ADHD

Is ADHD Genetically Influenced? Yes!

Genetics influencing ADHD as "neuroscience fiction"? Seriously?

Posted Mar 19, 2015

I wanted to just let this one go and take a deep breath, but this post by Dr. Wedge, which will undoubtedly be read by a large number of people, is just so factually inaccurate and misleading that I can’t in good faith ignore it.

Please be aware that the reason that the vast majority of scientists and scholars believe that ADHD has a large (although certainly not exclusive) genetic component is not from a single study done in 2010 as the post implies but rather from dozens of studies across decades from around the world and performed mainly in twins. The bottom line of these studies is this: the levels of ADHD behaviors are much more similar between identical twins (who share all of their DNA) than between fraternal twins (who share—on average—half their genes). And remember, these are twins living in the same household with the same parents and with much of the same environment.

While the exact calculated magnitude of the genetic influence is different from study to study, it is always found to be there and usually found to be very large (in some cases, on par with the genetic influence for height). Twin studies are not perfect (no study is) and contain some assumptions that can be challenged, yet for Dr. Wedge simply to pretend that this vast amount of research doesn’t exist really boggles the mind. Nobody in 2015 argues that ADHD is due only to genetics and to write a post against that position is the classic straw-man argument. 

It is true that scientists have not been able to find “the gene” for ADHD on a molecular level, but that is likely because there are so many genes involved in brain processes as complicated as those that underlie behaviors related to attention, impulse control, and activity level. Using the analogy from the last paragraph, nobody has found “the gene” for height either, yet there are no blogs about how height isn’t real or isn’t genetically influenced. Nobody has found a specific test or gene for even our most severe cases of autism either, but the importance of genetics in autism is indisputable.

Even the article she cites as evidence for ADHD's not being genetic doesn’t actually say this (please read it yourself, as it is free). It is the epitome of irony that Dr. Wedge invokes a study that calls out the misrepresentation of scientific data and then distorts the study’s conclusions beyond recognition. 

There are legitimate debates about ADHD that are and should be discussed. The public, however, deserves much better than this. 

@copyright by David Rettew, M.D.

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