In addition to the coding variants, non-coding single nucleotide polymorphisms (SNPs) (Box 1) in CACNA1C have been found in Genome-Wide Association Studies (GWASs) (Box 1) to be associated with bipolar disorder (BD) [14–17], schizophrenia (SCZ) [18], major depressive disorder (MDD) [19], ASD [20], and attention deficit hyperactivity disorder (ADHD) [21]. The gene discussed is CACNA1C; the disease is attention deficit-hyperactivity disorder.