What ADHD therapies increase drug abuse risk?

Choosing medication therapy to treat their child’s attention-deficit/hyperactivity disorder (ADHD) can be a tough call for parents, and many express concerns over whether stimulant medications open the door to future drug use.

A new study found, however, that children with ADHD who begin stimulant medication regimens earlier and stay on those routines for longer periods are less likely than even peers without ADHD to engage in future drug use.

The study, published in the Journal of the American Academy of Child and Adolescent Psychology, reveals that generally substance abuse was highest in children and adolescents with the latest onset and shortest duration of stimulant therapy. Those who reported only nonstimulant therapy also reported higher levels of substance abuse.

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More than 1 in 10 children aged 4 to 17 years-6.4 million children-have been diagnosed at some point with ADHD and roughly 75% are on medication to treat the disorder.

Clinical evidence supports the observation that children with ADHD are at higher risk of developing substance abuse problems. A 2013 study from the University of Pittsburgh Medical Center (UPMC) reveals that 35% of teenagers with ADHD had tried 1 or more drugs by age 15 years, compared with just 20% of teenagers without ADHD. For some, the problems become significant, with 10% of teenagers with ADHD progressing to substance abuse or dependence disorders compared with just 3% of adolescents without ADHD.

The study found that alcohol use was prevalent in both groups, but that cigarette and marijuana smoking were more prevalent among teenagers with ADHD. The UPMC study, however, found no difference in substance abuse rates between those being treated for ADHD and those who were not receiving treatment.

Researchers of the newest study, however, sought to prove the hypothesis that substance abuse increased risk is not tied to the stimulant therapy used to treat ADHD, according to the report.

The goal of the study was to determine to what extent ADHD medications play a role in the development of substance abuse. Researchers polled more than 40,000 high school seniors and found that teenagers who started stimulant medication for ADHD later (aged 10 to 14 years and 15 years and older) and for a shorter duration (less than 5 years) and those who used nonstimulant medications for ADHD had significantly higher odds of substance abuse compared with those who began stimulant therapy before age 9 years and used the medication for more than 6 years.

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The study revealed that 12.2% of high school seniors had been treated with some type of medication-both stimulant and nonstimulant-for ADHD. About 3% began treatment with stimulant medications before age 9 years; 2.9% began therapy between ages 10 and 14 years; and 3% began stimulant therapy at age 15 years or older. Another 3.2% were treated with nonstimulant medication only.

Gender differences also existed in the prevalence of stimulant therapy, according to study data, with 4.2% of males versus 2.1% of females treated with stimulant therapy in the preschool and elementary years. There was no difference, however, in the prevalence of nonstimulant treatment between males and females.

In terms of what types of drugs were abused and at what rates, researchers found that 22% of teenagers that began stimulant therapy before age 9 years and had continued it for 6 or more years reported binge drinking compared with 41% of teenagers that started stimulant therapy after age 15 years and had been treated for less than 2 years. The average for non-ADHD teenagers was 22.4%, and 30.8% of adolescents treated for ADHD with nonstimulant medications reported binge drinking.

Similar trends were visible for other drug use, with teenagers who had earlier onset, longer duration stimulant treatment for ADHD reporting cigarette smoking at a rate of 21.4%; marijuana use at 35.3%; cocaine use at 5.2%; and overall drug use at 68.5%, compared with teenagers with later treatment onset and shorter duration who reported cigarette smoking at 36.3%; marijuana use at 59.1%; cocaine use at 10.2%; and overall drug use at 85.6%. The average rates across the adolescent population are 16.4% for cigarette smoking; 31.5% for marijuana use; 3% for cocaine use; and 65% for overall drug use. Additionally, teenagers treated with nonstimulant ADHD medications reported rates of 29.7% for cigarette smoking; 42% for marijuana use; 7.8% for cocaine use; and 74.8% for overall drug use.

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Sean Esteban McCabe, PhD, research professor and research faculty chair at the Institute for Research on Women and Gender at the University of Michigan in Ann Arbor, says ADHD stimulant use among teenagers is rising, although it’s estimated that just 1 in 10 children with ADHD have been diagnosed and are being treated for the disorder.

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“ADHD itself puts children at increased risk for substance use and substance use disorders. Clinical evidence shows that ADHD stimulant medications do not increase the risk for substance use, but there have been no national studies of large probability-based samples until the present study. We were somewhat surprised by the high rates of medication therapy for ADHD with nearly 1 in every 8 high school seniors in the United States reporting ever using stimulant or nonstimulant medication therapy for ADHD,” McCabe says.

Usage rates illustrate the need for further study of ADHD medications and their lasting effects, he says.

“The findings of the present study reinforce the importance of early detection and persistent treatment of ADHD (including medication when necessary) in reducing substance-related outcomes during adolescence (to the level of the general population) [and] help to contradict the idea that the longer a child is on prescription stimulants, the more likely he or she will develop substance-related problems in adolescence,” McCabe says. “Conversely, we found that longer duration of stimulant medication therapy for ADHD was associated with lower rates of substance use during late adolescence as compared to shorter duration of stimulant medication therapy for ADHD at all developmental periods, especially among individuals who initiated stimulant medication therapy for ADHD in preschool, elementary school, and middle school. Based on the study findings, prospective studies with large samples of ADHD and non-ADHD children and adolescents are necessary to more carefully evaluate the potential consequences of stimulant exposure at high-risk developmental periods such as adolescence.”

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McCabe says although the study indicates some association between medication timing and probability of later substance abuse, there is a lot that parents can do to influence their children.

“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,” he says. “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; safely storing their controlled [medication] in the household and not sharing with others; consulting with the prescriber if they have any questions such as adjusting dosing; and properly disposing their controlled medication.”