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2 for 1: Recent Research on ADHD & Why "Research" is Confusing


24Sep 2010

I have two interrelated issues to discuss this week. First, there has been some significant research come out on ADHD & ADD individuals recently that will be helpful to know about. Secondly, I want to talk about “research” and why it is so confusing to understand (and how the mainstream media screws up our thinking so much in how they report the results.)

Some context. I am trained in doing research. I have published research in relatively high level journals. I review and interpret research. But, just like most people, I am skeptical when I hear “researchers have found that …” because often we hear contradictory results reported (drink milk to lose weight / don’t drink too much milk) or later, we find out the research didn’t mean what we were told. Having said that, let me clarify some of the issues. (It looks like I am going to have to deal with the second topic [confusion about research] first.)

Most “research” as we know it today involves comparisons of groups of people. People who received a treatment or intervention, in comparison to a similar group of people who did not receive the treatment (but maybe received a fake treatment — called a placebo.) So, for example, we may compare one group of 8 to 12 year old boys diagnosed with ADHD to another similar group who receives an intervention. We then compare the results between the groups.
There are clearly benefits of group-based research — that is why they do it. The research typically is more powerful in eliminating individual differences that could contaminate the results.

The problem is: the research results have to do with groups of people, not individuals. For example, we can clearly say that for boys who are truly ADHD and have fairly severe symptoms (hyperactivity, impulsivity, short attention span, distractibility), treatment by medication often helps these individuals. Not always. Meds don’t help everyone.

Conversely, research of groups of ADHD individuals finds that for groups of these people, treating food allergies doesn’t change their behavior significantly. However, there are clearly some individuals who have been helped by treating food allergies and their ADHD symptoms decrease.

So, eventually, interpreting classic group-based research involves a “cost/benefit” analysis. If only 1 out of 50 ADHD boys is found to have significant food allergies that impact their behavior (I’m making up the number here), is it worth going that route? It depends on the family and their value system. Or, if 9 out of 10 true ADHD students with moderate to severe symptoms are found to be helped by medication, should you go that route? (This is a true number.) Again, it depends on the family and their value system — and what risks they think are associated with the medication.

So here is some recent research on ADHD, that appears to be valid for groups of individuals:

1. Boys with ADHD show good levels of attentive behavior on tasks that do not require working memory. (Working memory is remembering information while using it.) But when working memory is required, their on-task behavior declines significantly. This is the first research that purports to demonstrate a functional relationship between working memory and attentive behavior.

The importance? The findings may explain why boys with ADHD show a lot of variation in their ability to stay focused on different types of tasks. When tasks require a lot of working memory (multiple step instructions, reading comprehension, multiple step math problems, for example), then their focus and attention decline significantly.

2. Adolescents with more “Western” culture diets (fast food, red meat, processed meat, high fat dairy products, potato chips, & soft drinks) were twice as likely to be diagnosed with ADHD than those whose diet were low with these items.

CAUTION: We CANNOT yet say that the foods in the ‘western’ diet CAUSE ADHD. It could be that adolescents with ADHD are more likely to crave and eat these foods than non-ADHD students. So be careful and don’t overinterpret these findings.

3. Recent research cited in the scientifically acclaimed Parade magazine (found in Sunday newspapers – I”m being sarcastic here) suggests exposure to pesticides may increase the incidence of ADHD — but two studies found differing results, one supporting the conclusion, the other didn’t. (Why cite the research? It smacks of a political agenda.) And another study is cited that suggests ADHD may be overdiagnosed — because we are expecting too much from young students.

I do believe ADHD is overdiagnosed, and that medications are overused. And I agree that often our expectations for 5, 6 & 7 year old boys are unrealistic (sitting and doing seat work in school for several hours.)

But the “research” isn’t really conclusive yet. That is often a problem — the media reports research results that aren’t substantiated over time.

One point to remember: a single study doesn’t mean the findings are fact. Usually, multiple studies need to be done with different groups and in different settings. (To be honest, that is why the research with the Cogmed working memory training is so impressive — multiple studies, multiple age groups, multiple cultures – and they are consistently finding that the training has positive effect for most [not all] trainees.]

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