reported significant associations for DAT1, DRD4, DRD5, 5HTT, HTR1B, and SNAP25, but also significant heterogeneity for the associations between ADHD and DAT1, DRD4, DRD5, DBH, ADRA2A, 5HTT, TPH2, MAOA, and SNAP25 (88). This evidence concerns the gene SLC6A3 and attention deficit-hyperactivity disorder.