APPLAUSE’s aim is to produce a body of evidence that illustrates how young people with mental health problems currently interact with both formal mental health services and informal social and familial support structures. Careful analysis of data gathered in the UK and Brazil will allow formulation of globally relevant insights into mental health care delivery for young people, which will be presented internationally as a resource for future health care service design.APPLAUSE will allow the collection of an important data set that does not currently exist in this field, and will look to other disciplines for innovative approaches to data analysis. Whist standard analysis may allow for snapshots of health service use, using innovative life course methods will allow us to to characterise patterns of complete service use of each individual participant’s experience of accessing mental health care and social support.Adolescence is a critical period in mental health development, which has been largely neglected by public health efforts. Psychiatric disorders rank as the primary cause of disability among individuals aged 10-24 years, worldwide. Moreover, many health risk behaviours emerge during adolescence and 70% of adult psychiatric disorders are preceded by mental health problems during adolescent years. However, delays to receiving care for psychiatric disorders, following disorder onset, avreage more than ten years and little is known about factors which impede access to and continuity of care among young people with mental health problems. APPLAUSE will analyse current access models, reports of individual experiences of positive and negative interactions with health care services and the culturally embedded social factors that impact on such access. Addressing this complex problem from a global perspective will advance the development of a more diverse and innovative set of strategies for improving earlier access to care.