What are effects of 'tripping' on lsd 40 years later? has anyone looked?

Flashbacks: Flashbacks have been described after use of lsd years later I am not aware of any studies looking at the effect of lsd that long after having used it.

LSD tripping: "hallucinogen persisting perception disorder" has been reported for decades, and is rare. About 20 studies have been done, but we still know little about this condition which can be very limiting to people. There are some case reports of attempts to use antipsychotics & other medications to treat it. It's hard to find enough people to study. http://www.ncbi.nlm.nih.gov/pubmed/12609692.

Better mental health: I don't believe studies have followed people for as long as 40 years but studies have generally found that the vast majority of those who used lsd many years ago ascribe a variety of long-term mental health benefits to their experiences- greater self-awareness, happiness, inner peace etc. Of course, some have had negative experiences as well. See http://www.Ukcia.Org/research/cunion/cu52.Htm.