乌鸦传媒

Despite their clinicians鈥� best intentions, large proportions of patients with attention deficit hyperactivity disorder (ADHD) stop taking their medications within a year, say the authors of a new report published in Lancet Psychiatry.¹

Recent estimates show that ADHD affects an estimated 9.8% of children in the U.S.,² and that approximately 2% to 3% of adults worldwide experience persistent symptoms following childhood onset of ADHD.³ Recommended treatment varies across ages and countries, but includes parental training in behavioral management, educational interventions, environmental modification, and pharmacotherapy.⁴

Children and adults discontinue their ADHD pharmacotherapy for a variety of reasons, including inadequate symptom control, patient or family dislike of medications, and disease- or treatment-related complications.^5,6

A wide-ranging study, covering multiple countries

This retrospective, observational study, conducted using data from Australia, Denmark, Iceland, the Netherlands, Norway, Sweden, the U.K., and the U.S., as well as the region of Hong Kong, aimed to evaluate discontinuation and persistence rates for ADHD pharmacotherapy among children, adolescents, and adults. Except in the U.K., where only prescription records were available, pharmacy dispensing data were used. Data for most regions, with the exception of Australia, Denmark, and Norway, covered the period from January 1, 2009, to December 31, 2020.

Eligible patients were those ages 3 years or older who had initiated pharmacotherapy for ADHD between 2010 and 2020. Patients were grouped based on their age at the time of first ADHD dispensed medication as children (ages 4 to 11 years), adolescents (12 to 17 years), young adults (18 to 24 years), or adults (鈮�25 years).

Data were collected regarding receipt of 4 stimulants (methylphenidate, amphetamine, dexamphetamine, and lisdexamfetamine) and 2 nonstimulants (atomoxetine and guanfacine). The initiation date was set as the date of the first recorded dispensed prescription of a medication following at least a 12-month period without an ADHD medication. 

Discontinuation was defined as 180 days or more between 2 dispensed medications. Switches between meds were not considered discontinuations unless a gap of more than 180 days occurred. 鈥淲e selected a cutoff of 180 days or more without a dispensing to ensure we captured clinically meaningful medication breaks rather than shorter treatment breaks,鈥� the authors explained.¹ Across countries and ages, the proportion of patients who discontinued treatment was similar between males and females despite more males receiving ADHD medications than females.

What the data revealed about compliance

In total, data on more than 1.2 million patients (60% male/40% female) were included in the analysis. The median age at first dispensed prescription ranged from 16 to 21 years in most locations, but patients were younger in Australia and the U.K. (11 years), as well as in Hong Kong (8 years).

In all places, the most commonly prescribed first medication was methylphenidate, followed by atomoxetine (in most countries). Dexamphetamine was the second most commonly dispensed medication at initiation in the U.S. and Australia.

Patients in the U.S. had the lowest median time to first discontinuation (142 days), whereas those in the U.K., Norway, and Sweden took the longest to stop their medication (a median of 432, 426, and 411 days, respectively). At 1 year, 65% of children, 47% of adolescents, 39% of young adults, and 48% of adults remained on treatment. At 5 years, these percentages dropped to 24%, 9%, 10%, and 15%, respectively. The highest proportion of discontinuations occurred at ages 18 and 19 years.

The proportions of patients taking ADHD medication at 5 years鈥攊ncluding patients who had stopped then re-initiated ADHD medication鈥攚ere 50% to 60% of children and 30% to 40% of adolescents and adults. 鈥淭his pattern of on-and-off treatment might be linked to the dynamic nature of ADHD,鈥� the authors hypothesized.¹

How to interpret the results

In a news release, the study鈥檚 corresponding author, Zheng Chang, PhD, Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, said that 鈥渋t鈥檚 unlikely that so many people discontinue their treatment because their ADHD symptoms have remitted, meaning that the high rate of early discontinuation may be a major barrier to effective treatment.鈥�⁷

The high levels of discontinuation occurring at 18 and 19 years coincides with the transition from pediatric to adult mental healthcare, and difficulty in transitioning may account for the relatively higher levels of discontinuation during this time, Dr. Chang and his colleagues suggested. 

During early adulthood, a lack of parental support for medication management, views that ADHD is a childhood- or education-related disorder, adverse effects or limited effectiveness of medication, and dependence concerns may contribute to high rates of discontinuation. 

The researchers concluded that 鈥渓ate adolescence and early adulthood seem to be an important window for targeted interventions aimed at reducing premature medication cessation in individuals for whom treatment remains warranted and effective.鈥�¹

Published: January 25, 2024