A sharp increase in children’s behaviour problems in the 1960s and ‘70s was noted by two U.S. paediatricians who reported their findings in medical journals. Dr W. Crook described why he became interested in this problem: “In my general paediatric practice in Jackson Tennessee (pop 50,000) in the 1950s, my partners and I were ‘the only game in town’. Yet we only saw an occasional hyperactive kid ... In the 1970s, I saw so many hyperactive children that I kept records...“