Duddle studied medicine at the University of Manchester, where she qualifed in 1944 and took a DPM in 1960. She was a consultant psychiatrist at Cheadle Royal Hospital, Cheshire, and a pyschiatric adviser to the student health service at the University of Manchester. Duddle became a fellow of the Royal College of Psychiatrists in 1977. Two of her children (Judith Ann and David Owen) were general practitioners. Duddle married in 1944 but continued to practice under her maiden name.