide: A systematic review. World journal of psychiatry, 7(1), 44–59. https://doi.org/10.5498/wjp.v7.i1.44
15 Mitchell, J. T. et. al. (2016). “I Use Weed for My ADHD”: A Qualitative Analysis of Online Forum Discussions on Cannabis Use and ADHD. PloS one, 11(5), e0156614. https://doi.org/10.1371/journal.pone.0156614
16 Chauchard, E. et. al. (2018). Cannabis Withdrawal in Adults With Attention-Deficit/Hyperactivity Disorder. Prim Care Companion CNS Disord. 20(1). pii: 17m02203. doi: 10.4088/PCC.17m02203.
Cannabis use disorder uniquely affects people with ADHD. Learn about how marijuana impacts the ADD brain and the risks of abuse.
Can Marijuana Treat ADHD?
Marijuana is sometimes used as a self-treatment by individuals with attention deficit hyperactivity disorder (ADHD).
Advocates for marijuana as an ADHD treatment say the drug can help people with the disorder handle some of the more severe symptoms. These include agitation, irritability, and lack of restraint.
They also say that marijuana has fewer side effects than traditional ADHD medications.
Read more about what research has discovered about the use of marijuana in individuals with ADHD.
Laws and research
Marijuana remains illegal at the federal level. Each year, more U.S. states have passed laws allowing the sale of marijuana for medical purposes. Some states have legalized it for recreational purposes, too. Many states still outlaw any use of marijuana. At the same time, research into the effects of the drug on health conditions and diseases has increased. This includes research on marijuana use in individuals who’ve been diagnosed with ADHD.
Online health forums are filled with comments from people saying they use marijuana to treat symptoms of ADHD.
Likewise, individuals who identify as having ADHD say they have few or no additional issues with marijuana use. But they aren’t presenting the research on adolescent use of marijuana. There are concerns for the developing brain’s learning and memory.
“Many adolescents and adults with ADHD are convinced that cannabis does help them and has fewer side effects [than ADHD medications],” says Jack McCue, MD, FACP, an author, physician, and emeritus professor of medicine at the University of California, San Francisco. “It may be that they, not their doctors, are correct.”
Dr. McCue says he’s seen patients who report classic marijuana use effects and benefits. They report intoxication (or being “high”), appetite stimulation, help with sleeping or anxiety, and pain relief, for example.
Dr. McCue says these people sometimes report effects that are often seen with typical ADHD treatments, too.
“The limited research on what patients say cannabis does for ADHD symptoms indicates that it is most helpful for hyperactivity and impulsivity. It may be less helpful for inattentiveness,” Dr. McCue says.
Research in 2016 analyzed some of these online threads or forums. Of the 286 threads the researchers reviewed, 25 percent of posts were from individuals who reported that cannabis use was therapeutic.
Only 8 percent of posts reported negative effects, 5 percent found both benefits and harmful effects, and 2 percent said using marijuana had no effect on their symptoms.
It’s important to remember that these forums and comments aren’t clinically significant. They’re also not evidence-based research. That means they shouldn’t be taken as medical advice. Talk with your doctor first.
“There are descriptive accounts and demographic surveys that report that individuals with ADHD describe marijuana as being helpful in managing inattentiveness, hyperactivity, and impulsivity,” says Elizabeth Evans, MD, psychiatrist and assistant professor of psychiatry at Columbia University Medical Center.
However, Dr. Evans adds, “while there certainly may be individuals who experience benefit in their symptoms of ADHD, or those who are not adversely impacted by marijuana, there is not sufficient evidence that marijuana is a safe or effective substance to treat ADHD.”
Cannabidiol (CBD) is also promoted as a helpful treatment for individuals with ADHD.
CBD is found in marijuana and hemp. Unlike marijuana, CBD doesn’t contain the psychoactive element tetrahydrocannabinol (THC). That means CBD doesn’t produce a “high” the way marijuana does.
CBD is promoted by some as a possible treatment for ADHD. Dr. McCue says that’s because of “anti-anxiety, antipsychotic effects of CBD.”
However, “the lack of a potential paradoxical benefit from the stimulating effects of THC make CBD theoretically less attractive,” he says.
Dr. Evans adds, “There are no large-scale clinical trials looking at CBD for ADHD. It is not considered an evidence-based treatment for ADHD at this time.”
Some people with ADHD report that they find therapeutic benefit from using marijuana. Despite these anecdotal stories, research doesn't support marijuana, or CBD, as a treatment for ADHD. Who's right?