Half of younger adults with attention-deficit/hyperactivity disorder (ADHD) report having experienced a substance use disorder in their lifetime, according to findings published in Alcohol and Alcoholism.

Controlling for a lifetime history of depression and anxiety, however, led to the largest attenuation of the link between ADHD and substance use disorders, researchers reported. Childhood adversities and socioeconomic factors also attenuated the ADHD-substance use disorder relationship.

“These results emphasize the importance of addressing depression and anxiety when providing care to those with co-occurring ADHD and substance use disorder,” said lead author Esme Fuller-Thomson, PhD, a professor at University of Toronto. “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.” 

The study included a nationally representative sample of adults between the ages of 20 and 39 from the Canadian Community Health Survey-Mental Health. Researchers compared 270 respondents with ADHD with 6602 respondents without ADHD.

ADHD Stimulant Treatment Plan Should Include Monitoring for Substance Abuse

After controlling for factors such as age, race, income, education, childhood adversities, and other mental illness, respondents with ADHD were 69% more likely to have had a lifetime substance use disorder compared with those without ADHD, according to the study. Alcohol use disorder was most common, with 36% of respondents with ADHD reporting lifetime alcohol use disorder. Lifetime prevalence of cannabis use disorder was 23% in those with ADHD, while lifetime drug use disorder other than cannabis was reported by 18% of respondents with ADHD.

“One potential explanation for the extremely high rate of illicit drug use among those with ADHD is the accelerated gateway hypothesis,” said coauthor Senyo Agbeyaka, MSW, a social worker at University Health Network in Toronto. “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.”

The findings shine a light on the vulnerability of young adults with ADHD to substance use disorders, the researchers pointed out.

“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,” said Dr Fuller-Thomson.

References

Fuller-Thomson E, Lewis DA, Agbeyaka S. Attention-deficit/hyperactivity disorder and alcohol and other substance use disorders in young adulthood: findings from a Canadian Nationally representative survey. Alcohol Alcohol. Published online August 3, 2021. doi: 10.1093/alcalc/agab048

Half of adults with ADHD have had a substance use disorder. News release. University of Toronto. August 25, 2021. Accessed August 27, 2021.