Robert O'Ryan

Shawn Johnson's obsessed fan is now officially a felony stalker -- and the just has just found him mentally insane. Robert O'Ryan -- who went looking for Shawn last year with two guns in his car and then broke into the set of "Dancing with the Stars" -- was also found guilty of carrying a loaded…

Shawn Johnson's alleged stalker Robert O'Ryan is insane ... this according to the guy himself. O'Ryan -- who's facing charges of felony stalking, felony commercial burglary and two misdemeanor counts of carrying a loaded firearm in his car -- plead not guilty by reason of insanity in L.A. County…