The Medical Use of Cannabis to Treat ADHD - an Australian Case Study
Article Written By Dr. Bryce Joynson
The use of medicinal cannabis for the treatment of ADHD (attention deficit hyperactivity disorder) is becoming increasingly popular since its legalisation and increased access in Australia.
Understanding ADHD
ADHD is a neurodevelopmental disorder that significantly impacts the brain's executive functions. The hallmark of ADHD is proposed to be an underproduction and lack of dopamine in the brain’s frontal lobes, which control symptoms such as:
Emotional regulation
Impulse control
Short-term memory
Focus and concentration
Procrastination
Many other executive domains
Benefits of Medicinal Cannabis for ADHD
Cannabis has actions on the frontal lobe, increasing the release of dopamine (DA) and noradrenaline (NA), which many patients with ADHD find very beneficial. Additionally, cannabis can help regulate or disrupt the default mode network (DMN), a hallmark of ADHD that causes the "busy brain" many patients describe. Patients report that THC appears to calm their brains down and allow them to focus, relax, or get to sleep.
Precautions and Potential Pitfalls
While CBD can be neuroprotective and help regulate neurotransmitters, the use of high-dose THC can cause blunting of the dopamine and adrenaline receptors, which will worsen ADHD symptoms. It can also lead to dependence issues and a permanent reduction in IQ in younger adults <25. Prescribers need to be acutely aware of the interaction between cannabis therapies and ADHD medications, including psychostimulants (Dexamphetamine, Vyvanse, and Ritalin). Close consideration and collaboration with the prescribing doctor or psychiatrist should be sought before adding any THC-based treatment to a person using psychostimulant medication.
Oral vs. Inhaled Cannabinoid Therapies
It is essential to understand the difference between oral and inhaled cannabinoid therapies. My preference is always to use an oral-based cannabinoid therapy over inhaled THC. Oral therapies benefit from slow metabolic uptake and gradual receptor augmentation, while inhaled therapies have a quick onset of action but a higher chance of over-activating the receptors.
Figure 1: Chart showing the onset of effects of oral vs inhaled THC.
Case Study
To illustrate the potential benefits and challenges of using medicinal cannabis for ADHD, let's take a look at a case study.
Patient Background
50-year-old male
Presents with severe depression, anxiety, relationship issues, and suicidal ideation.
Diagnosed with ADHD, PTSD, and chronic pain issues.
Not working, struggling with pain, sleep, and borderline suicidal ideation.
Recreationally using up to 28g of cannabis per week.
Smoking nicotine 20+ cigarettes daily.
Prescribed 18x 5mg dexamphetamine by his GP and Palexia 100mg twice daily, Mirtazapine 30mg twice daily.
Initial Treatment Plan
Discussed goals of cannabis therapy
Started with the addition of oral Entoura CBD200 Full spectrum oil 0.5ml daily
up to 2g of Cannatrek Argamon balanced CBD/THC (7%THC, 9%CBD) inhaled flower was added per day.
Sent for blood tests and resting Brain Spectral CT scan.
Figure 2: Brain Spectral CT scan showing Increased activity in the Posterior occipital cortex (a) and Middle Frontal Gyrus (b)—a common finding in patients with an overactive Default mode network.
Treatment Adjustments
Changed Flower to Rainbow Sunset Indica 20% flower 1g daily, continued CBD oil.
Added 20mg oral THC pastille (compounded product) before bed.
Added Clonidine 100 micrograms in the evening to aid sleep initiation.
Lamotrigine was added at 25 mg BD and increased to 50mg BD.
Added Zyban150mg in the morning for DA and NA reuptake to help with smoking cessation/ADHD daytime symptoms.
Regular exercise, change in diet, 1000mg of L-Tyrosine, and ice baths are recommended.
Patient had reduced to 2 dexamphetamine per day
3-Month Review
Patient feels calmer and regulated.
Pain is significantly more manageable. And has stopped Palexia completely.
No longer drinks alcohol or smokes cigarettes.
Works 20 hours per week and apply for a full-time job.
Improved relationships at home and better emotional regulation
Purchased a vaporiser instead of using a bong and adjusting temperature settings.
Changed to a combination of hybrid strains Alfie MAC-1 22% for daytime use and Rainbow Sunset indica 20% in evenings to optimise terpenes and manage anxiety/stress.
Goals are to reduce THC further to maintain symptom control using <1g daily.
Debate and Future Research
There is much debate in the cannabis community about whether Sativa-dominant, Hybrid, or Indica-dominant strains are better for ADHD symptom management. Due to the complexity of ADHD and the varying subtypes and co-morbid factors, it requires an experienced clinician to determine the most suitable product for the patient.
There is also much debate around the need for increasing the strength of cannabis therapies. Often, patients with ADHD will improve with a lower dose of THC due to the biphasic and receptor-blunting effect of higher doses. It is also essential to always consider adding CBD to provide neurocognitive protection from THC.
This is a very new field with much research to be done. Many patients are seeking out cannabis as an alternative ADHD treatment for its benefits on anxiety and insomnia, which are common comorbidities. Patients who are finding it difficult to get appropriate support from their regular doctor may turn to cannabis as a self-medication strategy or look to medicinal cannabis for support with their symptoms.
Conclusion
For clinicians prescribing cannabis for anxiety/insomnia, I encourage you to screen the patient for ADHD and consider this in your management when choosing cannabinoid medicines. There is much clinical debate about whether cannabis is an appropriate treatment for ADHD, and much more research needs to be done in this area by experienced clinicians due to the multifactorial nature of this condition.
Recommendations:
Always encourage the use of CBD in treatment
Consider a combination of oral vs. inhaled therapies.
Use the lowest dose of THC possible.
Avoid combining Cannabis and ADHD medications unless this has been discussed with their regular prescriber due to the high risk of interactions.
If you'd like to learn more about ADHD and cannabis, please listen to my podcast on this topic. I hope that, as a community, we can further our understanding of this complex condition and improve the lives of our patients through responsible and evidence-based use of medicinal cannabis.
Dr. Bryce is a neuro-affirming Specialist General Practitioner with extensive training in the assessment and management of Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactive Disorder (ADHD). Dr. Bryce provides lectures, podcasts, and training in this field and is at the forefront of current advancements in treatment techniques, including cannabis medicine.
Dr. Bryce has developed his Brain Spectral CT scanning protocol based on the work of Dr. Daniel Amen to use neuroimaging for assistance with the diagnosis and management of mental health disorders, including ASD/ADHD.
Dr. Bryce is also registered as one of Australia’s first General Practitioners to acquire pediatric Authorised prescriber status for medicinal cannabis. His experience and knowledge in this field have been recognised by the Therapeutic Goods Administration (TGA) and the National Institute of Integrative Medicine (NIIM), which allows him to provide highly specialized care to his pediatric patients who require medicinal cannabis therapies.
Disclaimer: This information is shared with a global readership for educational purposes only and does not constitute medical or business advice. All patient-related information has been de-identified OR fictional to protect privacy. Nothing in this article is intended to promote the use or supply of medical cannabis to members of the public.
