I remeber seeing a study.....
Researchers said they were particularly interested in the survey results of marijuana use in the Netherlands, known for its relatively permissive drug laws.
While marijuana use was relatively widespread there -- 28 percent of 10th graders had tried it, compared with the European average of 17 percent -- four other European countries, Ireland, France, the Czech Republic, and Britain, had higher rates, as did the United States
I think the main reason pot leads others into harder drugs is becuase of the people you spend your time with. If you spend your time with and begin socilizing with drug users and dealers, then eventually you will be lead towards harder drugs.