Study Assesses Association Between Weight Gain, ADHD Medication

Studies have suggested that stimulant use is associated with growth deficits and with lower body mass index (BMI) in children with attention-deficit/hyperactivity disorder (ADHD), compared with peers without the disorder. Paradoxically, newer evidence increasingly suggests a link between ADHD and obesity among both children and adults. A study published March 18 in Pediatrics provides some insight into this clinical conundrum.

Researchers from Johns Hopkins Bloomberg School of Public Health and the Geisinger Center for Health Research conducted the first longitudinal study that assessed the impact of ADHD diagnosis and stimulant use on BMI trajectories in children.

“Given the dramatic rise in ADHD diagnosis and stimulant treatment for it in recent decades, this is an interesting avenue of research regarding the childhood obesity epidemic, because the rises in each of these roughly parallel one another,” Brian Schwartz, M.D., M.S., lead investigator and a professor of epidemiology and medicine, told Psychiatric News.

According to the Centers for Disease Control and Prevention, ADHD is one of the most prevalent psychiatric disorders among school-aged children and adolescents in the United States—affecting 11 percent of the population. Because of such high incidence rates, noted the authors, stimulant medications intended to treat ADHD are the second most commonly prescribed medications among youth.

Potential side effects of stimulant medication use include weight loss as a result of appetite suppression, but according to Schwartz and colleagues, cross-sectional data suggest that ADHD can be a risk factor for obesity. “This is a bit paradoxical,” Schwartz said in an interview. To unravel such paradoxical findings, Schwartz emphasized that it was crucial to independently investigate the consequences of ADHD diagnosis and long-term stimulant drug use on BMI factors in youth.

Schwartz and his team analyzed electronic health records from 163,820 children aged 3 to 18 who were divided into four groups: those with an ADHD diagnosis and stimulant prescriptions, those with an ADHD diagnosis without stimulant prescriptions, those without an ADHD diagnosis but with stimulant prescriptions, and those with neither an ADHD diagnosis nor a stimulant prescription (controls).

The results showed that youth with ADHD that was untreated with a stimulant had consistently higher BMIs throughout childhood than those without an ADHD diagnosis or those who were taking prescribed stimulants. Among children who were taking stimulants for ADHD or another condition, an earlier age for drug initiation and longer duration of drug use were associated with slow BMI growth in early childhood, but also was associated with a rapid surge in BMI in late adolescence—typically after discontinuation of the medication.

“These are interesting and new findings for us,” Schwartz told Psychiatric News. “The delayed growth [of BMI] while on stimulants was supported by prior evidence, but we had no knowledge of a BMI rebound after discontinuation of stimulants.”

Though the findings were unexpected, Schwartz stated that the current results do offer some explanations for previous findings that suggested an association between ADHD and adult obesity. “Now, the big question is how long does the [rapid] BMI rebound continue into adulthood?” commented Schwartz.

As ADHD and stimulant use continues to rise with rates of obesity in youth, Schwartz stated that clinicians should assess and evaluate BMI annually in youth receiving stimulants for treatment of ADHD, and present parents with alternative options such as cognitive behavioral therapy—which has no known BMI rebound effect—that may also be effective for the management of ADHD.

The study concluded that as the field of ADHD advances, “future research should examine how obesity prevention interventions may be best tailored and delivered to families with children who have ADHD and comorbidities.”

The study was supported by the National Institutes of Health. ■

An abstract of “Attention-Deficit Disorder, Stimulant Use, and Childhood Body Mass Index Trajectory” can be viewed here.