Two new medical studies say that ritalin for ADHD does not lead to drug abuse. One study, which followed almost 150 children with ADHD for 13 years, found that those who received stimulants appeared to have no increased risk of trying, using or abusing drugs as adults. Buried in the fine print, and ignored by media reports is the statement "Stimulant treatment in high school also did not influence drug use in adulthood except for greater use of cocaine."
As Slate explains, the effect of ritalin on the brain is almost identical to cocaine. Both are similarly controlled by the feds as Schedule II drugs. The main difference is that ritalin is taken in a slow-acting pill form, and doesn't have the immediate kick that cocaine snorters get.
So it makes sense to me that those who like ritalin, for whatever reasons, will also like cocaine.