Here's an except from an interview with David Gerrold about his time working on Star Trek: The Next Generation and the problems he ran into while working with creator Gene Roddenberry:
“Well this is something we don’t like to talk about. Gene gave us Star Trek and he was a great visionary in that regard. But he didn’t know how to share the credit with everyone else and he was self-centered. And that led to some serious mistakes, and one of them – and I have no idea why – but he was a substance abuser. First it was alcohol, and then it was grass, and then it was Quaaludes and other drugs. He had this disease. If he had stayed off the booze and the pills, he would have been going strong until ninety. He was just a big strong guy, but he fell into that trap of substance abuse and it killed him. We could see that breakdown in his thinking processes very early. Maybe the stress of producing was tough on him. I didn’t know him that well personally, I only knew that professionally that there was stuff going on with him …
Well that came from Gene’s lawyer [Leonard Maizlish], a scumbag of a human being. I cannot say enough things – he was a truly evil human being. He was going to be Gene’s helper on the show. He appointed himself Chief of Staff and he would go around and say we can’t do this and we can’t do that and ‘on Star Trek everybody loves each other.’ For those of us who had written for the show knew that wasn’t true! We knew our people got into arguments. But what happened was he would go to Gene and say 'you can’t let David do this and can’t let Dorothy do that.' Everybody has to be good friends. It is that whole ‘band of brothers’ thing we established in the first. Well, no. What we established in the original series was that there was a lot of tension between Kirk, Spock and McCoy. It is normal and appropriate. Yes, there should be tension between these people who have different jobs. But you get Leonard Maizlish wandering the halls telling writers ‘you can’t do this’ and everybody is terrified because you could argue with Leonard and explain to him and the next thing you know you get a memo from Gene that was dictated by Leonard.
I had it happen to me several times where I would talk to Gene and explain that I thought ‘Data’ was a bad name for the android and Gene would say ‘you are probably right, come up with another name.’ And we would come up with another name and the next thing -- later that afternoon -- Gene would say 'no, I’ve talked it over with my lawyer, we will keep the name Data.' Another time I would say we should do so and so and he would agree and then later in the day Gene would say 'I’ve talked to the lawyer and we have to do it this way instead.' And I was ‘why does a starship need a lawyer, Gene?!’ That was the control that the lawyer had. Gene was terrified that the studio would try and take the show away from him, so we ended up with this bizarre circumstance that Gene was so afraid of losing his show that he gave control away to his lawyer and he didn’t trust me or [original writer and associate producer] Dorothy Fontana after. That was the part that hurt Dorothy and I the most is that Gene stopped trusting us and started treating us as the enemy. The result of that is that I am not going to fall into the ‘Gene was the Great Bird of the Galaxy’ bulls--t that everybody loves to share, because I saw Gene being something other than the Great Bird of the Galaxy.”