With the formal retraction of a 1998 paper claiming ADHD was chemical in origin, related specifically to mercury in kids' vaccines, it may surprise you to know that research into this and related conditions, like Asperger's Syndrome, is still focused on chemistry rather than genetics.
I have long had a personal stake in this. I was diagnosed with ADHD in 1964, my son in 1997. I learned of my diagnosis that same year. A few years ago I described it as like having Robin Williams (right) in your head.
Williams' brilliance, and that of other ADHD sufferers, is exceeded only by that of the Asperger's Syndrome cohort, which is now said to include Albert Einstein. If you have these conditions in your family, in other words, you may have a hard road, but at least it's brightly lit.
Instead of linking the ADHD spectrum to mercury in vaccines, as Andrew Wakefield did, the new culprit is lead in paint. Among kids susceptible to the condition, it is thought, lead in old paint could be a trigger.
Chemistry is not just the suspect in causing ADHD, but in tracing it and, perhaps treating it. While current approaches focus on syncing mind to body by speeding-up the body -- Ritalin and Adderall are stimulants -- new research is focusing on stress hormones like cortisol, newly implicated in Asperger's, and on other stress hormones.
Synchronizing medication to the body's rhythms would dramatically change treatment. But timing a drug to the rhythms of daily life, and expected stress, will be difficult.
So how are our hormones getting out of whack? New research into brain structure may provide an answer.
Now researchers in Spain and Israel have isolated that part of the brain, which governs the risk-reward system, that is underdeveloped in ADHD kids.
What this tells me is that while science does make mistakes, and scientists do as well, trends move in one direction. When it comes to ADHD and Asperger's (which I like to call graduate-level ADHD) that direction is chemical.