close-up shot of depressed young man with glass of whiskey


TORONTO, Ontario — Half of young adults with attention deficit hyperactivity disorder (ADHD) also end up dealing with substance abuse issues, a new study finds. Researchers from the University of Toronto say along with an increased risk of using drugs and alcohol, a quarter of adults with ADHD also have a history of depression.

In comparison to the half of adults between 20 and 39 years-old with ADHD having substance use disorders, just 23.6 percent of young adults without ADHD deal with these issues. Even after factoring in age, race, income, education, childhood adversities, or other mental illness, young adults with ADHD are 69 percent more likely to develop a substance abuse disorder.

Moreover, the study finds 27 percent of adults with ADHD have a history of depression in comparison to 11 percent of those without the neurobiological disorder.

“These results emphasize the importance of addressing depression and anxiety when providing care to those with co-occurring ADHD and SUD,” says lead author Esme Fuller-Thomson, a professor at University of Toronto’s Factor-Inwentash Faculty of Social Work, in a media release. “Individuals with untreated depression and anxiety may self-medicate to manage the symptoms of an untreated psychiatric disorder, which can result in greater substance use.”

Childhood trauma plays a role too

For those with ADHD, a difficult upbringing can make their condition even worse. Researchers find those with ADHD experience higher levels of physical abuse (35%) or sexual abuse (11%) before the age of 16. With that in mind, the study notes there’s a strong connection between childhood adversities and substance use disorders (SUD) later on.

“Childhood maltreatment may disrupt emotional regulation and the neuro-development of children, which may predispose them to later developing substance dependence,” says co-author Danielle Lewis, a graduate of the University of Toronto’s Masters of Social Work (MSW) Program.

Drinking problems rank as the most common SUD among young adults with ADHD. The study finds 36 percent deal with an alcohol use disorder, with cannabis use disorders (23%) following as the next most common SUD. Researchers add young adults with ADHD are three times more likely to abuse illicit drugs in comparison to those without ADHD (18% vs 5%).

“One potential explanation for the extremely high rate of illicit drug use among those with ADHD is the accelerated gateway hypothesis,” explains co-author Senyo Agbeyaka, a recent University of Toronto MSW graduate. “This theory posits that people with ADHD tend to initiate substance use at a younger age, resulting in riskier use and greater problem severity in adulthood.”

“There is a clear need to develop prevention and treatment programs to address substance use issues among those with ADHD, while also promoting mental health and addressing childhood adversities,” Fuller-Thomson concludes.

The findings appear in the journal Alcohol and Alcoholism.

About Chris Melore

Chris Melore has been a writer, researcher, editor, and producer in the New York-area since 2006. He won a local Emmy award for his work in sports television in 2011.

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