Paul has been involving in suicide prevention research and mental health promotion and practice since 2003. His recent research projects include social withdrawal behaviour (a.k.a. hikikomori), using animals as part of psychological and educational interventions, and youth positive development interventions for local and non-Chinese in Hong Kong. He is currently an Honorary Fellow of the Centre for Suicide Research and Prevention HKU, HK Police College, Council Member of the Hong Kong Psychological Society; and was National Representative of the International Association for Suicide Prevention (2010-2015). He is Programme Director of the B.Soc.Sci (Counselling) and Deputy Director of M.Soc.Sci. (Counselling). He has published more than 70 academic articles on a number of suicide-related, and mental-health-related issues, developer of award-winning website (www.depression.edu.hk) and book author of “留給最愛的說話/The Belated Dialogues between the Suicides and Their Families”.