ADHD and Addiction May Share Genetic Basis

In addition to the direct challenges associated with attention-deficit/ hyperactivity disorder (ADHD), there is ample evidence linking it with elevated rates of substance abuse, and several recent studies add to the growing body of research on the topic.

A prospective longitudinal study1 published last year determined that ADHD symptoms in early childhood predicted substance abuse in the teen years. Researchers from three universities in the United States followed young children with ADHD and a non-ADHD control group until they reached the age of 18, receiving annual reports of their ADHD symptoms and substance use. Among adolescents with ADHD, the findings show a higher likelihood of trying cigarettes, starting alcohol use at an early age, and more frequent marijuana use. Additionally, after trying those substances the first time, the ADHD group was four to five times more likely to escalate to heavy use of cigarettes and marijuana. 

A study2 funded by the National Institute on Drug Abuse (NIDA), published in Addictive Behaviors in 2014, adds support to these findings from the other direction, so to speak. Researchers examined the substance use history of 941 drug-using African-American and Caucasian adults in Baltimore, approximately 13% of whom reported a history of ADHD. They found that those with ADHD had begun using alcohol, cigarettes, marijuana and cocaine at younger ages.

The results also support the “accelerated gateway model” of drug use, showing that experimentation with tobacco or alcohol at younger ages, for example, led to earlier progression to more serious drugs like marijuana and cocaine. One possible reason for the earlier drug use among adults with ADHD may pertain to attempts to self-medicate.