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Clin Asst Prof Ong Pui Sim

Clin Asst Prof Ong Pui Sim

MBBS (Spore), MMed (Psychiatry)

Senior Consultant

Specialty: Psychological Medicine

Conditions Treated by this Doctor:
General Psychiatry, Geriatric Psychiatry, Narcolepsy​, Sleep Disorders.

Clinical Appointments

  • Senior Consultant SingHealth Duke-NUS Centre of Memory and Cognitive Disorders
  • Senior Consultant SingHealth Duke-NUS Sleep Centre
  • Senior Consultant Psychological Medicine Changi General HospitalChangi General Hospital
  • Deputy Director (Clinical) Sleep Medicine, Surgery & Science Changi General HospitalChangi General Hospital
  • Senior Consultant Sleep Medicine, Surgery & Science Changi General HospitalChangi General Hospital


Dr Ong Pui Sim is a senior consultant with the Department of Psychological Medicine at Changi General Hospital (CGH). She is also the director of Geriatric Psychiatry Service and deputy director of the Community Psychogeriatric Programme in CGH. She received her medical degree from the National University of Singapore in 1984 and received her specialist training at Institute of Mental Health.

Dr Ong had overseas clinical attachment in the field of psychogeriatrics in Sydney, Australia as well as in sleep disorders in Stanford Sleep Disorder Centre, USA. She is actively involved in undergraduate and postgraduate medical teaching with National University of Singapore and Duke-NUS. She is also on the management committee of Alzheimer’s Disease Association and Bethel Community Services.


  • MMed (Psychiatry)
  • MBBS (Spore)

Professional Appointments and Committee Memberships

  • Clinical Assistant Professor - Duke-NUS Medical School
  • Clinical Lecturer - Yong Loo Lin School of Medicine, NUS
  • Physician Faculty Member - National Healthcare Group (NHG) Residency
  • Director - Geriatric Psychiatric Service, Psychological Medicine Department, CGH
  • Assistant Director - Sleep Medicine, Surgery & Science, CGH
  • Member - Medical Ethics Committee, CGH
  • National Transplant Ethics Panel, MOH
  • Singapore Medical Council’s Complaints Panel
  • Member - Tribunal for Maintenance of Parents, MSF
  • Medical Specialist Panel of Work Injury Compensation Medical Board, MOM


  • National Council of Social Service, Long Service Award - 2016
  • MOH Long Service Award - 2015
  • National Day Awards, Long Service Medal - 2014

Research Interests


• Late-life Depression: Current Issues and new Challenges, Ann Acad Med Singapore 2003; 32:764-70

• Psychogeriatric Services in Singapore, ASEAN Journal of Psychiatry, Vol 6, No.1 Dec 2003

• Validation and Comparison of Three Brief Depression Scales in an Elderly Chinese Population, Int. J of Geriatric Psychiatry 15, 824-830 (2000)

Research Trials

• Randomised, double-blind, placebo-controlled, parallel-group, 12-month trial of leuco-methylthioninium bis (bydromethanesulfonate) in subjects with mild to moderate alzhiemer’s disease- principal investigator (Dept of Psy Med, CGH) from Dec 2013 to Jun 2015

• An exploratory placebo-controlled, dose-ranging study of the effects of methythioninium chloride 30 mg tid, 60 mg tid and 100 mg tid in patients with mild to moderate dementia of alzheimer type, co-investigator, 2007 to 2009

• National community mental health prevalence study of depression, anxiety and dementia in the elderly, co-investigator, 2003 to 2004