Many people have received sub-optimal treatment for their schizophrenia or affective disorder. Despite a large monetary investment, over a prolonged period, pharmaceutical companies have failed to deliver novel therapies to the market place. Based on anecdotal testimony and with strong literary support, a pilot study was undertaken. For the randomized controlled trial, 80 participants self-administered either mangosteen pericarp or placebo capsules over an 180 day period. No biomarker has been widely recognized for schizophrenia, so widely accepted measures of outcome were accessed by structured interviews. This book reported if supplementary capsules of mangosteen extract (pericarp), modified symptoms for the treatment of schizophrenia and affective disorders.