Simplex schizophrenia is a disorder in which negative states such as paucity of thought, social deficits, emotional indifference, and attention deficits predominate, while some patients also exhibit no obvious positive symptoms such as delusions and hallucinations for more than two years. This type is less common, accounting for about 2% of all schizophrenia. Patients tend to have adolescent onset, insidious onset, not easily detected in the early stages, slow and continuous progression, and poor healing. According to the latest American diagnostic criteria, the typology of schizophrenia has gradually faded. There is less mention of simple schizophrenia and less clinical onset.