Being diagnosed with ADHD currently requires an interview to assess your symptoms and potentially neuropsychological testing. The result of this diagnostic process depends on how accurately you report your symptoms and the luck of the draw in who your doctor is.
Wouldn’t it be nice if you could just go in for a brain scan that told you with high probability of being correct whether you had ADHD?
One of the points I often see made by people who are in the business of writing articles claiming ADHD is a “fake” disorder is that no such brain scan currently exists. This criticism generalizes to every other mental health condition, as well as some physical health conditions.
These ADHD “skeptics” might be surprised to learn that we’re well on the way to making such a diagnostic brain scan a reality. There is a wealth of research highlighting differences between the brains of people with and without ADHD, and how to integrate these differences into a model that accurately predicts whether people have ADHD is an active area of study.
Most recently, a team of researchers in China presented a model that was able to diagnose participants in their study with 75 percent accuracy. Their technique took advantage of differences in how parts of the brain are connected in people with and without ADHD.
This study is the latest step in our progress toward understanding how ADHD can be identified with a brain scan, but it’s hardly the only promising attempt at predicting ADHD symptoms from brain imaging data.
Previous studies have achieved 90 percent and 93 percent accuracy in samples of 110 and 68 participants respectively. Impressively, a model published in 2015 attained 90 percent accuracy in a sample of 1,177 participants and was able to distinguish between subtypes of ADHD 95 percent of the time. In fact, there are quite a lot of studies that have given exciting results – check out this article in the journal Translational Psychiatry for a more thorough review.
With results like these, you might be wondering: why aren’t we already using brain imaging as a core part of the diagnostic process? Even if it’s “only” 90 percent accurate, surely it could provide a useful data point for clinicians!
There are a few reasons why a brain scan for ADHD is currently a project for research rather than practical use. First, while these models are highly accurate for the groups of people used in the studies, it’s unclear how they would generalize to other people. Before using a diagnostic brain scan as a basis for medical treatment, it would need to be tested on quite a lot of people with different demographic characteristics.
Second, even if these models work as well as the results suggest, it’s an open question why they work. We know that people with and without ADHD have certain patterns of brain differences, but understanding how these brain differences give rise to ADHD symptoms is a long-term project. These models are evidently seeing something relevant to the diagnostic process, but the fact that we aren’t sure exactly what they’re seeing naturally makes us more cautious about using them in the real world.
Finally, there are financial barriers preventing these models from becoming widespread in clinical practice. If you’re going to diagnose someone using a brain scan, you need to actually have a scanner! Your friendly neighborhood psychiatrist probably doesn’t have an MRI machine tucked away in the back room. It turns out one of the main reasons we don’t have a brain scan for diagnosing ADHD has less to do with our understanding of ADHD and more to do with economics.
Despite these obstacles, we’re probably heading toward an era when “objective” measures of brain functioning do become a key element of the diagnostic process. When you look at how much brain imaging and machine learning has developed in, say, the last twenty years, it’s not unreasonable to think that we’re in striking distance of something as futuristic as a brain scan for ADHD.
When that happens, I’m going to celebrate. Partly because it’ll likely make the diagnostic process easier and more accurate for people with ADHD, and partly because I finally won’t have to read any more articles about how ADHD just has to be a “made-up” condition since there’s no brain scan for the disorder.
Image: Flickr/Ars Electronica