many people are under the impression that drugs or alcohol are the causes, they ignore the fact that millions, no billions of other people suffer no problems, you could just as easily say easting bread is the cause. drugs and alcohol are often symptoms of mental health problems, not the cause. its a common misconception, i guess people who havent had a sincere long term addiction wouldnt understand.According to a friend of ours who is a psychiatric nurse, over a third of her patients in the secure unit where she works are drug induced psychotics and another third are alcohol induced psychotics.