This study is a cluster randomised controlled trial, which aims to examine the short-term strategy of addressing treatment gap through increasing primary mental health service capacity. This study aims to compare after 6 months and 12 months, the effectiveness of a specialist model of mental health care and an enhanced usual care (task-sharing) framework, in terms of reducing mental health symptoms, reducing disability, and improving quality of life, as well as the health services costs (and potentially societal costs) associated with these outcomes in 400 patients.