Why the original drummer of blink-182, Scott Raynor, left the band?

Scott Raynor was the drummer of blink-182 since its debut in 1992/1993. He followed the band into the creation of "Buddha", "Cheshire Cat" and "Dude Ranch". After this last album, Scott Raynor left the band and was replaced by Travis Barker, former member of "The Aquabats". Lots of rumors have been circling around the net on the why and how Scott left the band, and the silence of the singers (Mark And Tom) on this subject contributes in their growth.

Some days ago I read a post on Reddit (which was been written 4 years ago!) where the brother of a girl who dated Scott (at the time that he was playing on the band) gave a really nice explanation.

When someone posted the "Josie" video on Reddit, a guy named skunkwrxs replied saying:
This song was written by Scott (The Drummer at the time) about my sister. Random I know.

EDIT: I was asked for proof (Which I would want as well), here is what I have with me. http://imgur.com/a/CYcHo
After this, another used asked for more information about this. This is his answer.
She dated Scott starting from the Cheshire Cat days (I think it was 1995) into the period where things got rocky with he and the band. (Post Dude Ranch) Scott was an extremely great guy, with some flaws. But it didnt stop him from being incredibly kind and thoughtful to me, the little brother. He would even call me from the road just to be nice. Everything fell apart at about the same time he left the band. It all just got to be too much, we all wanted him to desperately get some help, but he was stubborn. I still miss him to this day. He and my sis shared the exact same birthday and ironically enough both went into non profit work after they split up
Another user asked for a clear story on what happened when Scott left the band. This is what he answered.
I will tell you everything I know, and of course I wish to remain respectful to Scott, he was honestly, a fantastic, kind person. Scott started to drink more heavily as their success grew, and it started having impacts on his ability to perform. (I believe at one point he was so drunk he threw up on his drums during a show). Then he and my sister started having issues with their relationship, adding additional strain. I won't say exactly what it was, but something occurred that was pretty serious with his family back home, which really caused things to spiral. From what I remember one of the turning points was when he became extremely intoxicated and threatened to jump out of a second or third story window after a show one night. Everyone begged to him to back in, but he either jumped - or fell out of the window and shattered his heels in the fall. Once that happened he couldn't play, and Travis filled in for a show. He came back and performed for a short period, in which the pressure on him to get sober became extremely heavy. Now the details of how they asked him and what he said are somewhat in dispute. I have heard they called him and asked him to stop and he agreed, but they moved to replace him anyway, I have also heard he flat out refused. I am not sure which is the truth to be honest. But either way, it led to the collapse of their long time friendship and he leaving the band. During this time, he and my sister were engaged and she was also begging him to get help. So he lost his spot in the band, had the engagement collapse about the same time. It was a very sad time. My family and I all still miss him dearly, and we absolutely wish him the best. From what I understand he really found his niche in non profit work for at risk teens and that he doing really well. So that's what I know, tough to write.
You can read the entire post right here, but all the interesting content is posted above.
Besides this, this is what Scott himself had to say about his explusion from blink-182:
I think the greatest misconception was that I was fired for drinking. I received a phone call from Mark, Tom, and Rick (manager), one afternoon after a recent tour. They gave me an ultimatum to quit drinking and go into rehab. I didn't think I needed to go to rehab so I asked for the weekend to think about it, they agreed. I went out and got drunk. After that weekend I realized that I had a drinking habit that I needed to break, I told them I would go to rehab and they said they didn't trust me. So I asked if there was anything I could do to stay in the band and they said no. So I was never given a reason. Another misconception is that I am somehow upset or bitter about this. When they said they wouldn't trust me to quit drinking I realized that I was not in the company of friends. And I wouldn't have wanted to be in a band whom are not my friends."