Going beyond the classroom: The science of ADHD and how it impacts your learners
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Is it food additives? Is it TV? Is it our phones? Actually, the causes of ADHD are mostly genetic, meaning passed down from parents, and sometimes environmental. In fact, as our technology has grown more sophisticated, we’ve actually found that the causes of ADHD are more complex than we previously thought. Conservative estimates for the global prevalence of ADHD indicate that one in 12 children and one in 14 adults have ADHD (Ayano et al., 2023), and studies suggest that the actual rate is even higher, meaning our classrooms almost certainly have students with ADHD, whether they know it or not. Understanding that the root causes of ADHD are mostly down to genetics—something beyond our students’ control—means that teaching with empathy and flexibility should be our number one priority to ensure that we meet all students where they are.
Causes and risk factors
Different scientific studies put the estimated heritability of ADHD at around 70 – 75%, which means that 70-75% of the ADHD identifications (or diagnoses) in the population are down to genetics and the rest of the cases can be attributed to the environment and other factors (Thapar et al., 2012). This means that a child with ADHD most likely has a parent with it, too. That being said, researchers haven’t been able to consistently pinpoint which genes are the so-called “ADHD genes,” but they think this could be possible in the future with more studies (Sonuga-Barke et al., 2023).
“70-75% of the ADHD identifications (or diagnoses) in the population are down to genetics.” Thaper et al., 2021
So, the other 25 – 30% that causes ADHD—is it food additives? Red dye? Added sugars? First, in terms of environment we need to distinguish between risk factors (which show correlation) and mechanistic factors (which show causation). When looking at a student’s poor writing performance, for example, there are several factors that might affect the outcome: the student isn’t interested in the topic, the classroom is noisy, and they didn’t sleep well the night before. These could be considered risk factors—they don’t cause the problem, but they might make it more likely for something to go wrong. Mechanistic factors, on the other hand, would be that the student doesn’t know how to write a clear thesis statement, or what the difference between an analysis and a summary is. These issues directly contributed to the student’s poor performance, compounded, perhaps, by the risk factors mentioned.
OK, so now that we know the difference between risk factors and mechanistic factors, can we finally find out if it’s those pesky food dyes? Drumroll please…! No studies have found a causal link between food additives and ADHD. There was one study from 2012 which found that 8% of children already identified as having ADHD may experience more extreme symptoms related to food colors, but they did not cause the ADHD. Another older study found that food colors and preservatives increased hyperactivity in young children, but—again—no causal link was found and certainly no ADHD as a result.
Well, if it’s not food additives, then what is meant by environmental factors? A recent large meta-study, a type of study which summarizes lots of smaller studies to get an overview, identified nine environmental associations—meaning risk factors—as having what they called “high credibility.” Most of them had to do with maternal factors during pregnancy such as: being overweight in pregnancy, high blood pressure in pregnancy, preeclampsia, acetaminophen or paracetamol use, and smoking. They also identified two factors based on the child themselves: low vitamin D and childhood eczema. While these studies showed some promising results, the effects were pretty small. We also can't say for sure that one thing caused the other, so it's best not to overstate these findings. Other studies show tentative results regarding air pollution as a potential factor, as well as low birth weight and extreme institutional neglect. However, just like we can’t pinpoint a single gene which causes ADHD, we still have a ways to go before we can accurately identify environmental causes.
The impact on our classroom
Understanding the “why” behind our learners’ behaviors is key to creating an inclusive classroom environment. The way our students with ADHD act is not a behavioral choice, it is a direct result of differences in brain function. So perhaps instead of feeling frustrated at a student who still hasn’t started on the classroom task you assigned 5 minutes ago, ask yourself what else could be going on. Our learners with ADHD may struggle with:
- Paying attention for longer periods of time
- Keeping their body still or keeping their mind focused and calm
- Waiting for their turn to speak
- Staying organized both physically and mentally
- Prioritizing tasks and deciding where to start
- Listening and processing spoken instructions
- and emotional regulation.
“Try writing the instructions on the board or putting them up on the screen so that they can be referred to at any time.”
Knowing this, you think back to when you gave your class the instructions for the current task. You said “Work with a partner and brainstorm ideas for your final presentation. You have 15 minutes to come up with at least five different ideas.”Seems straightforward enough, but often giving instructions in just one mode can be insufficient. The learners who missed the instructions won’t realize until it’s too late to ask without getting into trouble, and even those who did listen may find it difficult to keep important information in their working memory, so they have since forgotten. You could approach the student who hasn’t started yet and repeat the instructions, but this could lead to a feeling of stigma. Instead, you could try writing the instructions on the board or putting them up on the screen so that they can be referred to at any time. A bonus of this method is that you would also be supporting any others who missed the instructions for whatever reason—perhaps they’d stepped out to the bathroom for moment or were busy digging through their bag looking for a pen. When we structure our teaching to support the most vulnerable, we end up helping all of our learners. The Advancing Learning for Everyone page is a great place to start on this journey!
The positive side
Even though this blog post talks about the causes of ADHD and advances in this type of research, we do not simply see ADHD as a disorder in need of a cure. While ADHD impairment can range from mild to severe depending on the person and the day, the differences in the brain’s wiring can also offer strengths. People with ADHD are able to hyperfocus when something piques their interest, often staying on one task or topic for hours, days, even months. Though there’s not much research on the positive sides of ADHD yet, initial studies show that people with ADHD tend to be more flexible in terms of planning and last-minute changes, as well as being more emotionally sensitive and attuned to others’ feelings (Sedgwick et al., 2019). So while we don’t believe ADHD is something to be cured, perhaps a better understanding of it could lead to more effective management of those symptoms which cause impairment, allowing the strengths to flourish.