The wait time for mental health treatment among adolescents worldwide is a critical period of unmet need that is almost entirely neglected by current service models. In Australia, adolescent help-seekers have reported waiting more than 100 days to access mental health treatment after referral by their General Practitioner (GP). During the wait time, adolescents have significant unmet psychological needs including severe psychological distress, increased use of dangerous and maladaptive coping, and feelings of abandonment. Current wait time offerings across the mental health sector are sparse and lack clear evidence of effectiveness. As such, many adolescents receive minimal targeted care during the wait time and their acute psychological needs remain unmet. This presentation will outline a new service model called While We Wait, which was designed to address the psychological needs of adolescents during the wait time for mental health treatment in Australia using brief digital interventions. Funded by the Australian Government Medical Research Future Fund, this two-year project unites experts in adolescent mental health with GPs and service providers to develop and test a new service model. In 2024, we partnered with expert health service designers from Deloitte Digital Australia to complete a rapid six-week health service design sprint. This iterative industry-led methodology involved a series of weekly activities including the development of service user personas and service experience principles, targeted service user consultation sessions with General Practitioners and adolescent lived experience advisors (aged 18 to 20 years), insight reporting, and service blueprint development. A total of 15 General Practitioners (GPs) took part in the consultation sessions alongside 12 youth experts. advisors. The final service design for the While We Wait service consisted of a 5-stage journey: (1) Recognition of the need for support by the adolescent, (2) Initial consultation and onboarding with the GP, (3) Support and monitoring, (4) Preparation for treatment, (5) Transition and follow-up. The service design was underpinned by five key service principles including “I’m never alone”, “It’s for me”, “I’m in control”, “It’s easy to use”, “It lifts me up”. Critical elements of the While We Wait service design will be presented in this talk, including the optimal integration of digital interventions, including an automated SMS-based program and a digital single-session intervention focussed on growth mindset. This talk will also present an overview of this innovative model as well as the results of the pilot study conducted in Australia with 150 young people and their GPs.