The goal of the study is to investigate whether adding different doses of sulforaphane will benefit the clinical symptoms and cognitive function in individuals who have schizophrenia.

This study will compare the sulforaphane with placebo. There is a thirty percent change (less than half) of receiving the placebo. The purpose of including placebo is to judge if the outcome is related to the study medication rather than other reasons.

This study will be carried out in six mental health institutes in China and total of 180 patients with first-episode or early onset schizophrenia will be enrolled into the study. The mental health institute at the Second Xiangya Hospital, Central South University.

Individuals who participate in the study will be followed for 24 weeks. The changes in clinical symptoms and neurocognitive function will be assessed from baseline (week-2) to week-6 (acute phase), and week-12 to week-24 (maintenance phase).

Inclusion Criteria:

1. Meet The Diagnostic and Statistical Manual (DSM-V) diagnostic criteria for schizophrenia
2. First onset or duration of illness less than 3 years with current symptoms exacerbation
3. Hospitalized in an acute episode (first hospitalization), or subsequent hospitalization or acute relapse)
4. Male and female with aged 18 to 50 years
5. PANSS total >=75 at 2 weeks. .
6. Signed the study consent for participation

Exclusion Criteria:

1. having history of substance dependence or abuse or whose symptoms are caused by the other diagnosable mental disorders;
2. having history of traumatic brain injury, seizures or other known neurological or organic diseases of the central nervous system;
3. taking antidepressants, stimulants, mood stabilizer or accepts electricity shock treatment;
4. having current suicidal or homicidal thoughts or any safety concern by research staff that cannot be manage in an inpatient setting;
5. the routine blood tests showing abnormal renal, liver function or other metabolic results .
6. pregnant or lactating women

Participants and researchers are blind to treatment allocation (double-blind). An independent researcher developed the computer-generated randomization plan.