The purpose of this study is to determine whether Taurine 4g is effective with antipsychotic medication in the treatment of First Episode Psychosis.Taurine may have an effect on cognition and symptoms. We are examining changes in symptoms and cognition over a 3 month period.

The core rationale of this study will be to prospectively investigate whether Taurine will improve and /or protect cognitive functioning and improve symptomatology in a cohort of 128 first episode psychosis patients.This is a randomized, double blind placebo controlled add on standard therapy trial of Taurine 4g , in young patients between 18-25 presenting to ORYGEN Youth Health a sub program of Melbourne Health and RAPPS, a subprogram of Southern Health with a first psychotic episode . Taurine will be compared with placebo added to standard treatment for a period of 12 weeks in a double blind fashion.Primary outcome measures will be psychopathology and cognition (MATRICS.

Secondary outcome measures will be tolerability and safety measures (drop-out rates, general side effect scale (UKU).

Patients who give informed consent will be randomised to receive treatment with Taurine 4g daily or placebo for 12 weeks.

Patients will be randomised by a dynamic randomisation method called minimization which allocates patients to treatment group by checking the allocation of similar patients already randomised, and allocating the next treatment group "live" to best balance the treatment groups across all stratification variables. The minimization will be carried out by the NHMRC clinical trials centre in Sydney , and the patient will be randomized to either placebo or vitamin.

Each patient will collect their tablets from the clinical trials pharmacy. The Clinical Trials Pharmacy will dispense either vitamin or placebo. All study personnel and participants will be blinded to treatment assignment for the duration of the study.

Inclusion Criteria:

• Male and females
• Between 18 and 25 years of age
• First Episode Psychosis
• Attending ORYGEN Youth Health, a geographical based catchment area service for young people aged between 15 and 25.

Exclusion Criteria:

• Organic disorders presenting with a psychotic syndrome (e.g. brain tumour, temporal lobe epilepsy, HIV encephalopathy)
• Mental retardation (unable and/or unlikely to give appropriate information of symptomatology or side-effects (IQ approximately lower than 80)
• History of clinically significant physical illness (e.g. terminal cancer, renal dialysis)
• History of brain surgery
• History of brain infarction
• Pregnant or lactating women or women of childbearing potential not using an acceptable method of contraception.