Merson warned that there were troubled times ahead if Villa failed to appreciate the extent of his endeavours to overcome addiction problems. The England player is furious at the "negative vibes" that greeted him at Villa after his weekend trip to New York. He admitted to being "depressed and down" in recent weeks and that Gregory needed to recognise the importance of such breaks in his rehabilitation programme, as had Robson.
"If I felt guilty about what I had done, then I would put my hand up - but I know just how close I was to the edge in the past," Merson said. "Villa might have paid a lot of money for my services but you can't put a price on life and I know what I went through with my addictions. This wasn't me making a flash sort of trip and I am not one of those people who thinks they are bigger than the club.
"What I did was right for me given my circumstances. I had the weekend off and needed to get away. Villa knew I was feeling down so I can't see what all the fuss was about.
"Bryan Robson was good as gold with such things. If I needed a few days off, to get away, then he would understand. There was one stage last season at Middlesbrough when I was feeling down that he was going to send me to Tenerife for a week. I had the same sympathy from the managers when I was at Arsenal.
"If Villa want to get the best out of Paul Merson then the same leeway needs to be shown. If the boss [Gregory] here, doesn't understand then there are going to be problems."
Merson admitted: "If I am doing well and putting everything into the game then everything is all right. But when I am not doing the business or can't play a proper part, which has been the case with having the back problem, then that's when you get all sorts of things in your head. That's when I start to go a little bit. I didn't say anything before I went away but I was injured, I wasn't in the team. I wasn't involved and it wouldn't have been very nice for me if I had gone back to Middlesbrough to watch Saturday's game.
"I asked the physio [Jim Walker] for the Monday off. He knew how I felt. He knew I was down. I was back on Tuesday, played in the reserves on Wednesday and felt OK. But all I've got since I've come back is negative stuff which is frightening - and it has really opened my eyes.
"Personally, it would have been nice for me if Villa had come out and said, `Paul has gone away for a few days and when he comes back he will be buzzing,' but that hasn't happened. The manager hasn't spoken to me since I got back."
Merson made his comeback in Wednesday's reserve game but is pessimistic about being picked for Monday's home Premiership meeting with Everton.
"I was ahead of schedule by playing on Wednesday and think I can play for an hour on Monday and help to create chances," he said. "But I'm not optimistic of being picked against Everton on Monday - and if that is the case then Wednesday was a waste of time."
Merson is unlikely to return to his addictions after the spat with Gregory, according to a leading psychologist. Cary Cooper, professor of psychology at the University of Manchester Institute of Science and Technology, believes the situation has arisen because of a "breakdown in communication" between the two men.
"Anyone who has an addiction is somebody who is not coping very well," Prof Cooper said. "When the pressure pushes them, they follow the way they perceive to be an easy way out. If Merson has had problems in the past, it shows that he hasn't coped with the pressure he has been under.
"There is going to be pressure in this game and he may feel from time to time that he needs to get away. It's what we call the `fight-flight' reaction. Some people cope with pressure by fighting other people and others fight it by running away from it.
"It is total miscommunication between the two of them about what is expected of them."Reuse content