The Creation records founder admits he started taking ecstasy in the late 80s, and that by the time he signed what would go on to become his most successful act, his drug use had become out of control.
He told the Daily Record newspaper: "Did I have a breakdown or did I have a breakthrough? I don't know, maybe a bit of both. Maybe I had to have a breakdown to have a breakthrough.
"The drugs had moved on and were a lot harder by then. I recall signing Oasis but I barely remember anything else. Ninety three was my lost year, I was already bad."
Alan went to rehab, and when he returned, and first listened to the song 'Wonderwall' - one of Oasis' defining moments - he said he knew it would be a huge success and things would be good for the record label.
He added: "I came out of rehab sober, put on 'Wonderwall' and thought, 'We're going to sell 10 million'. I was wrong - we sold 21 million.
"Money was never a problem after that."
Oasis' album '(What's The Story) Morning Glory', featuring 'Wonderwall' has sold over 21 million copies worldwide, and is also the third best selling album in UK chart history.