Young Adults With ADHD ‘Three Times More Likely’ To Become Addicted to Illegal Drugs

A study of 7,000 people suggests those with ADHD are more likely to have drug problems and that some may be self-medicating.
Max Daly
London, GB
Photo: Steve Parsons/PA Images via Getty Images)

Young adults with the behavioural disorder ADHD are three times more likely to become addicted to illegal drugs than those who do not have the disorder, a new study has found.

Carried out among nearly 7,000 Canadians aged 20 to 39, of whom 270 had attention deficit hyperactivity disorder, the University of Toronto study is part of a growing body of evidence linking ADHD with problem drug use. 


It found that half of people with ADHD had developed an addiction problem with any drug – including substances which are legal in Canada such as alcohol and cannabis – compared to 23 percent of those without ADHD.  

The difference was more pronounced with the use of more risky drugs. Those with ADHD were three times more likely to have become addicted to an illegal drug such as cocaine, heroin and meth, with 18 percent doing so compared to five percent who did not have the disorder. 

The Toronto study revealed strong links between people with ADHD and adverse childhood experiences, as well as with anxiety and depression. The authors of the report suggested that tough childhoods made it much more likely for people to suffer from both ADHD and substance use disorders. 

“Young adults with ADHD who also had mental health problems had greatly elevated rates of substance use disorders,” said study author Professor Esme Fuller-Thomson. 

“It may be that those with depression or anxiety issues are abusing substances as a way to ‘self-medicate’. Since these problems are so intertwined, health professionals who target this toxic trio of addictions, depression and anxiety may have better results than those who focus on only one of these issues at a time.”

A comprehensive literature review carried out by ADHD and addiction experts at Massachusetts General Hospital in 2014 concluded that “children and adolescents with ADHD are at an increased risk for various substance use disorders”.  It said that for young adults with dual ADHD and drug problems, “engagement, support, and treatment” was critical.


ADHD affects about three to five percent of children and two percent of adults in the UK and is more common in men and boys than women and girls. It is estimated around one in four prisoners in the UK have the disorder.

Scientists believe that some people with ADHD – which can cause inattentiveness, hyperactivity and impulsiveness – take illegal drugs as a way of self-medicating their condition, either to help them relax or focus. 

Apart from cognitive therapy, the most common treatment for ADHD is with prescription amphetamines, such as Adderall and Ritalin, which help people with the disorder to concentrate. 

“I know a lot of people with ADHD who self-medicate with stimulants,” Ciaran, a marketing executive from Liverpool in his late 40s who was diagnosed with ADHD two years ago, told VICE World News. 

Ciaran, who does not want to be named because he takes illegal drugs, said he has been on the waiting list to be treated for ADHD in his area for three years. “The reason people end up self medicating with illegal drugs is down to ignorance and stigma. The NHS does not allocate enough funding to this serious and well-documented condition so getting adequate care and medication is not easy.”


In the US, it is thought only one in five people with ADHD have been diagnosed and previous research has shown one in four teenagers with drug problems have the disorder. 

“It is helpful for those with ADHD to know that they have a high risk of substance abuse and substance dependence problems,” said Fuller-Thomson. “Hopefully awareness of this risk will help young adults with ADHD avoid situations that increase exposure to illicit drugs and overuse of alcohol or cannabis. 

“Health professionals should be aware of the strong link between ADHD and substance abuse, and therefore have targeted outreach and screening for substance dependence issues with their patients who have ADHD.”