University study reveals link between ADHD medication and substance use in adolescence

Tuesday, June 28, 2016 - 11:18pm

According to a recent University of Michigan study, duration, type of attention deficit hyperactivity disorder medication and age of ADHD onset are strongly correlated to substance use during the adolescent years.

Sean McCabe, research professor for the University's Institute for Research on Women and Gender, conducted the study with Kara Dickinson, a former intern at the UM IRWG; Brady West, a research associate professor at the Institute for Social Research; and Dr. Timothy Wilens, who specializes in psychiatry, from Harvard University and Massachusetts General Hospital.

“Our research team has worked with children and adolescents with attention deficit hyperactivity disorder and observed the incredible impact appropriate treatment for ADHD, including medication when necessary, can have in their lives,” McCabe said.

McCabe’s study was the first to utilize large data samples of American youth to provide national-level information on ADHD medication, duration of treatment, age of ADHD onset and substance use behaviors.

According to a previous study, about 6.4 million American youth aged 4 to 17 — about one in 10 U.S. children and adolescents — have been medically diagnosed with ADHD in their lifetimes. Among those with a history of ADHD diagnosis, more than 80 percent currently have ADHD, and more than two-thirds take medication to treat the condition.

The experiment used nationally represented samples of 40,358 high school seniors — of which 3,539 were prescribed stimulant medication, the most common ADHD medication, and 1,332 were prescribed nonstimulant medication therapy, a less common alternative — from 10 separate cohorts in the years 2005 to 2014. The students were surveyed with self-administered questionnaires.

Stimulant therapy includes Ritalin, Adderall, Concerta and Dexedrine, while nonstimulant therapy includes medication such as Strattera, Intuniv, Wellbutrin and Provigil. According to the Cleveland Clinic, stimulant medication controls impulsive actions and improves focus by increasing dopamine in the brain, while nonstimulant medication regulates these ADHD symptoms by working on the neurotransmitter called norepinephrine.  

McCabe said he and his colleagues were surprised by how commonly ADHD medications were being used among adolescents.

“We were somewhat surprised by the high rates of medication therapy for ADHD, with nearly one in every eight high school seniors in the U.S. reporting ever using stimulant or nonstimulant medication therapy for ADHD,” McCabe said.

The researchers found that initiating stimulant ADHD medication between 10 to 14 years of age, shortening the duration of the treatment to two or fewer years, and using nonstimulant medication therapy all correlated with higher rates of substance use — such as drinking, smoking cigarettes and drugs like marijuana or cocaine — and substance use disorders during adolescence. 

The researchers saw the opposite trend for those who started stimulant medication early and stayed on medication for a longer period of time.

“We also found that children who initiated stimulant medication to treat ADHD at age 9 or earlier and continued for a duration of six years or more were less likely to engage in adolescent substance use,” McCabe said. “Most notably, the risk of substance use in adolescents who had been treated at an earlier age and for a longer duration with stimulant ADHD medications was the same as for the general population of children.”

McCabe said the results from this research study can greatly influence the everyday lives of families with children with ADHD.

Parents and older siblings can serve as good role models for their younger siblings in regard to developing safe practices with prescription medications, according to McCabe.

“The findings of the present study suggest several steps parents can take to keep kids from substance abuse, including early detection and appropriate treatment for ADHD and other childhood disorders,” McCabe said. “Parents are also in an excellent position to serve as good role models regarding their own relationship with controlled medications by taking their own controlled medication as prescribed.”