Many Youth With ADHD Fail to Take Stimulants as Prescribed

More than half of children and adolescents with attention-deficit/hyperactivity disorder (ADHD) may not be taking stimulant medications as prescribed, according to a report in Psychiatric Services in Advance.

“These findings [underscore] the need for active efforts to better understand the problem and develop approaches to help mitigate it, especially in primary care settings,” wrote lead author Joseph Biederman, M.D., chief of the Clinical and Research Programs in Pediatric Psychopharmacology and Adult ADHD at Massachusetts General Hospital, and colleagues.

The researchers analyzed prescription and sociodemographic data from the Partners Health Care Research Patient Data Registry of Massachusetts General Hospital for 2,206 patients aged 4 to 17 years who had been prescribed any of the following stimulants between January 1, 2015, and December 31, 2016: amphetamine/dextroamphetamine, dextroamphetamine, dexmethylphenidate, lisdexamfetamine, and methylphenidate. The researchers included medications prescribed as a single prescription (30-day supply) and medications with prescriptions postdated by up to three months (60- or 90-day supply).

Biederman and colleagues defined a patient as being “adherent” if a single index prescription was followed by a second prescription within 90 days.

In cases in which index prescriptions were postdated by two months (that is, two prescriptions written on the same date), a patient was deemed adherent if a third prescription was filled 31 to 120 days after the first prescription. In cases in which index prescriptions were postdated by three months, a patient was considered adherent if the fourth prescription was filled 61 to 150 days after the first prescription.

Of the 2,206 patients, 95% had single index prescriptions, 4.9% had prescriptions that were postdated by two months, and 0.5% had prescriptions postdated by three months. Only 46% (n=1,023) of patients met the researchers’ criteria for medication adherence, indicating that they refilled their stimulant prescriptions quickly enough to be considered consistently medicated.

Patients who received prescriptions from psychiatric clinics rather than nonpsychiatric clinics had a small but significantly greater likelihood of adherence to treatment. “This finding may reflect better familiarity with ADHD within psychiatry that may help patients become more adherent to stimulant treatment,” Biederman and colleagues wrote. The findings also suggest that efforts to improve medication adherence for ADHD are most needed in primary care settings, the authors noted. Additional analysis revealed that children tended to adhere to the medication regimen somewhat more than adolescents, and adherence was slightly better in boys than in girls.

Biederman and colleagues noted that low adherence may reflect several factors: the complexity of renewing prescriptions for stimulants, which are schedule II medicines; negative side effects of stimulants, such as lack of appetite and difficulty sleeping; or parents’ ambivalence about their child taking medications for ADHD.

“Low adherence may also stem from misinformation or biases about stimulants in the media,” the authors wrote.

But Biederman and colleagues acknowledged that there may be mitigating factors that account for the findings, apart from stigma or poor adherence. “Some patients may take stimulant medications on schooldays only; thus, failure to refill a prescription on time may not reflect nonadherence,” they wrote. “It is also possible that the diagnosis of ADHD may have been inaccurate, thereby the index prescription may have been inappropriate.”

They concluded, “More research is needed to clarify the causes of low medication adherence in ADHD to develop appropriate measures to mitigate them.”

Child psychiatrist David Fassler, M.D., said the results of the study are consistent with previous findings. “Adherence to treatment with stimulants for ADHD is highly variable and influenced by multiple factors,” he told Psychiatric News. “However, compliance is generally enhanced when the medication is utilized as a component of a comprehensive plan, individualized to the needs of the child and family.”

Fassler, a clinical professor of psychiatry at the Robert Larner, M.D., College of Medicine at the University of Vermont, added, “Although the findings of the current study are interesting, the design did not allow an assessment of safety, side effects, symptom reduction, or overall clinical efficacy. Ultimately, these are the significant outcome parameters for parents and practicing clinicians.” ■

“Evidence of Low Adherence to Stimulant Medication Among Children and Youths With ADHD: An Electronic Health Records Study” is posted here.