Neurotransmitters in Treatment Resistant Schizophrenia Patients With add-on Sodium Benzoate

Inclusion Criteria: 1. Fulfil the DSM5 criteria for schizophrenia or schizoaffective disorder 2. Research criteria for treatment resistance: little or no symptomatic response to multiple (at least two) antipsychotic treatment of an adequate duration (at least 6 weeks) and adequate doses (equivalent to at least 600 milliequivalent (meq)/day of chlorpromazine) 3. 6 month period without remission (i.e. ≥4 item-score for the positive symptoms on PANSS scale , especially delusional thoughts, conceptual disorganisation, excitements, grandiosity, hallucinatory behaviour, excitement, persecution, and hostility) 4. The persistence of illness was defined as a score of ≥4 (moderately ill) on the severity of illness subscale of the Clinical Global Impression scale (CGI-S), and a lack of stable period of good social occupational function. Exclusion Criteria: 1. Current or previous diagnosis of concurrent DSM-5 disorder due to active medical problems, known neurological disease, or a contraindication to MRI scanning 2. Current diagnosis of substance-related disorder 3. Any acute or chronic medical condition 4. History of head trauma or neurological diseases.