By Gemma Buckland

In recent decades, policymakers have become increasingly aware that our legal definition, which treats all people aged 18 years or older as adults, does not reflect the neurological process of maturation. Policymakers across all parts of the criminal justice system have recognised this although changes in practice are variable at best. There is now a considerable body of evidence on the maturation process and best practice in working with young adults (typically defined as those aged between 18 and 25 years old) in contact with the criminal justice system. This review looks at: What we understand about the development of the brain in young adulthood The implications for young adults involved in criminal behaviour The impact of trauma and Adverse Childhood Experiences on the maturation process The “age-crime curve” and the evidence about growing out of crime Implications for best practice working with young adults

London: CLINKS, 2025. 16p.

By The National Institute of Corrections, Justice-Involved Veterans Network.

This white paper is a collaboration between the National Institute of Corrections, the Substance Abuse and Mental Health Services Administration, the U.S. Department of Veterans Affairs, and the National Institute of Corrections-sponsored Justice-Involved Veterans Network. This effort reflects the original Sequential Intercept Model (SIM) that was developed in the early 2000s by Mark Munetz, MD, and Patricia A. Griffin, PhD, along with Henry J. Steadman, PhD, of Policy Research Associates, Inc. The original intent of the Sequential Intercept Model was to “envision a series of ‘points of interception’ or opportunities for an intervention to prevent individuals with mental illness from entering or penetrating deeper into the criminal justice system” (Munetz & Griffin, 2006). The current project builds on prior efforts to adapt (as V-SIM) the original SIM to the justice-involved veterans population challenged by various forms and degrees of mental illness, as well as by substance abuse, and by the trauma from physical injuries (with psychological trauma-overlapping Traumatic Brain Injury of particular note). Each decision point in the criminal justice system represents an opportunity to intercede at the lowest level possible and to minimize the collateral consequences of a veteran getting more deeply involved in the justice system.

Washington, DC: NIC, 2023. 120p.