i hardly think that john lennon himself would agree that lsd never caused him "the slightest problem".
Well he said in the playboy interview in 1980 that he took millions of trips in the sixties and never had a flashback in his life and "I'm not promoting LSD so don't all you committees start writing to me but all the things the government says it does to you are bullshit".
he experienced such horrific trips on LSD he had to stop using it
Yeah, he stopped for about a fortnight. After taking it almost daily for 18 months. Then he went back to it and tripped with Yoko and Derek Taylor and had one of the most profound, positive experience of his life. In 1974 he wrote to Derek saying "Found some nice windowpane, my mind is clear" so he kept using it.
Incidentally, having a bad trip is not the same thing as having mental illness. You can have a bad trip and not be mentally ill.
Part of Rolling Stone interview with John Lennon
How did you first get involved in LSD?
A dentist in London laid it on George, me and the wives, without telling us, at a dinner party at his house. He was a friend of George's and our dentist at the time, and he just put it in our coffee or something.
When you came down, what did you think?
I was pretty stoned for a month or two. The second time we had it was in L.A. We were on tour in one of those houses, Doris Day's house or wherever it was we used to stay, and the three of us took it, Ringo, George and I. Maybe Neil [Aspinall] and a couple of the Byrds - what's his name, the one in the Stills and Nash thing? - Crosby and the other guy who used to do the lead. McGuinn. I think they came, I'm not sure, on a few trips. Peter Fonda came, and that was another thing. He kept saying [in a whisper], ``I know what it's like to be dead.'' It was a sad song, an acidy song, I suppose. ``When I was a little boy'' . . . you see, a lot of early childhood was coming out, anyway. So LSD started for you in 1964.
How long did it go on?
It went on for years, I must have had a thousand trips. Literally a thousand, or a couple of hundred? A thousand - I used to just eat it all the time.
The other Beatles didn't get into LSD as much as you did?
George did. In L.A. the second time we took it, Paul felt very out of it because we are all a bit slightly cruel, sort of ``we're taking it, and you're not.'' But we kept seeing him, you know. We couldn't eat our food; I just couldn't manage it, just picking it up with our hands. There were all these people serving us in the house, and we were knocking food on the floor and all of that. It was a long time before Paul took it. I think George was pretty heavy on it; we are probably the most cracked. Paul is a bit more stable than George and I.
And straight?
I don't know about straight. Stable. I think LSD profoundly shocked him and Ringo. I think maybe they regret it.
Did you have many bad trips?
I had many. Jesus Christ, I stopped taking it because of that. I just couldn't stand it.
You got too afraid to take it?
It got like that, but then I stopped it for I don't know how long, and then I started taking it again just before I met Yoko. I got the message that I should destroy my ego, and I did, you know. I was slowly putting myself together round about Maharishi time. Bit by bit over a two-year period, I had destroyed me ego. I didn't believe I could do anything. I just was nothing. I was shit. Then Derek [Taylor, Apple press officer] tripped me out at his house after he got back from L.A. He sort of said, ``You're all right,'' and pointed out which songs I had written: ``You wrote this,'' and ``You said this,'' and ``You are intelligent, don't be frightened.'' The next week I went to Derek's with Yoko, and we tripped again, and she made me realize that I was me and that it's all right. That was it; I started fighting again, being a loudmouth again and saying, ``I can do this. Fuck it. This is what I want,'' you know. ``I want it, and don't put me down.'' I did this, so that's where I am now. At some point, right between `Help!' and `Hard Day's Night,' you got into drugs and got into doing drug songs. A Hard Day's Night, I was on pills. That's drugs, that's bigger drugs than pot. I started on pills when I was fifteen, no, since I was seventeen, since I became a musician. The only way to survive in Hamburg to play eight hours a night, was to take pills. The waiters gave you them - the pills and drink. I was a fucking dropped-down drunk in art school. Help! was where we turned on to pot, and we dropped drink, simple as that. I've always needed a drug to survive. The others, too, but I always had more, more pills, more of everything because I'm more crazy probably.
How do you think LSD affected your conception of the music? In general?
It was only another mirror. It wasn't a miracle. It was more of a visual thing and a therapy, looking at yourself a bit. It did all that. You know, I don't quite remember. But it didn't write the music. I write the music in the circumstances in which I'm in, whether it's on acid or in the water.
Or somthing ................................................ like that 
