So, acting as an alarm clock to a user's hibernating psychotic tendencies is the closest LSD comes to "causing insanity." However, even drug-related psychosis isn't exactly "insanity" as it's popularly defined. For one thing, it's temporary, only occurring during use and withdrawal. The symptoms of such psychosis are delusions and hallucinations -- and do you know which other, totally legal drug can cause the exact same symptoms? We bet you can't guess. Go on, guess.
That's right: Alcohol actually causes psychotic behavior much more widely than LSD. A study found that in 2007 more patients (over 160,000 people) were diagnosed with alcohol-related psychosis than with alcohol-related liver damage (cirrhosis). As a matter of fact, you've sort of known about this since you were a kid, even though you may not realize it: Remember the scene in Dumbo where the titular elephant overdoes it on the bubbly, kicking off the "Pink Elephants on Parade" musical number? Yeah, "seeing pink elephants" is a euphemism for alcohol-related psychosis. Oh, that Walt Disney ... always using his kiddie pictures to poke fun at serious societal issues.
"OK, that's a good start. Now, can we make the clouds rain blood that the castle is vomiting?"