Table 3 summarises eight studies that focused on neurodevelopment: typical development; the impact of early life stress on young adulthood; BDNF polymorphism in early life; ADHD; preterm brain injury; hippocampal sclerosis in mesial temporal lobe epilepsy; birthweight discordance between twins and its impact on cortical anatomy. This evidence concerns the gene BDNF and attention deficit-hyperactivity disorder.