services on release.24 Such benefits, to the extent that they are realised, are contingent on the quality of care in places of detention, and must be sustained after release from detention to result in any long-term health gains. Given that any such health benefits would occur in the context of deprivation of liberty, they would be most appropriately characterised as ‘regrettable’ public health opportunities at best. Understanding the impact of deprivation of liberty on health is complicated by the fact that, as discussed above, it is likely that many children who experience deprivation of liberty are characterised by pre-existing health problems. As such, evidence of a high prevalence of health problems among children deprived of liberty is not, in and of itself, sufficient evidence to infer a causal relationship. Similarly, although evidence of poor health status among young people who have previously been deprived of liberty may indicate that this experience adversely impacted their health, it is also possible that their health was poor before they were deprived of liberty, and that their experience of deprivation of liberty simply failed to adequately address their unmet health needs. This critical methodological issue, which epidemiologists call ‘confounding by indication’, requires careful and rigorous research to unpack. Another complicating factor is that health is not a unitary concept. Although health problems tend to co-occur in marginalised groups, sometimes in a syndemic fashion,25 exposure to deprivation of liberty could conceivably have an adverse impact on some health indicators, and a favourable impact on others. For example, children in justice-related detention may be traumatised by experiences of solitary confinement, assault or other abuses;26 but at the same time benefit from vaccination or treatment for infectious diseases.27 According to the World Health Organization (WHO), health is ‘a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity’.28 A comprehensive understanding of the impact of deprivation of liberty on the health of children and adolescents must consider all of these elements. 24 Joseph C. Gagnon, ‘Making the Right Turn: A Research Update on Improving Transition Outcomes among Youth Involved in the Juvenile Corrections System’, National Collaborative on Workforce and Disability: Research Brief, Issue 3, 2018, pp. 1-28. 25 Marlene M. Eisenberg & Michael B. Blank, ‘The syndemic of the triply diagnosed: HIV positives with mental illness and substance abuse or dependence’, Clin Res HIV/AIDS, Vol. 1, 2014, pp. 1006; Cf. Singer, op. cit., p. 4; Gabriel J. Culbert, Veena Pillai, Joseph Bick, Haider A. Al-Darraji, Jeffrey A. Wickersham, Martin P. Wegman, Alexander R. Bazazi, Enrico Ferro, Michael Copenhaver, Adeeba Kamarulzaman & Frederick L. Altice, ‘Confronting the HIV, Tuberculosis, Addiction, and Incarceration Syndemic in Southeast Asia: Lessons Learned from Malaysia’ Journal of Neuroimmune Pharmacology, Vol. 11(3), 2016, pp. 446-455. 26 Cf. Whitley, op. cit., p. 5. 27 Cf. Templeton, op. cit., p. 5; Belenko, op. cit., p. 5. 28 World Health Organisation, Constitution of the World Health Organisation, 7 April 1948, Available at http://apps.who.int/gb/bd/PDF/ bd47/EN/constitution-en.pdf?ua=1 (accessed 2 August 2019). 121