The current study will improve knowledge on the effectiveness and safety of the use of antipsychotics at the prodromal phase and on factors influencing the outcome, and will eventually facilitate optimisation of individualised interventions for psychosis prevention and treatment.

Help-seeking first-visit participants will be consecutively recruited. Every participant meeting the inclusion criteria will be fully informed of the study and asked to sign the written informed consent before enrolment.

Two senior nurses that will conduct the initial screenings were employed to collect all diagnostic and medication information from medical records on every follow-up visit. The four psychiatrists are qualified and well-trained and will conduct the SIPS/SOPS interview at baseline and follow-up.

The investigators will systematically record medication information. A model will be established to correlate antipsychotics with clinical and functional outcomes and demonstrate whether antipsychotics are useful and safe for preventing CHR individuals from converting to psychosis.

Based on experience from the sampling process in the SHARP-1 project, the investigators will recruit 600 participants at CHR. Considering a dropout rate of 20%, 510 cases of CHR will be followed up. According to the sample size calculation formula in superiority clinical trials of new drugs, the sample size of 600 cases is adequate for the demonstration of the effectiveness and safety of antipsychotics in CHR subjects.

Inclusion Criteria:

• be aged 14 to 45-year-old
• have had at least 6-years of primary education
• be drug-naïve
• be understanding the survey, be willing to enrol in the study and sign the informed consent
• Through the Structured Interview for Prodromal Syndromes/Scale of Prodromal Symptoms (SIPS/SOPS), the participants should meet the Criteria of Prodromal Syndrome. Participants should fulfil at least one of the prodromal syndrome criteria: (1) brief intermittent psychotic syndrome, (2) attenuated positive symptom syndrome, or (3) genetic risk and deterioration syndrome

Exclusion Criteria:

• Through the Mini-International Neuropsychiatric Interview (MINI), Axis I mental disorders such as schizophrenia, affective disorders, and anxiety spectrum disorders will be excluded
• Acute or chronic renal failure; liver cirrhosis or active liver diseases
• Abnormal laboratory tests results judged by the researchers to be clinically significant and considered to affect the efficacy of the test drugs or the safety of the subjects
• Severe or unstable physical diseases, including: neurological disorders (delirium, dementia, stroke, epilepsy, migraine, etc.), congestive heart failure, angina pectoris, myocardial infarction, arrhythmia, hypertension (including untreated or uncontrolled hypertension), malignant tumours, immune compromise, and blood glucose above 12 mmol/L
• Alcohol abuse within 30 days, or alcohol or drug dependence within 6 months before the trial
• Pregnant or lactating women, or women in childbearing age who are positive in urine human chorionic gonadotropin test, or men and women who do not take effective contraceptive measures or plan for pregnancy within 3 months after the initiation of the trial
• Stroke within the last month
• Participating in any clinical trial within 30 days before the baseline
• Other situations judged by the investigators not to be suitable for the clinical trial

Help-seeking first-visit participants will be consecutively recruited from the Shanghai Psychotherapy and Psychological Counselling Centre at the Shanghai Mental Health Centre. They will be screened for eligibility by their clinicians.