In your expert opinion, which GBrs show clear signs of severe mental illness? Are there any members we should absolutely be afraid of or at the very least cautious of engaging?
It's an honor to have you here! 
Wiggs. I would never engage Wiggs in real life. From what I read I think he is on the edge of doing something disastrous in society, to other people and if something wrong is said to him he would go on a shooting spree. Easily the loosest cannon on this site.
Narissistic People on here could be a whole category but some of the obvious ones, the above mentioned Wiggs, Dr. Dutch, jnn, Julio caesar, hipolito meija, army of one, coach is back, this list could go on and on
The mentally ill probably take up 80-85% of the members on this site. Self included