Dependence on marijuana may have a genetic basis, according to research at Yale University. The study of more than 14,000 persons also found that a risk for dependence on marijuana may mean a higher chance of inheriting major depression, according to a release. “We were surprised to find a genetic risk overlap between cannabis dependence and major depression,” said Dr. Joel Ge­lernter, a psychiatrist and professor of genetics and neuroscience, who was senior author of the study. The research showed that both dependence on marijuana and depression could be inherited. People who demonstrated dependence on cannabis were compared with others who had little or no sign of such dependence and it was found that several variations in genes could predict who would become dependent. This relationship is similar to the genetic risk for alcohol addiction, the release said. [Read more at the New Haven Register]