Here is the thing about Dennis. He chose to do those things. Dennis choose to get into drugs and alcohol. Mike Love, Alan Jardine, or anyone else did not force him or cause so much stress that they HAD to do it. Dennis was a kickass guy. If he truly didn't like the way that Mike was taking the group, stand up and say enough! And not by punching Mike out at the Universal Amp, but by taking charge of the group along with Carl. Remember too, Jerry Schilling at this time was behind BOTH Mike and Carl and was trying to walk that tight rope. So to say that Mike and Al SO upset Dennis that he started his downward slide gives THEM too much power. Dennis did what Dennis did. As Melcher said, he was what rock and roll bullmerda was all about. And he was. Dennis throwing my PS LP across the lobby of the Hyatt to see if I would bring it back, to "test" me, was just macho bullmerda. And that's ok. But he should have tried to save himself. He could have been such a great artist and producer away from the group. But he blew it. No body else. That makes me really sad too.
Well. Addiction is generally seen as an illness these days. Many stable people get in touch with substances a couple of times and then decide to end it before it is too late. I'd say that the Wilson family bears all the hallmarks of having been predestined to substance abuse, most likely genetically plus traumatic life events. So I am not really inclined to judge him and him only for it. Even if one tenth of all the stories is true (Murry beating him up, or scalding him with hot water), that is enough to create scars and a hidden panic that last a lifetime. Alcohol and cocaine is a typical combination for people who suffer from mood swings. And deep fears. As long as it works, it stabilizes and gives self-confidence. And of course the point in time will come when its efficacy is well and truly over. Basically that is what I think troubled him in his last days.
Why didn't Dennis show signs of mental illness though? The only example I really know of is the recently talked about "Get Down", or whatever it was called. I always thought of Dennis as more of a hell raiser, in regards to his drinking and drug abuse. Brian had more than his share of drugs and booze, but it seems to me that Brian's problems were much more deeply rooted phsychological issues.