Ona Davidonienė is the WHO Regional Europe Office partner of the mental health of Lithuania, Lithuanian representative of mental health issues in the European Commission Public Health Program, Lithuanian Republic Parliament Health Committee freelance expert. She is a member of the National Health Board, Lithuanian Association of Psychiatrists, Lithuanian Association of Mental Health Managers, magazines ,,Neuro and mental diseases” and ,,Psychiatry News” editorial board member. Ona Davidonienė participated in the development of major legislation concerning mental health care in Lithuania: Mental Health Strategy 2007, state programs for mental health promotion, mental illness prevention and mental health care. During the 2009 – 2013 Ona Davidonienė led projects funded by the EU: “Child and Adolescent Mental Health in Enlarged European Union: development of effective policies and practices”, CAMHEE); “Health Professional’s Training Program“; „Study of Society Mental Health Risk Factors and Establishment of Trends of Preventive Measures“; „Evaluation of Alcohol Control Policy, Alcohol Damage Assessment“; „Assessment of Mental Health Services Legal Regulation and Optimization of Children Mental Health Services”.