Chemical hint to aggression

Brain fluid holds clues to psychopathic behaviour

Brain fluid holds clues to psychopathic behaviour.The levels of two chemicals in the spinal fluid may give doctors extra clues about the presence of psychopathic personality traits. The findings of a Swedish research team may also bring scientists closer to understanding the root cause of these problems. The chemicals involved, known in short as HVA and 5-HIAA, are by-products of the breakdown of two key brain chemicals which send messages around the organ. The levels of these brain chemicals, dopamine and serotonin, have already been linked to mood and personality traits. In the latest study, a group of 28 men, all of whom had committed violent crimes, including murder, assault, and rape, were persuaded to allow a sample of their cerebrospinal fluid – the liquid which bathes the brain and spinal cord – to be taken by doctors. Chemical levels After a standard personality rating system had been used to assess the men, this was compared against what was found in the fluid. The Swedish team found that higher levels of HVA – the chemical linked to dopamine, combined with lower levels of 5-HIAA – linked with serotonin – was found in men who displayed psychopathic traits. It was the ratio between the two chemicals which seemed to predict the psychopathy “score” generated by the tests. It was also linked strongly to a history of disruptive behaviour in childhood. The findings, published in the Journal of Neurology, Neurosurgery and Psychiatry, offer more evidence that serotonin and dopamine levels may be important in psychopathic behaviour. It does not yet tell doctors whether the condition has a cause that medicine may one day be able to correct or treat. Dr Mairead Dolan is researching the brain chemistry of antisocial behaviour at the University of Manchester. She told BBC News Online: “Although cerebrospinal fluid metabolites such as these are not the most direct mechanism of controlling neurotransmitter function, the work provides further evidence for the need to understand the neurobiology of antisocial behaviour using the most advanced technologies.” (Source: BBC, Friday, 20 June, 2003, 23:29 GMT 00:29 UK)