Lost & Found Sound 'Mental Hygiene' Films November 12, 1999 • As many as 3,000 "mental hygiene" films were shown in schools in the years after the Second World War. They provide lessons about dating, manners and delinquency, all wrapped up in a tidy 10-minute package. Lost and Found Sound got a tour through these films from author Ken Smith. 'Mental Hygiene' Films Audio will be available later today.