https://www.reddit.com/r/ADHD/comments/1bin00r/professor_stephen_faraone_phd_ama/ > The heritability of ADHD is 70 to 80%. That does not mean that 70 to 80% of those with ADHD have the inherited version it means that that much of their ADHD is due to genetics. We don't know very much about the environmental causes because they are very difficult to study do to problems with confounding. He also mentioned about 7000 genes related to hereditary possibility so that sounds tough 😭