1. Introduction Children may be deprived of liberty for a variety of reasons and, although these reasons are often not explicitly related to their health status, it remains likely that those deprived of liberty will be distinguished by a high burden of ill health. This is, in part, because the social and structural drivers of deprivation of liberty overlap with the determinants of health. For example, young people who use alcohol or other drugs may be at increased risk of experiencing justice-related detention for offences related to the behavioural effects of substance use (e.g., disinhibition, aggression), or in relation to criminal charges for drug possession, use, or trafficking.1 Risky substance use in young people is also associated with poor mental health, injury, and infectious disease related to both disinhibited behaviour (e.g., unsafe sex) and injecting drug use.2 Therefore, one might expect children and adolescents in justice-related detention to be at increased risk of poor mental health, injury-related morbidity (including traumatic brain injury; TBI) and infectious disease. Indeed, recent systematic reviews have documented a high prevalence of mental disorder3 and infectious disease4 among justice-involved young people, although to date there has been no overarching review of their health status at the global level. There is also good reason to suspect that children deprived of liberty for other reasons may be at increased risk of poor health. Children in immigration detention often come from settings distinguished by civil and political unrest, or war, and may experience inadequate nutrition, limited access to appropriate healthcare, and/or exposure to environmental risk factors for poor health. Experiences of trauma in their home country and/or during the often arduous journey to immigration detention may have resulted in or compounded mental health problems.5 Similarly, children held in detention in the context of armed conflict or national security may have experienced significant trauma, and may have been injured in conflict.6 In settings of civil unrest and armed conflict, disruption to healthcare 1 Matthew D. Phillips, ‘Assessing the Impact of Drug Use and Drug Selling on Violent Offending in a Panel of Delinquent Youth’, Journal of Drug Issues, Vol. 42(3), 2012, pp. 298-316. 2 Dan I. Lubman, Leanne Hides, Murat Yücel & John W. Toumbourou, ‘Intervening early to reduce developmentally harmful substance use among youth populations’, The Medical Journal of Australia, Vol. 187(7), 2007, pp. S22-26; Fiona M. Gore, Paul J. N. Bloem, George C. Patton, Jane Ferguson, VéroniqueJoseph, Carolyn Coffey, Susan M. Sawyer & Colin D. Mathers, ‘Global burden of disease in young people aged 10-24 years: a systematic analysis’, The Lancet, Vol. 377(9783), 2011. pp. 2093-2102. 3 Seena Fazel, Helen Doll & Niklas Långström, ‘Mental disorders among adolescents in juvenile detention and correctional facilities: a systematic review and metaregression analysis of 25 surveys’, J Am Acad Child Adolesc Psychiatry, Vol. 47(9), 2008, pp. 1010-1019. 4 Stuart A. Kinner, Kathryn Snow, Andrea L. Wirtz, Frederick L. Altice, Chris Beyrer & Kate Dolan, ‘Age-specific global prevalence of hepatitis B, hepatitis C, HIV and tuberculosis among incarcerated people: A systematic review’, Journal of Adolescent Health, Vol. 62(3), 2018, pp. S18-26. 5 Mina Fazel, Ruth V. Reed, Catherine Panter-Brick & Alan Stein, ‘Mental health of displaced and refugee children resettled in high-income countries: risk and protective factors’, The Lancet, Vol. 379(9812), 2012, pp. 266-282; Annette A. M. Gerritsen, Inge Bramsen, Walter Devillé, Loes H. M. van Willigen, Johannes E. Hovens & Henk M. van der Ploeg, ‘Physical and mental health of Afghan, Iranian and Somali asylum seekers and refugees living in the Netherlands’, Social Psychiatry and Psychiatric Epidemiology, Vol. 41(1), 2006, pp. 18-26. 6 John Pearn, ‘Children and war’, Journal of Paediatrics and Child Health, Vol. 39(3), 2003, pp. 166-172. 117