Difficulty paying attention, impulsivity, restlessness. These are all common symptoms among individuals with ADHD. Beyond these symptoms, those with ADHD also often struggle with other issues such as insomnia, anxiety, and depression. Because cannabis seems to alleviate many of the symptoms and issues that go along with ADHD, a few physicians recommend cannabis to their ADHD patients. More often, however, individuals will use cannabis to “self-medicate” their ADHD
Santa Barbara physician, Dr. David Bearman, is one physician who believe cannabis is not only an effective treatment for ADHD, it is a safer alternative to many prescription medications. However, cannabis as an ADHD treatment, is controversial. Very few researchers have studied cannabis as an ADHD treatment. And, because there’s evidence that suggests individuals with ADHD are at higher risk of developing a substance use-disorder (SUD) — not just for cannabis, but other drugs — most of the research has been limited to examining potential links between ADHD and cannabis dependency.
Nonetheless, questions persist: Could cannabis be an effective ADHD treatment? Could our developing knowledge of the body’s own cannabinoid system — the endocannabinoid system, or ECS — provide some answers into the causes of ADHD, while opening up avenues to develop new medications? These are important questions that we’ll explore in this article. But first, let’s begin with what we know about ADHD.
What is ADHD?
According to the National Institute on Mental Health, Attention-deficit/hyperactivity disorder, more commonly called ADHD, is “a brain disorder marked by an ongoing pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development.”
The disorder is characterized by the following:
- Inattentiveness: Difficulty paying attention or taking instructions; wandering off task; difficulty staying organized and sustaining focus.
- Impulsivity: Acting out without thinking through consequences; seeking immediate rewards while unable to delay gratification. Impulsivity may lead to social awkwardness like intruding on conversations.
- Hyperactivity: Fidgeting; difficulty remaining still or sitting in a seat; extreme restlessness.
The dominance of these symptoms varies by individual, and tend to vary according to ADHD subtype. According to American Psychiatric Association’s diagnostic “bible,” the DSM-V, there are three categories of ADHD:
- Predominantly inattentive presentation
- Predominantly hyperactive-impulsive presentation
- Combined presentation
Subtypes of ADHD have been a source of controversy with many researchers criticizing them as not reliable. One study from the Department of Psychiatry, University of Chicago, re-assessed children seven times over eight years, and found that a high percentage of them were later diagnosed with a different subtype in two or more assessments. And, in fact, the DSM-5 dropped the term “subtype,” in favor of “presentation.”
How Common Is ADHD?
According to the American Psychiatric Association, 5% of children have ADHD. However, some studies have recently put the figure as high as 10% (or more). The reason for the higher figures is unclear. Is ADHD increasing among children? Or, is an increased awareness leading to more diagnoses? Or, are aggressive “Big Pharma” companies encouraging the overdiagnosis of ADHD? Rates appear to decrease with age, but studies have shown that 80% of children diagnosed with ADHD continue to suffer from symptoms as adults.
What Causes ADHD?
Evidence suggests dysregulation of dopamine and norepinephrine neurotransmitters are responsible for ADHD. Dopamine plays a key role in attention and short-term memory. A deficiency in dopamine may also promote immediate gratification while delayed reinforcement is less effective. Hence, explaining impulsivity and hyperactivity.
But, what causes dysregulation of these neurotransmitters in the first place? The precise cause remains a mystery, although a number of factors appear to play a role:
There appears to be a strong genetic component, as children who have a parent with ADHD have a 50% chance of also having it. Similarly, 30% children with an older brother or sister that has ADHD, also have it.
Issues During Pregnancy:
Children born with a low birth weight, born premature, or whose mothers had difficult pregnancies, are at higher risk of having ADHD. The same is true for children with head injuries to the frontal lobe of the brain, the area that controls impulses and emotions. Studies show that pregnant women who smoke or drink alcohol may have a higher risk of having a child with ADHD. Some researchers speculate that exposure to lead, PCBs, or pesticides could also have a role.
Could the Endocannabinoid System Play a Role in ADHD?
The body has its own cannabinoid system — called the endocannabinoid system, or ECS. Arguably, it’s the body’s most important physiological system, as it plays a vital role in virtually every aspect of our health. Further, it has been suggested that because the ECS influences catecholaminergic transmission — catecholamines are neurotransmitters, dopamine, epinephrine, and norepinephrine — and, the malfunctioning of the catecholaminergic systems is a plausible cause of ADHD, deficiencies or imbalances in the ECS could be to blame for ADHD.
One study published in Neuroscience and Behavioral Reviews found that activating the CB1 receptor (in experimental animal models — aka “lab rats”) normalized behavior, while producing a neutral effect on non-ADHD rats. (Rats with ADHD? These are experimental genetically “designed” rats whose brains mirror ADHD symptoms.)
Research on animal models doesn’t always translate neatly to human subjects, but this early research is important. First, it offers a potential explanation behind ADHD. Lower CB1 receptor density appears to be significantly lower in “impulsive” rats. Could cannabinoids — in this case WIN 55.212 — correct this deficiency? Moreover, THC and other cannabinoids, produce their brain-related effects by activating the CB1 receptor. The researchers believe they’ve come across an important lead:
[These] results support the notion that a reduced cortical density of cannabinoid CB1 receptors is associated with enhanced impulsivity. This behavioral trait can be positively modulated by administration of a cannabinoid agonist.
The researchers experimental model suggests a viable model for further preclinical investigation into early-onset ADHD syndrome, and further exploration of the potential to develop cannabinoid-derived treatments.
Another study found that elevating endocannabinoids during pregnancy can correct the unbalance between dopamine systems, thereby reducing hyperactivity. Researchers note that because alterations in the brain’s “reward pathway” (the mesocorticolimbic system) appear to influence hyperactivity and attention deficit, this could be corrected by elevating levels of anandamide — the body’s naturally occurring version of THC — during pregnancy. Does this mean pregnant women should take cannabis supplements during pregnancy? No. (There’s also evidence suggesting that women who smoke cannabis during pregnancy are more likely to have children with ADHD). But, it adds to evidence that an endocannabinoid deficiency could be to blame for ADHD. Through further research we could potentially develop novel treatments for ADHD. The authors conclude:
“The data suggest a corrected unbalance between the two dopamine systems that apparently leads to reduced hyperactivity and modified scanning times in this animal model of ADHD. This, in turn, might open new strategies in the treatment of a subset of ADHD cases.”
Common Treatments for ADHD
The most common treatments for ADHD are as follows:
- Stimulants: The most common first line treatments include stimulants — like Adderall and Ritalin — both of which influence dopamine transmission. Studies have shown that these drugs improve performance related to executive functioning, memory and impulsivity, while controlling other symptoms. Modafinil, a non-scheduled / non-controlled stimulant has demonstrated efficacy comparable to drugs like Adderall and Ritalin. However, as many as 30% of patients don’t respond favorably to stimulants.
- Antidepressants: Wellbutrin (bupropion) seems to be one of the most effective antidepressants in treating ADHD, which makes sense as it beneficially influences dopamine and norepinephrine regulation.
- Beta-blockers: Propranolol, nadolol, and pindolol have demonstrated efficacy in controlling aggression, angry outbursts, and behavioral issues. They may also alleviate anxiety and impulsiveness.
A comprehensive review — albeit ten years old — of non-stimulant ADHD treatments was published in the peer-reviewed Journal of Psychiatry and can be viewed on PubMed.
Is Cannabis Consumption Helpful (or Harmful) for ADHD?
Because the endocannabinoid system influences transmission of catecholaminergic neurotransmitters, it’s certainly plausible that manipulating these pathways with cannabinoids could positively (or negatively) affect ADHD. However, there haven’t been any rigorous high-quality human studies of cannabis (or cannabinoids) in the treatment or management of ADHD symptoms.
Until recently, most research on cannabis — with the notable exception of a few areas such as cancer, neuropathic pain, etc. — has focused on proving negative assumptions about cannabis. Few areas has this been more true than research involving ADHD, particularly given evidence suggesting those with ADHD are at a higher risk of developing a substance use-disorder than the general population.
One study suggests that between 34% and 46% of adults seeking treatment for cannabis use disorders have ADHD. A criticism of some of the research has been that investigators leading the studies often don’t consider the fact many cannabis users who would meet the clinical definition of having a use disorder, present symptoms consistent with ADHD during chronic problematic cannabis use, yet after a month or longer of abstinence from cannabis, would no longer meet the criteria for an ADHD diagnosis. Logically, if the diagnosis of ADHD is overrepresented, so is the data.
Another criticism is that studies don’t often consider if a subject is using cannabis to (responsibly) self-medicate. Their use — while frequent, as if they were taking a prescribed medication — may not constitute a use-disorder. Anecdotally, many ADHD users report using cannabis to treat manage ADHD symptoms.
Take the example of Matt Riddle, ADHD sufferer and former UFC welterweight disqualified for testing positive for cannabis (despite possessing a state-sanctioned medical marijuana physician recommendation):
“In 3rd grade they gave me Ritalin, which is basically speed. It slows you down if you're a little hyper to begin with. It made me a zombie. It made me sit there and focus. I ended up getting better grades, but at what cost? I stopped taking it in my sophomore year. The medication was eating away at my stomach; I was getting ulcers in my esophagus. I was smoking weed at that point, and my parents knew -- they saw that I was calm and collected. They told me: ‘Matt, you can smoke weed, and you don't have to take Ritalin anymore. You can do your own thing.’ … I wish I could have used a form of medical marijuana when I was in 3rd grade."
A group of researchers in Germany suggest some individuals with ADHD can benefit from cannabis. They compiled a case report documenting a 28-year old male who presented maladjusted and inattentive behaviors without cannabis, but whose behaviors significantly improved after using cannabis. Interestingly, the subject was also able to drive more safely — an unexpected and atypical outcome!
Treating ADHD, however, with cannabis can be tricky. It seems to work for some people, but not for others, and because controlled studies are non-existent, there are no credible statistics on what percentage of ADHD sufferers respond favorably. Kayvan Khalatbari, co-founder of Denver Relief Consulting and ADHD sufferer explains: "As to whether it works for helping to treat ADHD...there are so many variables at play and it may [work] for some, but not for others. There are also so many different cannabinoid profiles at play that we just don't know yet. [But] for me personally, yes, it has helped."
Anecdotes can be valuable and definitely shouldn’t be dismissed, as they serve as valid pointers for researchers to investigate further. However, as Khalatbari points out, there are numerous variables at play, and with anecdotal reports, it’s impossible to generalize efficacy across large populations of sufferers. For example:
- What percentage of patients respond favorably to cannabis treatment? We have no idea if it’s 75%, 25% or 5%. We generally only hear about the success stories. How often do people go around telling everyone that cannabis didn’t help them? Few people want to be “Debbie Downer,” particularly if there are others who’ve been helped.
- How much of the positive effects can be attributed to a placebo effect (an effect attributed to belief, but not supported by objective measures)?
- How does cannabis compare (in terms of effectiveness and risks) to other well-studied medications (e.g. Adderall, Ritalin, Concerta, etc.)?
What about CBD?
CBD, the second most prominent constituent in cannabis, has generated a lot of buzz for providing tremendous therapeutic versatility, while not producing psychotropic effects. Studies have demonstrated CBD may be effective at treating a wide range of symptoms, some of which are commonly present in ADHD such as anxiety and impulsivity. Moreover, unlike THC (and most drugs), CBD appears to exert virtually no adverse or undesirable side effects.
Depressingly, despite CBD’s remarkable therapeutic versatility and safety profile, high-quality research on CBD as a treatment for ADHD is essentially non-existent. One encouraging study, however, on experimental animal models found cannabidiol (CBD) alleviated two common complaints among ADHD sufferers: hyperactivity and social withdrawal. However, there were no reported effects on attention span.
Another compelling reason to prioritize CBD research is that notable evidence has emerged suggesting CBD is being helpful in treating addictive behaviors. Researchers at the Laboratory of the Biology of Addictive Diseases, The Rockefeller University, proposed a predictive model of addiction that examined genetic influences — specifically, impulsivity, risk taking, and stress responsivity — on drug misuse vulnerability. These characteristics are all common among ADHD sufferers, and if CBD can help lessen their influence, CBD could prove invaluable in helping individuals with ADHD lower their risk of developing a substance use-disorder (or treat an existing one).
Given the promise of CBD as an effective agent in treating addictions — and quite possibly helping patients temper characteristics that put them at risk in the first place — CBD could open up new treatment pathways for a population that could benefit immensely. Likewise, further research could answer some important questions. To start, if patients choose cannabis with higher CBD levels, could that reduce their risk of developing a dependency on cannabis — or other substances, for that matter?
Research on cannabis to treat ADHD is still in its infancy. However, a few physicians have been convinced by the early data, scientific plausibility and their own observations, that cannabis can be an effective ADHD treatment. However, it’s not clear why it works for some patients and not others, nor do we even know how likely it is that a patient will respond favorably. Moreover, given the fact that individuals with ADHD are more likely to misuse drugs — not just cannabis — it’s important to consider the risks before deciding to use cannabis therapeutically.