When it comes down to it, scientific studies are the best resource we have for learning about ADHD. And it’s easy enough to find research being done on ADHD – just go to a database like Google Scholar or PubMed and type in “ADHD,” then filter the results as you wish.
It’s important to keep in mind that not all scientific studies are created equal, though. When you’re reading about studies on ADHD either directly or through media articles, here are five questions to ask.
Often, the authors of a study or the journalists writing about it give the study a catchy interpretation.
Here’s a hypothetical example: some researchers do a study finding that people with ADHD watch more TV. Then newspapers rush to put out articles declaring that watching TV causes ADHD.
Just because two things are related doesn’t mean one definitely causes the other. Correlation and causation are not the same.
In this example, what the study actually found is that people with ADHD watch more TV than people without ADHD. The study doesn’t address which one causes the other.
It could be that watching TV makes people’s ADHD symptoms more severe. It could also be that people with ADHD end up watching more TV because of issues with impulsivity and time management, or maybe they’re more likely to be unemployed and people who are unemployed watch more TV. It might be that neither one causes the other – that there’s some other factor the researchers didn’t explore that makes people more likely to have ADHD and more likely to spend a lot of time watching TV.
Always keep in mind in concrete terms what the study showed, and be skeptical of interpretations that go beyond that.
2. How many people were in the study?
A basic fact to know is how many people participated in the study. A study that found a pattern in 10 people and a study that found the same pattern in 1,000 people are two different things.
3. How strong was the effect?
You’ll frequently hear researchers talk about a study having a “significant” result. Essentially what that means is that they found a pattern that probably (but not definitely) isn’t a result of pure chance.
Even if the result was “significant,” that doesn’t say anything about how strong the pattern was.
Let’s go back to the example of a study showing that people with ADHD spend more time watching TV than people without ADHD. How much more, though? If it’s 10 minutes more per day, that’s different than if it’s 2 hours more per day.
Sometimes the researchers who did a study will emphasize how big (or small) the effect size is, and other times you’ll have to dig into the statistics in the “Results” section of the paper to find out, which you may or may not want to do.
In any case, it’s worth keeping in mind that a “significant” effect can still be tiny, and that no matter how big the effect size is, it says something about the average traits of a group, not necessarily about any one individual.
4. What do other studies say?
At the end of the day, one study by itself can only tell you so much. More useful is when a pattern shows up in multiple studies. So when you come across an interesting study, it can be helpful to find out whether other studies have come to similar conclusions or have been able to replicate the result.
A special type of study that’s worth paying attention to is a systematic review or meta-analysis. This is a study that looks at previously published studies on a particular topic to see if there’s an overarching pattern. This type of study is useful for understanding what the research says in aggregate.
It can take a little work to hone the ability to read a study on ADHD. However, it’s worth it to be able to evaluate independently what the research on the disorder actually says. If you have any other tips for interpreting studies on ADHD, please leave a comment below!
Image: Flickr/Geoff Hutchinson