She obviously had become an alcoholic, based on her Twitter entries and numerous reports on major golf message boards. Las Vegas is a horrible city to live in if you have that weakness. With one exception, every Las Vegas friend or acquaintance of mine who died young was an alcoholic.
I'm convinced that alcohol played a part in Erica's death, probably an accidental death of alcohol mixed with drugs, perhaps Zolpidem. Her last reported activity was playing golf with a friend on Friday. She was found dead on Sunday afternoon. That leaves Friday and Saturday, the two major party nights particularly in Las Vegas. I think she was in no position to travel and therefore sent the wee hour text message to her caddie, saying she wouldn't make it to Alabama for Monday qualifying. Then once you back out of the trip, it's like a relief, and an excuse to drink some more.
Here are two links from one of the best golf blogs, one showing Erica last year, during the period it was obvious she had a problem. The second is a tribute including many pictures and anecdotes courtesy of her regular caddie:
http://www.weiunderpar.com/post/195431750/erica-blasberg-is-like-so-what-im-drunkhttp://www.weiunderpar.com/post/615398001/the-girl-who-could-floor-you-with-a-grin