Five Noncommunicable Diseases (NCD) – diabetes, cardiovascular disease, cancer, chronic respiratory disease and Mental Health Disorders (MHD) – account for 86% deaths and 77% disease burden in the WHO Europe region. Of these five NCDs, MHD is unique as it has a complex bi-directional relationship with the other four major NCDs, meaning that, on one hand, it could be the initiator of the other NCDs, or other NCDs could lead to MHD which, in turn, can further aggravate the primary NCD leading to a vicious circle. Recent research identified MHD as the highest ranked NCD in adolescent population. A specific group in this population that is 3 - 6 times more vulnerable for developing MHD and subsequent NCD is the adolescents diagnosed with Autism Spectrum Disorders (ASD). There is no Evidence Based Intervention (EBI) for preventing MHD in an ASD adolescent since 1) the major risk factors are in-grained in their biological process and 2) they present with multiple MHD comorbidity. Personalisation is the key to prevent their already vulnerable mental states making transition to an MHD - "which" EBI is appropriate for "which" ASD adolescent and "how" to choose it - an unsolved question. Because of their neurobiological characteristics, personalisation must be done at biological level. Recent research showed how the environmental factors can alter gene expressions that leads to an MHD through Epigenetic-Genetic/metabolomic-Mental health (EGM) process. Using quantitative modelling of this process, ETHREAL will develop a personalised, flexible, single service delivery model that will empower an ASD adolescent to self-control their environmental factors while seamlessly accessing the community care services to prevent their mental health making transition to an MHD - a unique solution for sustainable prevention of MHD and subsequent NCDs in this population. Without loss of generality, the proposed solution could be adapted to prevent MHD in wider adolescent population.