Many cannabis patients with ADHD report that using cannabis helps with their ADHD symptoms, and the research suggests that it may be a beneficial treatment. There is a strong link between ADHD and dysregulation of the endocannabinoid system — which suggests that activating this system could lead to improvement for some ADHD patients.
In addition, case and clinical studies indicate that ADHD sufferers may have non-standard responses to cannabis. Instead of experiencing the common cognitive side effects associated with cannabis use (such as lack of focus, short term memory loss, and lack of coordination), ADHD sufferers may actually find these areas improved with cannabis use.
How cannabis affects ADHD
To understand how cannabis might be able to impact ADHD, we first need to understand how ADHD is impacted by the endocannabinoid system — the system in the human body that cannabis activates to provide its wide range of effects. This important system is tasked with maintaining homeostasis (or internal balance) for many bodily functions, such as sleep, pain, memory, inflammation, energy metabolism, hunger, mood and even focus.
Made up of three parts, this system contains naturally produced chemicals called endocannabinoids, endocannabinoid receptors (which the endocannabinoids bind with to activate the endocannabinoid system effects) and enzymes which metabolize the endocannabinoids and clear them from the body.
In healthy individuals this system works normally on its own — but disruptions to it can cause a variety of negative health effects. Interestingly, there are also chemicals in cannabis (called phytocannabinoids or cannabinoids for short) which interact with the endocannabinoid system in the same way our natural endocannabinoids do. These cannabinoids, such as THC and CBD, are very similar to the endocannabinoids produced in our own bodies and are also able to activate endocannabinoid receptors and thus cause a wide array of effects.
In ADHD patients, this natural endocannabinoid system may be dysregulated, causing issues with focus and impulsivity. There are a few pieces of evidence that point to this.
For one thing, in rodent studies, ADHD has been tied to misfirings of the endocannabinoid system — a system that is crucial for regulating focus. Abnormal dopamine transmission is a key aspect of ADHD, and this is actually modulated by the endocannabinoid system. In particular, studies show that the CB1 receptor is crucial to this type of dopamine signaling and so its modulation or activation (perhaps using cannabis) could theoretically have a big impact on symptoms of ADHD.
This connection between ADHD, the endocannabinoid system and CB1 is further supported by genetic research into ADHD. Studies show that genetic variants for the gene associated with the CB1 receptor are correlated with ADHD. Thus it is highly possible that ADHD is a genetically inherited dysregulation of the endocannabinoid system – and in particular the CB1 receptors.
Given this strong association between ADHD and the endocannabinoid system, there is good theoretical reason to believe that cannabis can impact ADHD. But at the same time, cannabis has a bad reputation for negatively impacting focus. In healthy individuals, acute cannabis use is likely to cause disruptions in focus. So historically, there has been some worry that cannabis use would actually worsen ADHD. Still, the evidence (while limited) points in the opposite direction. Rather than worsening ADHD, the science suggests that cannabis can actually improve ADHD symptoms.
The first clues for researchers that cannabis might help ADHD were case studies of individuals with ADHD who seemed to experience a relief of their symptoms after cannabis use. One compelling case study describes a 28-year old male who showed “improper behavior and appeared to be very maladjusted and inattentive while sober.” Surprisingly, researchers found that when this man used cannabis he became “completely inconspicuous” in his symptoms, seeming more focused and stable. His doctors compared his performance in a battery of tests designed to evaluate focus and attention (including driving tests). They found that he performed far better on these measures when he had very high blood plasma levels of THC, than he did without cannabis in his system. The researchers concluded that for some individuals with ADHD, rather than causing problems with focus, attention, and coordination, cannabis could actually lead to improved abilities in these areas.
Interestingly, other studies have shown similar results for patients with Tourette’s syndrome. Rather than having the normal cognitive response to acute cannabis use, these patients suffered from no cognitive deficits when using cannabis. Tourette’s syndrome is also associated with the dopaminergic system, so it makes sense.
Still, case studies are tricky to evaluate because it’s hard to control for outside factors, such as the use of other drugs, unknown health conditions, or just about anything else that isn’t tracked by your doctor but might impact your situation. While it’s clear from this that one individual’s focus was positively impacted by cannabis – it’s not clear from this whether it is a trend for ADHD in general. But luckily the science doesn’t stop here.
Other scientists took this to the next step and put together a placebo-controlled study to look at the phenomena of ADHD patients self-medicating with cannabis to determine whether cannabis actually improved ADHD symptoms, in comparison to a placebo. In this study, which included 30 adults with ADHD, researchers gave half the subjects Sativex Oromucosal Spray (a cannabinoid-based medication) and the other half a placebo. Then they evaluated their cognitive performance, activity levels, and ADHD symptoms. While the results didn’t meet statistical significance for cognitive performance or activity levels, cannabis users tended to score higher on these measures than the placebo group — suggesting that (at the very least) cannabis didn’t seem to cause the cognitive deficits and sedative effects usually seen in acute cannabis use for these ADHD patients. In addition, when it came to the ADHD symptoms, the cannabis-using group outperformed the control group, showing improvement in scores for hyperactivity/impulsivity, inhibition, and inattention. Still, these results were not statistically significant after the full analysis was complete so more research is needed to confirm or disconfirm these results. Nonetheless, researchers in this study reported that it suggests “adults with ADHD may represent a subgroup of individuals who experience a reduction of symptoms and no cognitive impairments following cannabinoid use.”
In addition to this study on ADHD and cannabis, another study looked at cannabis use in ADHD patients who were seeking treatment for cocaine addiction. Researchers studied 92 cocaine dependant ADHD patients in a clinical trial for methylphenidate (a drug used to treat ADHD) in an outpatient setting. Sixty-nine percent of those patients were using cannabis as well during their treatment. The analysis found that moderate cannabis users actually had improved retention rates in the program. Parallel to that, cannabis has shown very promising evidence on helping treat addiction.
We also see some evidence from animal studies. One study looked at hyperactivity in rats, using a nose-poking test where rats had two holes in their cage that they could poke with their nose to get a food reward. For one hole, the food was delivered immediately but in a small amount. For the other hole, the food was delayed but was a larger amount, which got progressively larger each time. The less impulsive rats were able to delay gratification and show preference for the delayed larger amount of food. Researchers found that stimulating CB1 receptors normalized impulsivity behavior in hyperactive rats, while having no effect on healthy control rats. This suggests that stimulating CB1 (such as with THC) can improve this aspect of ADHD.
The research, as a whole, does point to the possibility that cannabis could improve ADHD symptoms such as inattention, hyperactivity, impulsivity and addiction to other dopamine stimulants, for some. Still, the research is very limited with mostly small sample sizes, and positive results that are often not statistically significant. More large scale, controlled clinical research is needed before we can say for sure that cannabis can help with ADHD.
Potential side effects of cannabis use
Despite the positive potential for cannabis and ADHD, cannabis comes with a wide array of potential side effects — which can be a deterrent for some. Cannabis use may cause effects like temporary cognitive deficits, short term memory loss, focusing issues and impaired coordination — although these effects are less prevalent in patients with ADHD. It can also cause mood-related issues like anxiety, paranoia, or depression, and it may cause respiratory symptoms such as asthma, coughing and increased phlegm production when inhaled.
Cannabis can increase the risk of psychosis for schizophrenic patients, and it can also increase the risk of certain cardiac conditions. For a minority of patients, cannabis can also lead to addiction.
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