Comprehensive review reveals complex relationship between medicinal cannabis and ADHD
Findings from By Dr. Bryce Joynson
Read time: 4-5 mins
Comprehensive review reveals complex relationship between medicinal cannabis and attention deficit hyperactivity disorder, highlighting potential therapeutic mechanisms.
A comprehensive analysis of medicinal cannabis research developed by Dr. Bryce Joynson, MBBS/FRACGP revealed promising insights into how cannabinoids may help address key neurological features associated with attention deficit hyperactivity disorder (ADHD), particularly targeting overactive brain networks that contribute to symptoms like anxiety, difficulty concentrating, and emotional dysregulation.
The analysis, presented at the Australian and New Zealand College of Cannabis and Cannabinoid Practitioners (ANZCCP) Conference in May 2025, synthesised current research on the intersection between cannabis therapeutics and ADHD neurobiology. Dr. Bryce Joynson, MBBS/FRACGP, outlined how specific cannabinoids may modulate the Default Mode Network (DMN) - a brain network that becomes problematically overactive in ADHD patients.
Understanding ADHD's Neurological Landscape
ADHD affects up to 10% of children and an estimated 5% of adults, making it the most common mental health disorder affecting children. The condition involves complex neurochemical imbalances, particularly affecting dopamine and noradrenaline systems that regulate attention, motivation, and executive function.
Key ADHD Statistics highlighted within the presentation included:
Up to 84% of ADHD patients have one or more comorbid mental health conditions
60% have two or more comorbid conditions including anxiety, depression, and substance use disorders
50% of patients with severe obesity (BMI >40) have an ADHD diagnosis
Cannabis use is three times more likely among people with ADHD compared to neurotypical individuals
The Default Mode Network Connection
The research review identified overactive Default Mode Network activity as a crucial factor in ADHD symptomatology. The DMN, which includes the medial prefrontal cortex and posterior cingulate cortex, normally quiets during focused tasks but remains inappropriately active in ADHD patients.
"An overactive Default Mode Network is considered a key neurological feature associated with ADHD, where the DMN remains active even during tasks requiring focused attention, leading to difficulties concentrating and frequent mind wandering," Dr. Joynson explained in the presentation.
This overactivity contributes to several problematic symptoms:
Increased anxiety and obsessive-compulsive behaviors
Difficulty concentrating and task-switching
Heightened pain sensitivity
Emotional dysregulation and rumination
Sleep disturbances and fragmented REM sleep
Cannabis Compounds Show DMN Modulation Properties
Research indicates that THC (tetrahydrocannabinol) can modulate overactive DMN pathways in both schizophrenia and ADHD patients, as demonstrated through functional MRI studies. A 2013 study published in PLoS One found that THC could influence DMN activity during executive function tasks.
Additionally, cannabigerol (CBG), a lesser-known cannabinoid, has shown particular promise. A July 2024 double-blind, placebo-controlled study published in Scientific Reports found that CBG significantly reduced anxiety and stress while enhancing verbal memory, with no evidence of impairment or subjective drug effects.
"CBG may represent a novel option to reduce stress and anxiety in healthy adults," the researchers concluded, noting the compound's unique receptor profile that includes alpha-2 adrenergic activity and GABA modulation.
Patient Perspectives and Usage Patterns
The review noted significant real-world usage patterns that suggest patients are finding symptomatic relief:
More than 50% of daily cannabis users have ADHD
25% of ADHD forum participants believe cannabis is therapeutic for their condition
Up to 46% of patients seeking Cannabis Use Disorder treatment had ADHD diagnoses
Patient reports specifically mentioned CBG providing benefits similar to stimulant medications but "without the jittery/anxious feeling" and helping with emotional dysregulation and sleep quality.
Important Limitations and Concerns
The research review emphasised significant concerns about cannabis use in ADHD populations, particularly regarding THC. Studies show that individuals with ADHD who use cannabis may have blunted responses to conventional stimulant medications like methylphenidate.
Additional concerns include:
Potential for cannabis dependence (9% general population, 17% when started in adolescence)
Cognitive impairment, particularly in users under 25
Reduced motivation and executive function with chronic use
Recent increases in cannabis-induced psychosis cases
Clinical Implications and Future Directions
The research suggests that while cannabis compounds may offer therapeutic potential for specific ADHD-related symptoms, particularly anxiety and inflammatory conditions, careful consideration of individual patient factors is essential.
"If cannabis is working, why? What is it helping with?" Dr. Joynson emphasised the importance of understanding the specific mechanisms rather than treating cannabis as a general ADHD therapy.
The research underscores the need for individualised treatment approaches that consider the complex interplay between ADHD neurobiology, comorbid conditions, and potential therapeutic mechanisms of different cannabis compounds.
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.
