Post-mortem studies in psychiatric disorders antemies to be a useful method for testing hypotheses. New findings include the following: (1) Decreased tritiated clonidine binding in the locus coeruleus of schizophrenic patients; (2) Increased methionine-enkephalin in the substantia nigra of schizophrenic patients; (3) Increased serotonin (5-HT) and 5-hydroxy-indoleacetic acid (5-HIAA) in basal ganglia and occipital cortex, respectively, in schizophrenic patients; and (4) Decreases in 5-HT and 5-HIAA in hypothalamus and nucleus accumbens, respectively in suicides.