Positron emission tomography studies of abnormal glucose metabolism in schizophrenia

Schizophrenia, a devastating disease characterized by a combination of various types of disturbed behaviors, thoughts, and feelings, may likewise be heterogeneous in etiology. Recent advances in neuroscience and psychopharmacology have suggested a wide array of competing mechanisms that may be involved in schizophrenia, including but not limited to deficits in one or more neurotransmitters and second messenger systems (e.g., dopamine, serotonin, gamma-aminobutyric acid, glutamate, and noradrenaline), neurodevelopmental defects in brain circuitry, and viral infection. Psychiatric genetic studies indicate that schizophrenia is a disorder with multifactorial inheritance. Since cerebral metabolic activity reflects regional brain work for all neurotransmitter systems, imaging metabolism directly with fluorodeoxyglucose and indirectly with blood flow and hemoglobin oxygen saturation can provide information about the functional neuroanatomy of a deficit in individual patients and allow patients to be grouped into more homogeneous subgroups for intensive study. This review summarizes metabolic imaging studies in schizophrenia over the past decade.