Sean A Spence is Professor of General Adult Psychiatry at the University of Sheffield and Honorary Consultant Psychiatrist in Sheffield Health and Social Care Trust, where he is consultant to the Homeless Assessment and Support Team. He has previously held a De Witt-Wallace visiting research fellowship at Cornell University, New York (1999) and a MRC Clinical Training Fellowship on the MRC Cyclotron Unit, Hammersmith Hospital (1995 - 1998) while contemporaneously Honorary Lecturer in Psychiatry at Imperial College School of Medicine, London. In 1997 he was awarded both the Royal College of Psychiatrists Research Prize and Medal and the Royal Society of Medicine Section of Psychiatry Essay Prize. His principal research interest is in the regulation of voluntary behaviour (volition) in healthy people and those affected by neuropsychiatric disease. His clinical interests include the psychiatric care of the homeless and the socially marginalised.