The results from GWAS showed that common genetic variants, e.g., CHRNA7, CHMP7, NT5C2, RPL13AP3, link with the phenotypes shared in multiple psychiatric disorders, including schizophrenia, bipolar disorder, anxiety, major depressive disorder and ADHD, while none of these genetic variants are robustly associated with ADHD (Franke et al., 2009; Neale et al., 2010; Stergiakouli et al., 2012; Thapar et al., 2012; Cross-Disorder Group of the Psychiatric Genomics Consortium, 2013; Xu et al., 2017; Brainstorm Consortium et al., 2018). Here, CHRNA7 is linked to attention deficit-hyperactivity disorder.