Tomography) scan of an axial section of the brain of a person suffering untreated schizophrenia. The use of the radioactive tracer methionine" (an amino acid) injected into the body, shows protein synthesis in the brain. The tracer appears red, with frontal lobes of the brain (at top) appearing deficient; more red areas of protein synthesis would be expected in this area in a normal brain. In schizophrenia, changes in mood are typical. The neurotransmitter "serotonin" is one chemical made in the frontal lobes of the brain which controls moods. Low protein synthesis & abnormal serotonin levels may be associated with schizophrenia."