As Adderall shortages persist – driven in no small part by a dramatic jump in ADHD diagnoses – new research shows that the growth is limited to older patients. More specifically, patients over 18 boasted higher average fill rates than any of the younger age groups.
It’s in the shadow of this chaotic market that a new Swedish population-based study calls into question just how representative randomized controlled trials (RCTs) are for ADHD medications. Naturally, this paper – which appears in The Lancet Psychiatry, sparks concerns about how relevant some of these trial findings are to real-world settings.
The study, which covered nearly 190,000 patients, found that more than half of them wouldn’t have qualified for traditional ADHD medication RCTs. As a result, the researchers suggest integrating real-world evidence into treatment guidelines. This could help address the complexities of ADHD in diverse patient populations.
So, What’s the Problem?
The researchers looked at individuals four and older who’d received an ADHD diagnosis and who began pharmacological treatment between 2007 and 2019. The team pulled the data from the Swedish national registries. The research team then applied eligibility criteria culled from 164 RCTs in the international MED-ADHD dataset to identify those who would’ve been excluded from trials. The results revealed that:
- 53 percent of the individuals couldn’t have qualified for RCTs. Adults had the highest ineligibility rate – at 74 percent – followed by adolescents, 35 percent, and children at 21 percent
- Ineligible individuals were more likely to switch medications and a little less likely to abandon treatment compared to those who were eligible.
The data also showed that ineligible individuals consistently faced higher risks of adverse outcomes. For example, these patients had:
- Nearly 10 times the rate of psychiatric hospitalizations within a year of starting treatment.
- Much higher rates of specialist care visits for substance use disorders (14.8 times), depression (6 times), and anxiety (11.6 times).
- And a 31 percent higher rate of accidents or injuries.
But What Does it Mean?
The findings underscore the limited relevance of RCTs for ADHD medications to real-world populations. These trials typically exclude anyone with comorbid psychiatric or medical conditions. Unfortunately, they also represent a sizable segment of those diagnosed with ADHD.
For example, conditions such as major depressive disorder (MDD), anxiety, and substance use disorders — frequently appearing with ADHD — are ordinary reasons for trial exclusion. As a result, this drives a wedge between the relatively homogeneous trial populations and the more diverse, complex patient populations that actually show up in clinical practice.
The study also highlighted the challenges of managing ADHD in excluded groups. For example, kids faced an increased risk of medication discontinuation, probably because of heightened concerns about side effects or struggles fine tuning the treatment. On the other hand, adults and adolescents exhibited higher rates of treatment switching, illustrating the complexity of the clinical setting.
Expanding Existing ADHD Research
The authors insist that this is the first study to explore ADHD medication RCT representation using a large, nationwide cohort with a huge international dataset. This paper, they argue, offers critical empirical evidence of the gap between RCT evidence and clinical practice.
Finally, the authors call for a more inclusive approach to ADHD research that includes:
- Launching studies with broader inclusion criteria to better capture the diversity of real-world populations.
- Assimilating data from observational studies to supplement traditional RCTs.
- Focusing on groups that are normally overlooked so that researchers can better understand treatment trajectories and outcomes.
Further Reading
ADHD’s Fluctuating Nature Challenges What We Think We Know
Management of Adolescents and Young Adults With Attention-Deficit/Hyperactivity Disorder
ADHD Might Have Been an Early Evolutionary Edge
