Drug addiction genetic makeup

Chinese experts, this drug addiction is somehow related to a person's genetic makeup.
According to Chinese scientists, they have identified around 400 genes that seem to make some people more addicted to drugs compared to others.
Furthermore, the results show that the environment factor consisting of peer pressure, neighborhood and the likes only comprise 40% of a person's vulnerability to drugs, while the remaining 60% is attributed to the said genes.
The scientists used four addictive substances in the study namely cocaine, opiate, alcohol and nicotine and mapped out five molecular pathways that trigger addiction. The genes in question turned up more frequently in the determined pathways.
"These common pathways may underlie shared rewarding and response mechanisms and may be targets for effective treatments for a wide range of addictive disorders," commented the scientists.