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). Here, HTR1B is linked to attention deficit-hyperactivity disorder.