Social networking/depression link research

Although I've found it easier to find research about general social networking stats, I've managed to find a couple of articles about the link between over use of internet and depression, loneliness and suicide. The sites I found them on are:

http://www.ocf.berkeley.edu/~stellal/Cons.htm

http://www.dailymail.co.uk/health/article-1132788/Why-chatting-long-Facebook-girl-down.html

The first article deals with social depression, loneliness and depression are linked with overuse of online communities and instant messaging. The second article suggests that teenage girls are more suceptable to depression/anxiety because they discuss their problems over and over again on social networking sites/instant messenger when they are not mentally and emotionally mature enough to deal with such repeated focus on their problems.