Simon studied Psychology and Medicine at the University of Leeds, before training in Psychiatry and Health Services Research. He held a four year MRC fellowship, and gained his PhD from the University of York in 2000.
His main area of research interests is the management of common mental health problems in primary care, and he has published widely on the value of screening strategies and case management for depression.
Simon collaborates with colleagues from the Universities of Manchester, Leeds, Sheffield and Bristol on an MRC-funded trial of enhanced care for depression. He is principal investigator on the largest ever trial of computer-delivered Cognitive Behaviour Therapy for Depression – funded by the Health Technology Assessment Programme. 
In addition to clinical trials, his methodological interests are in various forms of evidence synthesis, including meta-analysis and decision modelling. Simon is Editor for the Cochrane Depression and Anxiety Group, and Associate Editor of both the British Journal of Clinical Psychology & the British Journal of Psychiatry.
Simon joined HYMS in 2005 and contributes to teaching in psychological medicine, psychiatry, population health and evidence based decision making.
Simon holds a joint appointment with the Department of Health Sciences, University of York.