Because the "LSD psychosis" is not distinguishable from non-drug-induced psychosis, we have reasonable evidence to conclude that LSD was not the sole cause of psychosis. Instead, it would seem that the drug brought on the problems in vulnerable individuals. Interestingly, the rate of parental alcoholism was found to be much higher in LSD patients than in other patients or in the general population by one study (Vardy and Kay, Arch-Gen-Psych, 1983 40(8): 877-83).

erowid faq