We have investigated neurotransmitter metabolites and glucose metabolism in incarcerated violent offenders, arsonists, and healthy volunteers. We have found that low cerebrospinal fluid (CSF), 5-hydroxyindoleacetic acid (5-HIAA) concentrations, and hypoglycemia during oral glucose tolerance tests are associated with each other and impulsive violent acts and fire setting. In a follow-up study, we found that a low blood glucose nadir and low CSF 5-HIAA concentration were powerful predictors of recidivism among impulsive violent offenders and fire setters. We have documented a profound disturbance of day-night activity rhythms in alcoholic violent offenders with intermittent explosive disorder. The personality abnormalities associated with low CSF 5-HIAA in alcoholic violent offenders were found to be chronic irritability and psychasthenia. Sample collection for the molecular genetic family study on alcoholic violent offenders has been completed. The clinical data have been blind rated for psychiatric diagnoses and all biochemical and physiological data have been entered in the computers and double checked for errors. Molecular genetic analyses in the Laboratory of Neurochemistry are underway.