The clinical staging model is an approach used in medicine to define the extent of disease. In psychiatry, this model has recently been applied to psychotic disorders to distinguish the earlier, non-specific features of illness (e.g. ultra-high risk [UHR]; at-risk mental state [ARMS]), from later, more severe features associated with chronic illness. A key element of the staging model is to identify and classify the neurobiological processes underlying the disorder and to define potential interventions in the different stages. With the premise that dysfunctional neural mechanisms underlie symptomatology, the integration of categorical phenotypic classifications (class of disorder) with dimensional criteria (domains of dysfunction) becomes crucial. This approach aims to better classify trans-diagnostic dimensions of disease and discrete symptom-specific subgroup populations within biological frameworks, which may lead to the detection of new biomarkers and the development of more effective treatment and prevention strategies.