Dongdong Li, is the Principal Research Specialist at the Translational Social Research Division, the National Council of Social Service (NCSS) in Singapore. Her research involves the study of child protection issues and young offender rehabilitation, such as the predictors and outcomes of involvement in child protection services, effects of childhood maltreatment and the cycle of violence. She has extensive experience in research activities in both academic and government settings in Singapore. She played an instrumental role in several longitudinal studies and has contributed extensively to many international journals, books, and government publications.  Chi Meng Chu, is a clinical and forensic psychologist by training, and a registered psychologist with the Singapore Register of Psychologists and also the Australian Health and Practitioner Regulation Agency. In addition, he is registered with the British Psychological Society as a Chartered Psychologist, Chartered Scientist, and Associate Fellow. Presently, Chi Meng is the Director, and the Senior Principal Clinical and Forensic Psychologist at the Translational Social Research Division, the National Council of Social Service (NCSS) in Singapore. He is concurrently the Director of Strategic Planning Office at NCSS and also the Director (Special Projects) at the Ministry of Social and Family Development (MSF). Chi Meng currently oversees several large longitudinal and multi-birth-cohort studies in Singapore. Chi Meng also had previous stints in forensic mental health and policy settings.David P. Farrington, O.B.E., is Emeritus Professor of Psychological Criminology at Cambridge University. He has received the Stockholm Prize in Criminology and he has been President of the American Society of Criminology. His major research interest is in developmental criminology, and he is Co-Director of the Cambridge Study in Delinquent Development, which is a prospective longitudinal survey of over 400 London males from age 8 to age 61. In addition to 920 published journal articles and book chapters on criminological and psychological topics, he has published 134 books, monographs, and government publications, and 164 shorter publications (total = 1,218).

• Chapter 1. Introduction .- Chapter 2. Methodology of the Longitudinal Study.- Chapter 3. Prevalence and Comorbidity of Emotional and Behavioural Problems of Youths who have Offended in Singapore.- Chapter 4. Prevalence and Trajectories of Depression.- Chapter 5. Drug Use in Youths who have Offended: The Link to Emotional and Behavioural Prob-lems.- Chapter 6. Predicting 2-year Re-Offending Among Youths Under Community Supervision.- Chapter 7. Protective Factors against Emotional and Behavioural Problems in Youths who have Offended.- Chapter 8. Conclusions and Recommendations.