It transforms the lives of many 'hyper' children, but as pupils peddle it at school, a new drug nightmare is unfolding. Simon, 14, is a hit with the girls. At most afternoon breaks, he can be found surrounded by a posse near the netball court at their comprehensive school in northern England. They want his drugs, but not to get high. They want Ritalin to suppress their appetite and help preserve their wafer-thin frames. Simon is popular with the boys, too. However, they want only to get high, crushing the tablets and snorting a substance chemically similar to cocaine for...