Drugs are my specialty as both a user and a student of their chemical use effects and causing of dependency in a user. I do not condone or suggest the use of drugs, They are however your choice and you must except the consequences. The following is for informational purposes and in no way to encourage drug use...
Drugs ARE bad...
You want to know what kind of drug may cause or accelerate the forming on schizophrenia or other disorders...
Quote: " Cocaine, for example."
Yes cocaine causes seratonen receptors in the brain to become fried causing depression which is a very likely going to accelerate and cause brain deterioration in relativity to schizophrenia. Other drugs that cause seratonin receptors to become fried are the Crack form of cocaine and Ecstacy.
Quote: "Marijuana can lead to it too iirc."
Doubtful seeing as the active chemical in Marijuana, Tetrahydracannabinol(THC) mostly attacks the memory.
Lysergic Acid Diethylamide aka LSD or Acid causes severe mental problems(i knew a guy on a permanent trip who thought he was a glass of orange juice) and most definitely could cause schizophrenia. As for the legal amount before your legally insane was 3 hits last i checked.
Psylocibin or mushrooms could cause mental deterioration but i don't know that much about how.
Methamphetamines or Crystal Meth cause severe problems after continued use...not sure of exactly what...
As for any other drug...there are a quite a few possibility...
If you want to ask me about it you can find me in the channel #altering on the darkbasic IRC server most of the time...
Who am i...i don't know anymore...its been a long time since ive walked here...