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.