The data supporting the idea that there are alterations in serotonin & norephinephrine in the ventral prefrontal cortex & brainstem of suicide victims are reviewed. Serotonin responses are defective at least in the hypothalamus. Suicide victims appear to have fewer noradrenergic LC neurons. A failure of behaviour restraint mechanisms involving the prefrontal cortex as a consequence of alterations in brainstem monoaminergic nuclei may result in a predisposition to suicidal behaviour. (93 refs.)