Found this article about internet trolls thanks to Stephen Fry, who tweeted it.
Internet Trolls Are Narcissists, Psychopaths, and Sadists | Psychology Today

"So next time you encounter a troll online, remember a few things. (1) These trolls are some truly messed up people and (2) it is your suffering that brings them pleasure, so the best thing you can do is ignore them. " I'm not keen on a psych article referring to people as "truly messed up"

Just discovered the author is a computer scientist, but still....
Here is her follow up article
http://www.psychologytoday.com/blog/...internet-troll

Here's one about bipolar disorder and poor online social interaction
http://www.psychologytoday.com/blog/...al-interaction