The thought came to me when I was hearing one of my friends attempting to sound deep as he had some form of "grand revelation" over the week (gotta love stoner philosophy

) and claimed he was a completely different person. Some of it was sort of true, as he used to be more on the uptight side and always worried about everything around him.
I saw this trait in alot of other people, all with varying results, and from many age groups with some beyond the age range you posted. Originally this was a more general quandry, and not meant for any specific nationality or age group, but now that you mention it, many were in their 20s...