Over the last two decades application of the clinical staging model in mental health has been advocated to improve diagnosis, intervention, prediction of illness trajectory and, ultimately, outcomes. The model offers a substantive advance for mental health care as it goes beyond traditional fixed categories to incorporate a stepwise continuum to guide much more appropriate treatment planning and prognosis. In this chapter, an overview of this advanced type of clinical staging is provided. With its focus on the continuum of mental illness, and underlying differential trajectories of illness progression that are not well captured by current categorical diagnostic practice, staging addresses the key limitations of traditional diagnostic categorical systems. It proposes that effective, safe and timely stage-specific treatments can be implemented to inhibit and delay illness onset and progression. It also enables biomarkers to be analysed according not only to syndrome but also stage. The model is supported by a number of clinical, longitudinal and neurobiological studies. Whilst clinical staging has clear and immediate potential benefits, further research investigating risk and protective factors and treatment outcomes across different stages and the creation of tools that clinicians can routinely use will determine the ultimate utility and value of the model.