Several important and controversial studies have been published in the past few months on ADHD, making the summer research reading all the more fun. Here are summaries of two summer studies for you:
Depressed Dopamine Activity in Caudate and Preliminary Evidence of Limbic Involvement in Adults With ADHD
Some very impressive researchers were involved in this study on ADHD, dopamine, and substance abuse. The researchers included Dr. Nora Volkow who is the Director of the National Institute on Drug Abuse, and Dr. James Swanson from U.C. Irvine. I’ve been a fan of Dr. Swanson’s work on ADHD treatment for many years.
This study concludes that ADHD is a real disease (ed. note: and not just something made up by drug companies to sell meds). ADHD is biologically caused and that dopamine production in individuals with ADHD is decreased, and that Ritalin increases dopamine production.
None of this is particularly new news, but the study is helpful to support this position, which we have held for about twenty years.
The study also reports that because of the lower dopamine levels in ADHD individuals there is a greater risk in the ADHD population for drug abuse, as “drugs of abuse increase dopamine brain function…”
The abstract of the article is available at the ADHD Information Library at http://newideas.net/adhd/adhd_research_5 .
Thank you to the Archives of General Psychiatry, August 2007.
The entire article is made free to readers online at
Gene Predicts Better Outcome as Cortex Normalizes in Teens with ADHD
The lead researcher in this study was Dr Philip Shaw from the NIMH Child Psychiatry Branch. He is an expert researcher on the human brain, especially children’s brains, and researches the structural brain differences in conditions as Schizophrenia and ADHD. Dr. Judith Rapoport was also involved in the study, and she is a long-time researcher in ADHD.
This study showed that there were structural differences in the brains of ADHD children, specifically that the brain areas that control paying attention were thinner in children with ADHD, especially those who carried a particular version of a gene. The good news was that for these particular children, as they reached adolescence, the right side of the cortex normalized in thickness, and performance improved.
So this study is both interested in the genetics of ADHD, and the structural differences in the ADHD brain (vs. non-ADHD). The study is available in full, thanks to the NIMH, at the ADHD Information Library.
There are several more studies from this summer that we will try to summarize for you in the next week or two.