Not a tight one. High-performing students sometimes feel under so much pressure that they turn to drugs to "relax"; low-performing students may use them because "no one cares." casual use of drugs doesn't necessary cause problems, but it is quite rare for students who begin using drugs heavily to be able to maintain a high academic performance.
No. Like anything else, it depends on multiple factors. "abusing drugs, " in this context, implies a "drug problem." drug use, in and of itself, is not a problem. Like "hearing voices, " in and of itself, is not a problem. Psychiatric problems are a problem when they...Well...Become a problem. You can "hear voices" all day long. But, if they are nice and helpful, is that so bad?