Dr Crook trained in medicine at Oxford and London Universities qualifying in 1983. He studied psychology at Oxford to understand nonmedical models of the mind. He trained in Psychiatry on the Oxford and Cambridge schemes. Dr Crook has 23 years of full time experience as a practicing consultant in the NHS employed by Norfolk and Suffolk Foundation Trust. He has worked within all aspects of general and old age psychiatry. He has served as the Royal College of Psychiatrists Tutor to train doctors in psychiatry.

Dr Crook has been the Consultant Psychiatrist to the students of the University of East Anglia and Norwich Samaritans. He has been providing medico-legal services since 1993 and in private practice since 2008. Dr Crook is currently a Honorary Consultant Psychiatrist to Norfolk and Suffolk NHS Foundation Trust with duties to train and mentor newly appointed consultants.