He undertook his higher specialist training at St Christopher’s Hospice, London and held the post of Consultant Physician at St Christopher’s before returning to Ireland in 1991.
Professor O’Brien has served as chairperson of the National Advisory Committee on Palliative Care, the National Council for Specialist Palliative Care, the Irish Association for Palliative Care and the Council of Europe Expert Committee on Palliative Care.
He previously served on the executive of the Association for Palliative Medicine of Great Britain & Ireland and currently is chairperson of the European Pain Federation (EFIC) opioid expert committee and board member of the All Ireland Institute for Hospice & Palliative Care.
Prof O’Brien chaired the HPRA expert working group on ‘Cannabis for Medical Use – a Scientific Review’ which was established by the Minister for Health. He has published and lectured widely on various aspects of palliative care policy, pain and symptom management. He has a particular interest in ethical and legal issues at the end of life.