ADHD is one of the most prevalent, and heritable behavioural disorders in childhood. Genetic associations have been reported with polymorphic variants within or near to dopamine pathway genes. Recently snap-25 has also shown association with ADHD in several datasets. We therefore investigated other genes that produce proteins that interact with SNAP-25 in the mechanism of vesicular release of neurotransmitters at the synapse. A total of 106 SNPs were screened for minor allele frequency greater than 5% and 61 SNPs selected for analysis in DNA pools made up from an ADHD clinical sample of DSM-IV combined type probands (n = 180) and a control sample of 90 males and 90 females. Initial screening identified several SNPs that showed allele frequency differences of 5% or more. One SNP in the synaptophysin gene showed suggestive evidence of association following case-control and TDT analysis and warrants further investigation.