A research scholar of the Institute of Psychiatry (Sydney) and Institute of Psychiatry (UK), A/Professor Jeyasingam obtained his medical degree and psychiatry training in Sydney, then proceeded to have advanced training at the Maudsley in London in Consultation Liaison psychiatry.

A/Prof Jeyasingam holds a double masters in Psychiatry and Business (Health Administration), and is published widely in personality disorders, anxiety and bipolar disorder, in peer reviewed journals and the Sydney Morning Herald. 

A/Prof Jeyasingam is the former Area Clinical Director for the largest mental health service in New South Wales, a Foundation Accredited Member of the Royal Australian and New Zealand Psychotherapy Faculty, a Clinical Associate Professor with Sydney University, and the former Chair of the Faculty of Old Age Psychiatry NSW. He sits on the Committee for Evidence Based Medicine with the College of Psychiatry.