Counter-counter anecdote:
I was just listening to an interview[1] with Dennis McKenna[2] (brother of Terence McKenna[3]) in which he said:
"If I'm going to take it [a psychedelic substance] I'm going to pay attention to it. It's sort of like you have an opportunity to sit with someone who's very wise and they have stuff to tell you and so they deserve that respect. That's what's changed. I give it my respect.
"And sometimes people say, well, you've been doing this 50 years haven't you got the lesson yet? .. there's one perspective that says 'once you get the message hang up the phone'.
"Well, maybe I'm a slow learner but I'm still learning from these things. They're not like an answering machine. It's not like there's only one message.
"It's like if you had a mentor, a teacher, someone who you respect you're not going to reach a point where you say, 'well, basically I've learned everything you have to tell me so thank you very much and I'll be on my way.' Chances are they still know more and they always will know more than you will know.
"Every time I take ayahuasca or mushrooms I learn something new or I am reminded of what I've forgotten, what's easy to forget in the day-to-day hustle of life. I just feel it's still valuable. In some ways it's a touchstone. It's a way of getting back to that place, that sacred space, sacred time environment where you can remind yourself of the eternal truths."
Second counter-anecdote:
Ram Dass[4], in his 80's after suffering a stroke, when asked in an interview that I can't find at the moment about what LSD has done for him replied "I'm happy. I've had a stroke and I'm happy. That's LSD."
[1] - https://www.youtube.com/watch?v=KGYm5OdvwNs
[2] - https://en.wikipedia.org/wiki/Dennis_McKenna
[3] - https://en.wikipedia.org/wiki/Terrence_McKenna
[4] - https://en.wikipedia.org/wiki/Ram_dass