“Nicotine and cocaine are stimulant drugs and may have been used to counter symptoms of inattention, and alcohol or marijuana may have been used to reduce hyperactivity,” study co-author Eugene M. Dunne, MA, a doctoral candidate in clinical and health psychology at the University of Florida, told Psychiatry Advisor. “Another explanation is that some patients with ADHD tend to act more impulsively, which increases risk for substance use.”
In line with those explanations are results from another 2014 study3 from Addictive Behaviors investigating the link between substance use and dependence and the subtypes of ADHD. The researchers used data from an ethnically diverse sample of 33,588 U.S. adults from the National Epidemiologic Survey of Alcohol and Related Conditions (NESARC) conducted by the National Institute on Alcohol Abuse and Alcoholism (NIAAA).4 The results reveal a consistent association between substance use and abuse and the hyperactive-impulsive and inattentive subtypes of ADHD.
“Impulsivity underlies aspects of both the hyperactivity-impulsivity subtype of ADHD and substance use and misuse, and we speculate that a common predisposition to impulsive behaviors may be one of several contributors to the comorbidity,” study co-author Arpana Agrawal, PhD, an associate professor of psychiatry at Washington University School of Medicine in St. Louis, told Psychiatry Advisor.
That commonality may have a genetic basis, as supported by research that appeared in the journal European Neuropsychopharmacology in 2013.5 “Both ADHD and substance abuse are for a large part genetically determined, and family studies have shown that both disorders occur in the same families, indicating a shared genetic basis,” Pieter-Jan Carpentier, MD, a clinical psychiatrist in the Netherlands who co-authored the study, told Psychiatry Advisor.