ABSTRACT
Youth mental illnesses are chronic and recurrent and present a continuous disease development and progression, which cause different functional impairments like cognitional, emotional and behavioral disorders.At pre-sent, the clinical diagnosis of youth mental illness largely relies on behavioral symptoms.The diagnosis is made by the consistency between behaviors and symptoms of patients and those described in the diagnostic criteria.Although the diagnosis is operational to a certain extent in clinical practise, its assessment is subjective and lacks effective neurobio-logical indicators, resulting in a low consistency of diagnosis and great challenges in the early diagnosis and standardized intervention of youth mental illnesses.The prodromal symptoms in youth mental illness are unspecific and there is a decrement in neurocognition including social cognition by the emergence of traditional symptom sets.Therefore, transdiagnostic clinical staging model is of great significance in clinical assessment in youth mental illness.Here, the essentials of the " transdiagnostic clinical staging in youth mental health: a first international consensus statement" published in the World Psychiatry in 2020 were interpreted, with a detailed analysis of the key updates, aiming to provide a reference for clinical diagnosis and treatment of youth mental illness.