Our genetics likely contributes significantly to the way we respond to medicine. If there was one single genetic picture for people with Inattentive ADHD, we could probably all be put on the exact same medicine and we would all do beautifully. Alas, this is not the case and people with Inattentive ADHD differ in their gene profiles and they will also differ in their response to the different medicines used to treat ADHD.
The Journal of the American Academy of Child and Adolescent Psychiatry is about to publish another study that looked at why some people with ADHD respond well to Ritalin while others do not. This study looked at specific genes and concluded that if you had a certain type of DRD4 gene or a certain type of DAT gene then your ADHD hyperactive-impulsive symptoms would improve on Ritalin but if you had another type of these genes, there would be less of an improvement.
This study did look at inattention but it does not appear from a discussion of their findings that there was any difference in Ritalin's affect on inattention related to genes. This may have been because Ritalins improves hyperactivity and impulsive behavior more than it improves attention or it might be because the genetics of ADHD-PI is thorny. There is not one gene that identifies the sub-types and there is not one sub-type of the genes that predicts symptoms or treatment response.
There are a couple of questions in the forum that could use answers from you. I have purposely stayed quiet in the forum as you can find what I think here in the blog. I would like others, like you, to voice what has helped you or your family on the Primarily Inattentive ADD Forum . Thanks in advance for helping!!
Am Acad Child Adolesc Psychiatry. 2011 Nov;50(11):1129-1139.e2. Epub 2011 Sep 15.
Pharmacogenetic predictors of methylphenidate dose-response inattention-deficit/hyperactivity disorder.