Neurobiological aspect of suicide; a review of low cerebrospinal 5 hydroxyindoleacetic acid concentration and prediction of suicidality
Finding an indicator that can point to a high risk group for suicide has long been a desirable aid for the prevention of completed suicides. The studies reviewed in this essay presume that a biological aspect can point out the high risk individual. The focus of the studies lies on the serotonin 5-hydroxytryptamine (5-HT) monoamine neurotransmitter and cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) which is the principal metabolite of 5-HT in depression. The studies on 5-HT metabolites have led to the belief that these may play a key role in the neurochemistry of suicidal behaviour. It is suggested that the core behavioural effect of low CSF 5-HIAA concentration might result in an increase in impulsive and violent behaviour to self and others. The predictability is based on the fact that patients with low CSF 5-HIAA are more prone to reattempt and complete suicide by violent means. A number of well-designed studies concerning suicidal individuals and control subjects have however not shown any difference in concentration of CSF 5-HIAA in suicide attempters compared to non-suicide attempters which could be explained by methodological flaws. Low CSF 5-HIAA does seem to characterize the high risk individual, but it is not yet determined what role it plays in actual suicidality.