It is now generally accepted that schizophrenia is preceded by a prodromal phase, in which a range of subclinical symptoms, including perception, thinking, speech, and behavior, are present. Although a growing number of researchers have focused on this phase, no definitive diagnosis is proposed in DSM-IV, and it is now more widely accepted that this phase is referred to as the “psychosis risk syndrome (PRS)”, a group of people referred to as This group is called “ultra-high risk for psychosis (UHR)”. Most people with schizophrenia have a prodromal phase that often lasts for a longer period of time before conversion. One study has followed 49 ultra-high risk individuals for one year and 20 of them converted to psychotic disorder, a conversion rate of 40.8%. A recent Meta-analysis showed a 1-year average conversion rate of 22% and a 2-year average conversion rate of 36% for psychosis risk syndromes. The lower conversion rate of psychosis risk syndrome in recent years compared to the previous years may be related to the increasing attention to prodromal symptoms. Therefore, early and timely intervention can help improve the prognosis of schizophrenia, and it is especially important to improve the identification and diagnosis of psychosis risk syndrome. II. Symptomatological early warning factors Possible risk factors associated with the onset of schizophrenia include family history, perinatal complications, premorbid social functioning, premorbid personality, and recent life events. It is now well established that there are often predictable factors in ultra-high-risk populations that can help improve disease recognition. In one study, eccentric beliefs and fantastical thinking were shown to be significant predictors of future conversion at baseline assessment. Another study found that ultra-high-risk individuals who converted to schizophrenia had more pronounced social withdrawal, introversion, and bizarre thinking. Therefore, it can be assumed that the ultra-high-risk population will mostly have characteristics of schizotypal personality disorder. At the same time, most will have subthreshold positive and negative symptoms, such as paranoia, perceptual abnormalities, and decreased social functioning. The following are commonly used to describe the prodromal features of schizophrenia: neurotic symptoms (anxiety, fidgeting, irritability, etc.), mood-related symptoms (depression, lack of pleasure, self-guilt, suicidal ideation, etc.), changes in volition (apathy, lack of interest, fatigue, etc.), changes in cognition (inattention, unresponsiveness, etc.), physical symptoms (somatic complaints, weight loss, poor diet, sleep disturbances, etc.), and weak positive psychotic symptoms (hallucinations, delusions, thought disorders, etc.), behavioral changes (social withdrawal, bizarre, impulsive, aggressive behavior, etc.), and other symptoms (obsessions, dissociation, sensitivities, etc.). However, these symptoms are less specific and cannot be diagnosed clinically in isolation from the prodromal phase, and only help to raise awareness of early warning of schizophrenia. The predominant diagnostic modality at present is with the help of identification tools.