Could you actually have an LSD flashback decades after taking the drug?

Ever hear someone tell a tale about an elderly man who used LSD in his youth going on a fish trip, only to randomly have an LSD-linked flashback and die via drowning? Scary, eh? I remember this urban legend particularly well, thanks to an unusually creepy elementary school assembly about drug awareness. » 10/19/12 4:20pm 10/19/12 4:20pm