Link between prenatal drug use and ADHD

Prenatal use of alcohol, tobacco and cannabis has all been independently associated with adverse health impacts on the baby. But many people who use these substances during pregnancy aren't using them in isolation.

"What we know from people's habits is that most people are co-using substances," says Jennie Ryan, Ph.D., CPNP-AC, a nursing researcher at Thomas Jefferson University.

In a new study in the American Journal of Preventive Medicine examining how patterns of prenatal substance use impact attention-deficit/hyperactivity disorder (ADHD) diagnoses in children, researchers found that co-use of alcohol and tobacco, and use of cannabis alone, posed the greatest risk.

The study examined prenatal alcohol, tobacco and cannabis use alone and in combination with each other, says Dr. Ryan, the lead author. The strongest association was with alcohol and tobacco co-use during pregnancy—about four times greater odds of parent-reported ADHD in the child.

"These are two of the most readily available substances," Dr. Ryan says, "so it's important to educate pregnant people about this risk."

The next strongest association was with cannabis-only use, about two times greater odds of parent-reported ADHD. Surprisingly, Dr. Ryan says, cannabis combined with other substances did not pose as strong an ADHD risk.

The research data came from the Adolescent Brain Cognitive Development (ABCD) Study, a longitudinal repository of almost 12,000 diverse children and families across the United States. But while the ABCD Study is a large and rich data set, Dr. Ryan says it does not include ADHD diagnoses for parents. This is a notable limitation because there is a genetic component to ADHD.

The next step? Dr. Ryan is now using the ABCD Study's longitudinal data to examine how the treatment of ADHD in children, such as medications or cognitive behavioral therapy, impacts their risk of developing substance use disorder later in life.