wow. I never heard of LBD until I read this. And forgive me, but I have to wonder if this was present in his brain to a lesser degree for years, or if it just presented itself in the last couple of years preceding his death.
It's no secret that Robin Williams wasn't afraid to try new things. LSD, Alcohol, probably numerous other types of drugs as well. I certainly couldn't say those things contributed - but I can certainly say they likely didn't help, either.
One thing is for sure, he had amazing talent for entertaining. Acting, comedy, music - not a lot of people could measure up to him.