BSc Manch 1952, MB ChB 1954, DCH 1959, DRCOG 1962; MRCP 1970.
Casson was born on 15 August 1931 and was educated at Manchester Grammar School and the University of Manchester. After qualifying, Casson held junior positions at Crumpsall Hospital Manchester, MRI and Booth Hall Hospital Manchester. From 1960 Casson was a private general practitioner in Didsbury. He was a member of Manchester Medical Society and was president of the Section of General Practice in 1980.