According to Healthline, vitamins can be an effective way to help reduce symptoms of schizophrenia. In particular, vitamins B9, B12 and B6 are the most effective at reducing symptoms. Fish oil supplements are another recommendation as a potential alternative medicine for schizophrenia. However, while medicine can help to reduce symptoms, it’s important to remember that schizophrenia is a mental illness for which there is no definitive cure.