The purpose of this study is to determine whether individuals with schizophrenia who will take a high dose of the B-vitamins folate, B12 and pyridoxine, may experience improvement in their symptoms.

Individuals with schizophrenia often experience disturbing residual symptoms, even with the best available current treatments. Homocysteine, normally found in the body, can interfere with NMDA-glutamate receptor function, and this might be responsible for some of the symptoms of schizophrenia. This double-blind protocol will have study participants who suffer from schizophrenia take either a high-dose combination of folate, B12 and pyridoxine (a combination that can lower homocysteine in the body) or placebo for three months. Clinical measures (e.g., PANSS, CGI) will be taken to determine whether those taking the vitamin combination experience clinical benefit.

Inclusion Criteria:

• Clinical diagnosis of Schizophrenia or Schizoaffective Disorder
• Ages 18-65, male or female
• Treatment regimen includes a new-generation antipsychotic (clozapine, olanzapine,risperidone, quetiapine, ziprasidone or aripiprazole)
• Stable medication for 4 weeks prior to screening visit

Exclusion Criteria:

• Diagnosis of active substance use disorder within the last month
• Already taking vitamin supplements totaling > 400 mcg folic acid per day, or regular B12 injections
• Pregnant or breastfeeding
• Seizure disorder
• Non-English speaking
• Without capacity to give informed consent