Suicide

Postmortem brain tissue studies of suicide victims have found that the sertonergic systems (presynaptic and nontransporter nerve terminal binding sites) had reduced activity (Mann). Although there is optimism about new refinements and applications of neurobiological, brain imaging, and candidate gene markers to identify high risk individuals, there are currently no specific biological markers for suicidal behavior. With regard to older adults, it is conceivable that a ‘‘neurobiological vulnerability’’ to suicide might be modulated by age-related changes in neurobiological systems (Schneider). The consistency of increased suicide risk with age and male sex across nations also suggests a possible neurobiological process. Decreased brain concentrations of serotonin, dopamine, norepinephrine and their metabolites (HVA, 5-HIAA); increased brain MAO-B activity; increased hypothalamic-pituitary-adrenal (HPA) activity; and increased sympathetic nervous system activity are associated with both depression and normal aging (Schneider). Although several reviews have examined the evidence for neurobiologic abnormalities among older suicide victims relative to controls, there are too few studies that included sufficient ‘‘older’’ subjects (older than sixty years) to draw any conclusions (Conwell and Brent). This is particularly true of the subgroup of the older adults most at risk: those eighty-five and older.