Nonadherence to ADHD Meds: Red Flag for Illicit Drug Use?

Nancy A. Melville

February 03, 2016

Urine screens of patients prescribed medications for the treatment of attention-deficit/hyperactivity disorder (ADHD) show that nonadherence is common, and those who who do not adhere to their regimens show increased rates of illicit drug use compared with their compliant counterparts, new research indicates.

"What our results show are objective data to a subjective problem," coauthor Patricia Woster, PharmD, of Ingenuity Health, in Baltimore, Maryland, told Medscape Medical News.

"Patient adherence is often assessed with methods such as refill records or patient self-reports, but these findings reflect objective data showing that in 32.9% of patients who are prescribed with a diagnosis of ADHD, the medication was not found."

The research, presented at the annual meeting of the American Professional Society of ADHD and Related Disorders, involved urine samples of 4094 patients prescribed an amphetamine or methylphenidate medication for ADHD that were submitted to the Ameritox laboratory between July 1, 2014, and June 30, 2015.

Among the patients, 3199 (78.1%) were prescribed an amphetamine; 862 (21.1%) were prescribed methylphenidate; and 33 (0.8%) were prescribed both.

Overall, the data showed that the prescribed ADHD medication was not detected in the urine samples of 1348 (32.9%) patients.

Among patients who were nonadherent to their regimen, there were significantly higher rates of detection of nonprescribed opioids (ajusted odds ratio [aOR], 1.41; 14.3% vs 9.7%), benzodiazepines (aOR, 1.37; 8.9% vs 6.3%), tetrahydrocannabinol (THC) (aOR, 1.64; 20.7% vs 11.9%), and cocaine (aOR, 1.69; 1.7% vs 0.9%).

Overall, 38.7% of patients who were nonadherent to their ADHD drug regimen tested positive for illicit drug use, compared with 24.8% of patients who were adherent (aOR 1.71).

For patients prescribed amphetamines, the rate of nonadherence was higher in comparison with those prescribed methylphenidate (33.8% vs 27.8%; aOR, 0.76; 95% confidence interval [CI], 0.63 - 0.91).

The study further showed significant variation in nonadherence with respect to age groups, ranging from a high of 41.6% of patients aged 20 to 29 years (n = 800) to the lowest level of 24.4% ofpatients aged 60 years or older (n = 115; aOR, 0.34).

Nonadherence rates were similar between men and women (33.2% vs 32.7%). The rates in 2015 were similar to those in 2014 (31.3% vs 34.5%).

"The data also suggest that potential nonadherence to prescribed stimulant ADHD therapy is associated with the use of marijuana, nonprescribed opioids, and nonprescribed benzodiazepines," the authors write.

The findings are consistent with previously reported evidence of nonadherence to ADHD drugs, the investigators note.

Additionally, evidence of ADHD drug diversion has been reported in numerous studies, including research published in 2014.

Dr Woster also noted findings from a report from the Substance Abuse and Mental Health Administration's Drug Abuse Warning Network that showed that the number of emergency department visits related to the nonmedical use of central nervous system stimulants among adults aged 18 to 34 years soared from 5605 in 2005 to 22,949 in 2011.

"From these findings, there definitely appears to be an increase in experimentation with these drugs," she said.

The study sheds important light on the concerns of nonadherence to ADHD drugs, commented Brooke S. G. Molina, PhD, professor of psychiatry and psychology at the University of Pittsburgh Medical Center, in Pennsylvania.

"The association with illicit drug use is not terribly surprising, but to our knowledge, it has only been speculated and not studied in this way," she said in a joint comment with psychiatrist Srihari Bangalore, MD, and clinical coordinator Heidi Kipp, also of the University of Pittsburgh.

The speakers noted that a limitation of the study is that urine samples and medication use do not always correspond.

"For example, a short-acting stimulant could be completely out of the system before the urine sample is taken, so understanding the timing of last dose taken with respect to collection of the urine sample is important," they said.

"Moreover, many adults with ADHD take their stimulant medications [as needed]. Therefore, it's entirely possible that they didn't take their medication, by design, on a day that a urine sample was collected," they added.

"In addition, it's not clear whether the urine sample results were collected following patient report they took their medication or not."

They noted that a variety of factors are associated with ADHD drug nonadherence.

"Clinically, the main causes are forgetting, disorganization, such as not getting prescription refilled, needing oversight or reminders, misinterpreting need on a given day, diversion, including sharing or selling, or side effects."

Measures to improve adherence can vary from patient to patient, they added.

"Good clinical care considers an individualized dosing schedule that maximizes treatment effects, minimizes side effects, and assesses need for PRN vs 7-day-per-week prescribing. This kind of clinical care will increase adherence."

The study was funded by Ingenuity Health, a service of Ameritox Ltd. Dr Woster is an employee of Ingenuity Health. Dr Molina, Dr Bangalore, and Heidi Kipp have disclosed no relevant financial relationships.

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