Rats show cure for addiction may lie in brain's chemistry  ·
Treating defect may prevent dependency · Researchers find
'brake' that regulates impulses  Some people are predisposed to
drug addiction because of the way their brains operate, say
researchers who studied rats dependent on cocaine. Their
findings pinpoint a "hidden vulnerability" that make the rats
more impulsive and more likely to become dependent on the drug.
"We have known for a long time that some behaviours are
associated with drug addiction - such as impulsivity and risk
taking in general," said Gerome Breen, an addiction researcher
at the Institute of Psychiatry, King's College London. "What
this study does is identify a biological basis for the behaviour
and the mechanism by which it leads to addiction."  Dr Breen,
who was not involved in the research, said that although the
brain defect makes rats more vulnerable to drug addiction, the
finding could not be used to identify people who are "born
addicts". He said: "The biggest determinant i