CBD and ADHD: What Does the Human Research Show?
CBD is frequently discussed online by people with attention deficit hyperactivity disorder (ADHD), particularly in relation to concentration, restlessness, sleep and feeling overwhelmed.
But personal experiences and biological theories are not the same as evidence that CBD treats ADHD.
At present, human research does not establish CBD as a treatment for ADHD or demonstrate that ordinary CBD isolate improves attention, impulsivity, hyperactivity or executive function. The controlled clinical evidence is extremely limited, and an important distinction is often missed: the main randomised trial involved a medicine containing both THC and CBD, rather than CBD alone.
This guide looks at what researchers have actually studied, what they found and what people in the UK should know before interpreting those results.
What is ADHD?
ADHD is a neurodevelopmental condition affecting areas such as attention, organisation, impulse control and activity levels.
Adults with ADHD may experience difficulty concentrating, organising tasks, completing activities, controlling impulses or managing restlessness. Symptoms and their impact vary considerably between individuals. The NHS guide to ADHD in adults provides further information.
ADHD should not be reduced simply to having a “busy mind” or finding it difficult to concentrate occasionally. NICE states that diagnosis should be made by an appropriately qualified healthcare professional following a full clinical and psychosocial assessment. See the NICE ADHD recommendations.
Has CBD been tested in people with ADHD?
There is very little controlled human research.
One frequently cited study was a small six-week randomised, double-blind, placebo-controlled trial involving 30 adults with ADHD.
Researchers tested Sativex, also known as nabiximols. Importantly, this was not a CBD-isolate product. It was a cannabinoid medicine containing approximately a 1:1 ratio of THC to CBD.
The study's primary outcome looked at cognitive performance and activity levels using a QbTest. Researchers found no statistically significant difference on the primary outcome between the cannabinoid medicine and placebo. The trial is available on PubMed.
There were apparent improvements on some secondary measures, including hyperactivity and impulsivity, but these findings were preliminary and did not remain statistically significant after adjustment for multiple comparisons.
That makes the trial an interesting early study, but it is not evidence that CBD itself treats ADHD.
Why the THC and CBD distinction matters
This is one of the most important limitations when discussing the research.
A clinical trial of a medicine containing THC and CBD together cannot tell us what CBD isolate would do on its own.
THC and CBD are different cannabinoids with different pharmacological effects. It would therefore be inappropriate to take results from the Sativex trial and use them to claim that a retail CBD-isolate oil improves ADHD symptoms.
Valley CBD oils are formulated using CBD isolate rather than a THC/CBD medicinal formulation, so the two should not be treated as equivalent.
What do larger research reviews conclude?
A 2023 scoping review examined 39 studies concerning cannabis and ADHD. Only one study in the review was a randomised placebo-controlled trial directly investigating cannabinoids for ADHD: the 30-person study described above.
The reviewers found that most of the available literature was observational rather than experimental. THC and CBD exposure was also often poorly measured. Although some studies reported improvement, the majority found either worsening of ADHD symptoms or no effect.
The review concluded that the available evidence was insufficient to recommend cannabis for people with ADHD. It also highlighted that the isolated effects of CBD itself were not well established. The review is available on PubMed.
A further 2024 review examined ADHD, cannabis and the endocannabinoid system. Researchers found biological questions worth investigating but emphasised that the relationship between cannabis use and ADHD symptoms remains poorly understood and that considerably more research is needed. See the 2024 review on PubMed.
That is very different from demonstrating that CBD is an effective ADHD treatment.
What about the endocannabinoid system?
The endocannabinoid system, or ECS, is involved in numerous biological processes, and researchers are investigating whether differences in endocannabinoid signalling may be relevant to ADHD.
This makes the ECS scientifically interesting, but a plausible biological mechanism does not establish clinical effectiveness.
Researchers can identify receptors, signalling pathways or biological associations without demonstrating that taking a particular substance improves a medical condition. The 2024 review describes the ECS as an area for further ADHD research rather than an established treatment target.
Does CBD improve concentration or executive function?
There is currently insufficient clinical evidence to say that retail CBD improves concentration or executive function in people with ADHD.
This distinction matters because terms such as “focus”, “mental clarity” and “productivity” can easily turn an uncertain research hypothesis into what sounds like a proven benefit.
The controlled ADHD study did not demonstrate a significant improvement in its primary objective measure of cognitive performance and activity. Furthermore, because the treatment contained THC as well as CBD, it cannot establish an effect for CBD isolate.
Claims that CBD “filters out mental noise”, provides “clean focus” or improves executive function therefore go beyond the available evidence.
Does CBD reduce ADHD hyperactivity or restlessness?
Again, the evidence is insufficient.
The small Sativex trial reported preliminary signals on a secondary hyperactivity/impulsivity measure, but those findings did not remain statistically significant after adjustment for multiple comparisons.
It would therefore be misleading to turn that result into a claim that CBD reduces ADHD hyperactivity. Larger, CBD-specific controlled trials would be needed before drawing that conclusion.
What about anxiety alongside ADHD?
ADHD can occur alongside other mental health conditions, including anxiety.
Research into CBD and anxiety is a separate field and should not be used as indirect proof that CBD treats ADHD. Even if a study finds an effect in a particular anxiety disorder, that does not establish improved concentration, executive function or impulsivity in ADHD.
We examine that evidence separately in our guide to CBD and anxiety research.
Is stronger CBD more effective for ADHD?
There is no evidence that a higher-strength retail CBD oil is more effective for ADHD.
Bottle concentration tells you how much CBD is present in a given quantity of oil. It does not tell you that the product will be more effective for a particular medical condition.
The ADHD research does not provide evidence for recommending 10%, 20%, 30% or 40% CBD oil according to ADHD symptoms. Research doses from clinical studies should also not be converted into consumer dosing recommendations.
Can CBD replace ADHD medication?
Current evidence does not support replacing established ADHD treatment with retail CBD.
For adults whose ADHD continues to cause significant impairment after environmental modifications have been reviewed, NICE recommends established treatments according to individual circumstances.
For adult pharmacological treatment, NICE currently recommends lisdexamfetamine or methylphenidate as first-line options. Structured psychological interventions, which may include elements of cognitive behavioural therapy, can also form part of ADHD management. See the NICE ADHD guideline.
The NHS similarly describes ADHD management as potentially involving lifestyle measures, adjustments at work or education, specialist-prescribed medicines and talking therapies.
CBD is not listed by NICE as an ADHD treatment. Anyone considering changing prescribed ADHD treatment should discuss this with their healthcare professional rather than replacing or stopping medication independently.
Can you take CBD with ADHD medication?
This requires particular caution.
The UK's Food Standards Agency currently advises that people taking medication should avoid CBD unless under medical direction because of uncertainty around interactions between CBD and medicines. See the FSA guidance on CBD safety and health claims.
That is more useful than trying to provide a general online answer for individual ADHD medicines because interaction risk can depend on the medicine, dose, other health conditions and other treatments being taken.
If you use methylphenidate, lisdexamfetamine, atomoxetine or another prescribed ADHD medicine and are considering CBD, speak to your doctor or pharmacist.
What does UK guidance say about CBD?
For CBD products sold as foods or food supplements, current FSA advice is that healthy adults should consume no more than 10mg of CBD per day.
The FSA also advises people under 18, people who are pregnant, breastfeeding or trying to conceive, and people taking medication to avoid CBD unless under medical direction.
Crucially, the FSA states that there are no authorised health claims for CBD foods and that claims that CBD foods treat illness or provide medical benefits are not permitted.
The MHRA separately states that CBD products marketed for medical purposes are medicines. A CBD product marketed using medicinal claims can therefore fall within medicines regulation. See the MHRA statement on products containing CBD.
This is why research about CBD can be discussed without presenting an ordinary retail CBD product as an ADHD treatment.
Frequently asked questions
Can CBD cure ADHD?
No evidence shows that CBD cures ADHD. Current human cannabinoid research is limited and does not establish CBD as an ADHD treatment.
Is CBD clinically proven to help ADHD?
No. The main randomised trial involved only 30 adults and tested a THC/CBD medicine rather than CBD alone. Its primary outcome was not significantly different from placebo.
Does CBD improve focus in ADHD?
There is currently insufficient controlled evidence demonstrating that CBD isolate improves attention or executive function in people with ADHD.
Does CBD calm ADHD hyperactivity?
The available research does not establish that CBD reduces ADHD hyperactivity. Preliminary findings from a small THC/CBD trial are insufficient to make that claim.
Is CBD safer than ADHD medication?
They cannot sensibly be compared in that way. Established ADHD medicines have specific evidence, indications, risks and monitoring requirements. Retail CBD is not an approved ADHD treatment.
Can I use CBD while taking ADHD medication?
The FSA currently advises people taking medication to avoid CBD unless under medical direction. Speak to your doctor or pharmacist before combining them.
The bottom line
There is genuine scientific interest in cannabinoids, the endocannabinoid system and ADHD.
But scientific interest is not the same as proof of treatment effectiveness.
Current research does not establish that CBD isolate treats ADHD, improves concentration, reduces impulsivity or hyperactivity, or enhances executive function.
The only small controlled adult trial tested a medicine containing both THC and CBD and failed to show a significant benefit on its primary outcome. Subsequent reviews continue to describe the evidence as limited and uncertain.
For people with diagnosed ADHD, established NHS and NICE pathways remain the appropriate basis for treatment decisions. CBD research may develop in future, and if stronger evidence appears, this guide can be updated accordingly.
This article is for general educational information and does not provide medical advice or recommend CBD for the treatment of ADHD.