By Emily Ledger
Until recently, the link between attention-deficit/hyperactivity disorder (ADHD) and cannabis use has largely been seen through a negative lens, with studies largely focusing on the potential harms of cannabis use for young people using the drug.
However, recent years have brought a more nuanced approach to understanding why cannabis use is more prevalent among adolescents with ADHD.
What is Attention-Deficit/Hyperactivity Disorder?
ADHD is a kind of neurological condition which is characterised by inattention and hyperactivity. The condition most commonly begins in childhood, with symptoms often easing off or improving by adulthood. There are three subtypes of ADHD: primarily hyperactive-impulse type, primarily inattentive type (previously called ADD) and primarily combined type.
ADHD was only recognised as a valid condition in the UK in 2000, however, it was still not officially recognised as an adult condition until 2008. According to the NHS, around 3-5% of children in the UK may have some form of ADHD, reducing to 2% of UK adults.
Research has shown that people with ADHD are more likely to use drugs and commit crime, with a shocking 30% of prisoners in the UK estimated to have some form of the condition. Furthermore, adults with ADHD are more than twice as likely to meet the criteria for cannabis use disorder (CUD).
Once receiving a diagnosis of ADHD, an individual will typically be offered behavioural therapy and, depending on their age, medical treatment with pharmaceutical drugs such as Ritalin and Adderall – types of methylphenidate and amphetamine.
How do these pharmaceuticals work?
While these kinds of medications may sound counterintuitive for children with hyperactivity and/or low levels of attention, there is actually good reason behind the use of these pharmaceuticals.
Past studies have demonstrated a correlation between the development of ADHD and deficient levels of the neurotransmitters norepinephrine and dopamine – chemicals that are believed to work together to facilitate normal cognitive function and learning.
Dopamine is also known as the body’s reward chemical as it is activated when we experience pleasurable things such as food, sex, social approval, or drug (i.e cocaine) use.
Cannabis and ADHD
While those diagnosed with ADHD are generally more likely to develop drug habits, including alcohol, cocaine, and nicotine use, cannabis abuse is often the most singled out of these perceived problematic abuses. However, it remains unclear whether cannabis use in ADHD patients should automatically be considered as a misuse.
A growing number of people with ADHD have provided more insight into the reasons for their cannabis use, with many claiming that the drug has helped them with symptoms of both ADHD and associated comorbidities including anxiety, Tourette’s Syndrome, sleep disorders, depression, and PTSD.
Perhaps one of the most famous ADHD patients to speak out about his cannabis use is actor and comedian, Seth Rogen, whose parents recently gave an interview with The New York Times Magazine:
Seth’s father, Mark Rogen commented: “We had him on a strict diet that helped keep him in balance, but it wasn’t 100 per cent. Marijuana finally made his cells relax.”
The actor’s mother, Sandy Rogen, continued: “I knew when he was four that he would not be able to sit in school. We took him off dairy, wheat, sugar, yeast – everything good. But he was still in trouble at school, finding it hard to sit still.”
Dopamine and the Endocannabinoid System
The endocannabinoid system (ECS) is a neurological system that is expressed throughout the human immune and central nervous systems. This collection of neurotransmitters – known as endocannabinoids – receptors, and enzymes, has been found to play an important role in many cognitive functions, including mood, pain signalling, and memory.
In addition to the endocannabinoids that are produced in our own bodies, phytocannabinoids from the cannabis plant can also have a significant effect on these processes, making them an area of interest in developing medications for a number of conditions.
Furthermore, dopamine and the ECS are believed to have a bidirectional relationship, meaning that cannabinoids may also be beneficial in the management of ADHD symptoms.
Is there any evidence?
While research is still in its infancy, one research study demonstrated a direct link between ADHD symptoms and behaviours and the impairment of the ECS. This study revealed that CB1 signalling was significantly impaired in a rodent model of ADHD with a dopamine transporter model.
Other research has shown that THC, a CB1 agonist, is linked to the release of dopamine which at least in part, may play a role in the pleasure – or ‘high’ – experienced when using cannabis products. This relationship may explain why some people with ADHD have experienced benefits from cannabis use similar to those from pharmaceutical drugs such as Ritalin and Adderall.