The assessment of beta-endorphin levels in several symmetrical brain regions of seven suicides and seven sudden death controls reveals a decreased concentration in the left temporal cortex, the left frontal cortex, and the left caudate nucleus of suicides compared to controls. Moreover, the comparisons of beta-endorphin concentrations in the symmetrical brain regions reveals an asymmetrical concentration in suicides (left less than right) in frontal cortex and caudate nucleus. These data confirm previous reports of abnormalities of neurochemical pathways in the brains of suicides and suggest that suicidal behavior might be related to the lateralized mechanisms of mood control.