Understanding the neurobiology of suicidal behavior

Our current knowledge about the neurobiology of suicide is still limited. T echnical limitations and the complexity of the CNS are major obstacles. How ever, there is evidence for a hereditary disposition to suicide, which appe ars to be independent of diagnosis. Clinical, postmortem, genetic, and anim al studies suggest that serotonin has a central role. The main regions of i nterest in the CNS have been the dorsal and median raphe nuclei in the midb rain that host the main serotonergic cell bodies and the prefrontal cortex, particularly the ventral PFC, innervated by the serotonergic system. In vi vo and postmortem studies indicate serotonergic hypofunction in suicide and serious suicide attempts. This deficiency in turn can lead to a predisposi tion to impulsive and aggressive behavior, probably due to a breakdown in t he inhibitory function of the ventral prefrontal cortex as a result of less serotonin input. In the context of this predisposition and the development of mental illness or other life stressors, the individual is at risk of ac ting on suicidal thoughts. Such deficient serotonin input into the PFC may arise as a result of genetic, parenting, bead injury, and other effects. Id entifying psychiatric, social, and environmental predictors of suicide are studied to improve prediction and prevention of suicide. A better understan ding of the neurobiology of suicide can help detect at risk populations and help develop better treatment interventions. (C) 2001 Wiley-Liss, Inc.