Some really interesting stuff!

If you've ever wondered which genes are tied to or associated with ADD or ADHD, check out this link below:

http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=143465

"New findings suggest that attention deficit and hyperactivity disorder (ADHD) is the most common behavioral variant associated with a mental condition. ADHD prevalence reaches figures of 18% in populations worldwide."

18 percent (http://www.ncbi.nlm.nih.gov/pubmed/17467976?ordinalpos=6&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)? And that's the NIH talkin'! Woah, sounds like we need to get some more visitors to this forum!

We usually hear that ADD and ADHD cases are typically found in only about 5% of the population in the westernized world and even lower world-wide.

Is anyone familiar with Thom Hartmann's Hunter-Farmer Theory?

Check out this link (http://www.ncbi.nlm.nih.gov/pubmed/17467976?ordinalpos=6&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum) on the prevalence of ADD and ADHD worldwide!

Just a bit more info on ADHD genes, in case anyone is interested.

I found a summary of an article (http://www.nature.com/mp/journal/v11/n10/abs/4001869a.html) from a couple of years ago that did a summary-report on 51 different genes thought to be associated with ADHD based on a compilation of recent studies. They found that 18 of them actually have a statistical bearing on the development of the disorder, with 8 being significant with regards to developing ADHD.

So much for ADHD just being "all in your head", right? Cool stuff!

You can check out a summary of the results and the names of the "ADHD genes" here (http://www.nature.com/mp/journal/v11/n10/abs/4001869a.html).

Good stuff!

ADHD is caused by the 7-repeat allele of the DRD4 (dopamine receptor D4). I read that this variant was more common in Africa and South America, probably because farming developed later on these continents and ADHD still conferred some advantages for survival among nomads.

Africa and South America being two of the fastest growing regions on earth (population-wise), the percentage of people with ADHD can only increase over the years. I don't care if it is common or not though.

ADHD is caused by the 7-repeat allele of the DRD4 (dopamine receptor D4). I read that this variant was more common in Africa and South America, probably because farming developed later on these continents and ADHD still conferred some advantages for survival among nomads.

I would say that some cases of ADHD may be in part due to differences in dopamine signalling, including differences in the D4 dopamine receptor. The DRD4 gene seems most linked to increases in novelty/sensation seeking, and therefore may be more linked to ADHD with hyperactivity or comorbit substance abuse than ADHD without hyperactivity.

I cant remember the details but theres two genetic markers that identify how someone will respond to dopamine. They tested this by administering amphetamine and giving people various mental tasks. This is probably instrumental in how ADHD effects people differently.