ARPS (Advanced Ring Possession Syndrome)
“Thirty students at University College London were asked to explain the odd behaviour the character displayed in the films based on the J.R.R. Tolkien trilogy.
The students noted his solitary habits, spiteful behaviour, odd interests, difficulty in forming friendships, emotional changeability, nervousness and paranoia.”
http://www.reuters.co.uk/newsArticle.jhtml?type=entertainmentNews&storyID=639890§ion=news&src=rss/uk/enter
tainmentNews
( Update: Here’s the BMJ article: http://bmj.bmjjournals.com/cgi/content/full/329/7480/1435?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=gollum&searchid=1103349387213_18575&stored_search=&FIRSTINDEX=0&volume=329&issue=7480 )