Health
Different day, different diagnosis?
Research indicates a surge in ADHD diagnoses on Halloween, underscoring the implications of cognitive bias in healthcare.
Anupam B. Jena (left) and Christopher Worsham.
Niles Singer/Harvard Staff Photographer
In healthcare, obtaining an accurate diagnosis is the initial step. Nevertheless, numerous conditions, such as attention deficit hyperactivity disorder (ADHD), necessitate doctors to depend on more subjective measurements, including observation of symptoms or behaviors. This vulnerability allows cognitive biases and external circumstances to sway medical evaluations. A recent publication in the National Bureau of Economic Research, “Halloween, ADHD, and Subjectivity in Medical Diagnosis,” revealed an opportunity for a natural experiment during a holiday known for stimulating hyperactivity in children. Researchers were curious if shifts in young patients’ behaviors—stemming from the thrill of dressing up and gathering candy during Halloween—affect ADHD diagnoses, leading them to analyze data from over 100 million pediatric visits. They discovered a 14 percent rise in childhood ADHD diagnoses on Halloween compared to ten adjacent weekdays.
We interviewed two authors of the study — Anupam B. Jena, the Joseph P. Newhouse Professor of Health Care Policy at Harvard Medical School, and Christopher Worsham, an assistant professor of medicine at HMS — regarding their conclusions. This discussion has been condensed and edited.
How is ADHD identified?
Worsham: In informal terms, pediatricians and child mental health professionals diagnose ADHD over time. The objective is to evaluate a pattern of behavior throughout school and home life, collecting insights from both parents and teachers. However, the definitive diagnosis occurs on a specific day. Therefore, on the day the physician renders the diagnosis, the circumstances present could sway whether a borderline case is recognized as ADHD or not.
Jena: While there’s a formal process involved in making a diagnosis, ultimately, one must be established. It reflects a snapshot of that particular day, rather than a laboratory examination.
How does subjectivity factor in?
Worsham: The diagnostic criteria for ADHD inherently include subjectivity. Among the criteria are: “Is this child fidgeting? Is this child frequently moving? Are they exhibiting restlessness? Are they speaking when they shouldn’t be?” If you are a kindergarten educator evaluating a child’s behavior, you are comparing it to your expectations for how a kindergartner should behave. This perception will differ from one teacher to another.
On Halloween, we can specifically observe the subjectivity of the physician. They will have that critical element, which is how the child is behaving in their presence on that day.
Jena: You might anticipate a reaction to Halloween in a child who has ADHD or faces risk factors for it because it is an engaging holiday. Halloween serves as a stress test.
Why does misdiagnosis matter?
Jena: Consider a scenario where two or three children receive diagnoses. Two might get diagnosed on a typical non-Halloween day, and three on Halloween. That third child represents an additional medication prescription.
Worsham: This ties into the broader discourse regarding ADHD. Almost 10 percent of children are getting diagnosed, with a higher prevalence among boys than girls. This raises questions: Is this genuinely a disorder, or is it part of the normal range? Are medications the appropriate solution? This is a substantial debate in both medical and educational communities. Concerns exist regarding the potential for both overdiagnosis and overtreatment of ADHD in children who may not benefit and might suffer from the medications. Additionally, there’s apprehension about underdiagnosing and undertreating children from historically overlooked populations.
Does your research illuminate ADHD itself?
Jena: It accentuates the subjectivity inherent in the diagnosis. Mental health diagnoses are distinct from physical health diagnoses. Regulatory bodies treat them differently, as do health insurance providers. The methods of diagnosis vary in some aspects necessarily. With mental health, laboratory tests are not a feasible option. For us, the critical question is how significant is the subjectivity and which factors influence this subjectivity.
What measures should be implemented?
Worsham: A substantial body of literature supports the notion of at least making practitioners aware of potential cognitive biases. In this instance, “Hey, it’s Halloween! You might be perceiving this patient differently compared to other days. Keep that in mind when making a diagnosis.” Just planting this notion could help diminish some of the bias.
Jena: In my publication “Random Acts of Medicine,” we highlighted a finding from a couple of years back indicating that children born in August are more frequently diagnosed with ADHD than those born in September. The rationale is that children with August birthdays in states with a September 1 cutoff for school entry are often the youngest in their class. Thus, their behaviors may differ slightly. The implication is that these students may not actually have ADHD; they merely differ physiologically due to having existed for 20 percent less time than their older classmates.
For physicians diagnosing ADHD, knowing that a child being assessed has an August birthday should prompt a moment of reflection: “Am I making this diagnosis appropriately?”
This sort of information could be easily integrated into electronic health records. When evaluating a child and contemplating a prescription, there are many touchpoints at which the electronic health record could alert you, “Are you aware of this possibility?”
Does this have implications for other neurodevelopmental or psychiatric disorders?
Jena: Broadly, it’s worth considering situations where clinical decisions made by doctors can be swayed by external factors, potentially leading to a greater likelihood of a diagnosis. For example, if an individual visits a doctor’s office and the clinician is deliberating on whether to diagnose them with depression, a recent celebrity suicide or news concerning depression may prompt that doctor to make a diagnosis more frequently due to its prominence in their thoughts.
Worsham: Conversely, this natural experiment is particularly fitting for studying ADHD because Halloween highlights diagnostic criteria for ADHD in ways that do not apply to other disorders, like eating disorders.
The measurements are specific to ADHD, but they suggest we should examine other scenarios, as evidence may exist for other diseases under comparable conditions.
Research referenced in this article was funded by the Agency for Healthcare Research and Quality.