The idea of developmental transitions and key transition points has been well elaborated in adolescent development literature. Transition points are ideal opportunities for effective intervention because individuals tend to be more open to advice and learning that will assist them (Spooner, Hall, & Lynskey, 2001).

Developmentally appropriate services and programs need to be sensitive to the risks and opportunities inherent in key transitions created by service systems. In relation to treatment of persistent AOD and mental health problems for example, developmentally appropriate programs will incorporate careful transition planning for young people moving from youth specific services to the adult system.

Another service system transition occurs when young people who are child protection clients leave care. Research has shown that many young people lose access to services such as mental health care when they exit child protection (Dworsky & Courtney, 2009; McMillen & Raghavan, 2009). For vulnerable young people who are beginning to develop mental health and or substance use problems a sudden loss of support at this transition point can be devastating.

Transitions from primary school to high school and out of high school are also important periods of change for young people that can influence substance using behaviour.

For young people exposed to multiple risk factors, such as neglect, abuse and poor connection to school, the transitions out of school and out of the Child Protection system may be particularly important windows of opportunity for delivery of early intervention programs.