There was recent news on the detrimental effects of general anesthesia has on the very young and old. Apparently it can be neurotoxic but healthy adults don't seem to have long lasting problems.
A family friend of mine went under general anesthesia and woke up senile. He was in his late-70s, early-80s at the time. Lives in a nursing home now. Once in a while can have some moments of somewhat clarity but they only last for a minute or two.
__z|10 years ago