Finally, genome-wide association studies revealed a link between expression of Notch1, that was downregulated in stressed Tph2+/− mutants, and the incidence of epilepsy (Huan et al. 2017) and ADHD (Alemany et al. 2016) that again might be interpreted as a manifestation of dysregulated brain inhibitory processes, a mechanism closely related to excessive aggression. The gene discussed is TPH2; the disease is attention deficit-hyperactivity disorder.