speaking as a person who at one time had a very long and intense affair with LSD, i can say that the "flashbacks" are much exaggerated. they happen, but it isn't like falling into a random 8-hour trip all over again. also, i'm pretty sure neither of my children were born with any defects, physical or otherwise. as for long-term "effects," i think what they mean is that by taking LSD repeatedly and with the intent to expand your perception, you have a higher risk of not falling for their bullshit all the time, which is a problem, but not for the user.