We may well be able to control this kind of behaviour with
diet or drugs . Some illegal drugs and even alcohol promote aggresive
behaviour .
excerpt
Experiments using brain scanners while psychopaths perform
various tasks also have been accumulating.
They suggest that ''the psychopath finds it difficult to process,
handle, or use emotional material in the same way the rest of us do,''
said Robert D. Hare, professor emeritus of psychology at the
University of British Columbia and widely considered the world's
foremost authority on psychopaths.
Of course, that is the obvious problem, the very definition of a
psychopath: They lack normal feelings, like empathy and remorse. And
researchers have known for decades that psychopaths also tend to show
some unusual physical responses: They sweat less and generally exhibit
less distress when exposed to frightening or threatening stimuli, for
example.
Among all those researchers, those examining brain activity have
tended to find abnormal activity in the amygdala, a part of the brain
seen as the seat of basic emotions like fear, and the orbito-frontal
cortex, which is involved in helping people adjust their behavior in
response to reward or punishment.
Some studies also indicate problems in the connection between the
deep, emotional brain and the thinking part of the brain.
That anatomical finding combined with psychological tests show with
new precision that psychopaths have problems processing emotional
information, particularly things that make normal people afraid or
sad, Blair said.
And consider, he said, that ''the best way of teaching a child to feel
guilt about harming another individual is to focus the child's
attention on the victim's sadness. But that sort of socialization
technique doesn't work well with individuals with psychopathy,''
because they tend to be unable to feel empathy and to respond poorly
to cues associated with negative emotions.
In essence, Hare said, it appears that ''emotion for the psychopath is
like a second language,'' one he or she must struggle to speak and
never master deep down. Emotions for psychopaths are abstractions,
much as they are for Data or Mr. Spock on ''Star Trek,'' he said.
Even their murders tend to be dispassionate: A study of 125 Canadian
murderers found that among those with high psychopath scores on the
PCL-R, 93 percent of their killings were ''instrumental,'' practical,
rather than crimes committed in the heat of high emotion. That
cold-blooded quality makes them particularly dangerous, experts say.
As for treatment, past research has shown that most conventional
treatment, like group therapy, only makes psychopaths worse; it seems
to train them in manipulating people and faking emotions.
But Blair and some others believe that, within a few years, a drug may
be developed to treat psychopaths. People with depression and anxiety
problems can be helped by adjustments of their brain chemicals, he
said, and psychopaths effectively have the opposite problem in that
they feel too little.
''You would be able to help the systems that aren't working
particularly well by using a drug, so long as we understand what's not
working well,'' he said. So, perhaps ''we can give emotions to people
who lack them.''
bbc.co.uk
Chemical hint to aggression
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 ., 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 technolog
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