The inflation of a name used in your vocabulary when talking; usually at the beginning stages of dating someone. Mentionitis is when you can't stop mentioning someone.
H: "These are great cookies"
S: "Matt likes cookies"
H: "So I was looking at something online..."
S: "I got a cool link from Matt, lets check it out."
S: "Matt blah blah blah Matt Matt Matt"
H: "Whoa you have a strong case of mentionitis"
giving away the fact one has a crush by frequently mentioning the crush object in an "innocent" context.
Mentionitis as a warning sign:
"Boyfriend: let's go see Movie X
Girlfriend: Oh, Tony from the office saw that and liked it!
Boyfriend: How about pizza?
Girlfriend: sure, i saw Tony from the office having slice and am now craving one.
Girlfriend: I am leaving you for Tony from the office"
The disease of constant obnoxious name-dropping etc.
Katie: Yo, I was just at Manhattan Beach yesterday...it was so nice.
Wes: Oh yeah, I went there last week with a friend who parties with Eddie Van Halen's drug dealer....
Katie: Ewww. You're hideous.