I dont think it the smoking of weed that leads to stronger substance abuse but, the motive behind smoking it. If you are taking it to get escape reality and problems, then yes over time i think that one may become fed up with the same old buzz and then may go on to the stonger stuff. If weed is taken soley as a recreational drug like alcohol then the answer is no. I personally know people that have been smoking weed for years and they dont appear to be suffering from mental health problems