An 'addiction gene' that runs in white women, discovered by scientists at Yale University, puts at high risk of drink or drug abuse.
The finding paves way for a DNA test to screen for those people who are most at risk of becoming drug addicts or alcoholics.
In a study of 3,627 volunteers, the researchers found that women of European origin with a mutated version of a gene, known as PKNOX2, were almost twice as likely to become substance abusers than those without the variant.
However, no such link was found among black people or men.
The researchers defined addiction as being dependent on at least six substances including nicotine, alcohol, marijuana, cocaine, opiates or other drugs.
"We have found a genome-wide significant association of a composite substance dependence with a mutation in the PKNOX2 gene in white women," the Scotsman quoted epidemiologist Dr Xiang Chen, of Yale University, as saying.
The gene was linked with alcohol addiction in mice in research published several years ago, but has not been reported before as being associated with substances dependence in humans.
"Our findings make an important contribution in reporting PKNOX2 as a candidate gene for substance dependence, particularly for white women in the sample," Chen said.
The study has been published in the journal Proceedings of the National Academy of Sciences.