Previous research has demonstrated that while 75% of patients respond to any stimulant, of those who do not 33% will respond to a stimulant of the other class. Based on previous research correlating increased mutations in the dopamine system genes DRD1, 2, 4, 5, dopamine transporter, COMT, and MAOA with ADHD, we will also be investigating the relationship between mutations in these genes and patient response to MPH and amphetamines. This study is a pilot, but it was an obvious next step in the studies that are being done on the genetics of ADHD. The outcome of this research, whether an association is or is not found, will be of considerable interest to researchers internationally, and will demonstrate the value of HELP funding in promoting research that can alleviate mental illness in children The study will make a significant contribution to appropriate intervention for these children, and promote greater awareness that the deficits suffered by children with attention problems is neither willful nor a matter of intelligence, but rather a syndrome that can be explained and can be modified with appropriate medical care.

A chi-square test will be conducted to determine whether there is differential representation of SNAP 25 among therapeutic methylphenidate responders versus non-responders. Statistical comparison will be performed using a two-tailed test at the .05 level of significance.