Trichotillomania is an extreme form of anxiety that causes one to pull out hair from the scalp, eyebrows or eyelashes, possibly leaving bald spots, according to the Mayo Clinic.
"For some people, hair pulling is intentional and focused. They're aware that they're pulling their hair out and may even develop elaborate rituals for doing so. Other people pull their hair unconsciously," the Mayo Clinic said.
"I don't bite my nails, but I rip out my eyelashes," the 32-year-old actress told the New York Daily News. "It doesn't hurt, but it's really annoying. Every time I run out of the house, I have to stop and pick up a whole set of fake eyelashes."
Munn who is dating "The Killings" actor Joel Kinnaman, 32, also has a social anxiety disorder, MSN.com reported.
"I don't think anyone would describe me as weak, but I don't want people to be mean to me," she said. "As an Air Force kid, I moved around a lot when I was younger and no one was nice to the new kid. So there is always this feeling that someone will make fun of me."
Her bio on the IMDB mentions her moving around as an "Air Force kid." "Oklahoma-born Olivia Munn, daughter of Kim and Sam Munn, grew up in a family of five children. She was 2 years old when her mother remarried an Air Force man. After that they left Oklahoma and moved around a lot."
Munn's career has been on fire lately, after scoring roles in "Magic Mike," HBO's "The Newsroom," and "The Babymakers," which will be hitting theaters Friday.
In the new movie she plays a wife who is so desperate to have a child she encourages her husband to steal from a sperm bank. The IMDB says, "After failing to get his wife pregnant, a guy recruits his pals to steal the deposit he left at a sperm bank years ago."
But in real life she's in no rush to get pregnant. "I definitely don't have a baby urge right now," she told the Daily News. "Having a baby is like losing your virginity; once you do it, you can't take it back. That baby is forever."
Just because Munn suffers from anxiety disorders doesn't mean she doesn't like to kid around. On her Twitter page she calls herself "Olivia Munn: vigilante super hero, novelty pen collector and your mom."
Munn explained that she doesn't want her recent success to flounder, so she is trying to keep in touch with actors she has worked with recently.
"I'm aligning myself with people like Jon Stewart ("The Daily Show"), Aaron Sorkin ("The Newsroom"), Steven Soderbergh ("Magic Mike") and Paul Schneider ("The Babymakers") so that this recent success won't be temporary."
"I know how lucky I am, but I won't allow myself to get sucked in by all the talk. Talk is just for a moment," she told the Daily News. "This career has to last for a long time."
Munn has immersed herself into her work, and she's happy that way.
"People tell me, 'Your work won't keep you warm at night.' But it does pay for my heat and my down comforter, so it technically does."