Mischa Barton is not crazy.

The Beautiful Life actress says that, although she was placed under psychiatric hold last month, she is not mentally ill -- instead, she says, her little meltdown was the result of wisdom tooth surgery gone bad.

"It was a nightmare," the actress, 23, told Time Out New York. "I've never had surgery before -- it all went wrong and I had to have a second surgery and it almost delayed shooting because it was a nightmare to me, because I couldn't deal with the thought of not getting there on time. So with the travel and surgery and prep for the show, it was hell."

Mischa said she's still in pain -- and the hardest part is that she take the "proper painkillers because I couldn't take those during work."

Uh-huh.

As for being removed from her home by police in July, Marissa Cooper says that it was a whole bunch of things that led to her falling apart.

"I went through a tough spot where everything compounded on me, and it was like a perfect storm, like everything was happening to me at once," she told the mag. "I was down in the dumps about everything there for a while."

She's not calling it an official nervous breakdown, "But it was pretty bad," she admitted. "It didn't last that long... Sometimes you have to hit rock bottom about things and have to get the most stressed out just to feel better again. I got completely stressed out and couldn't handle everything, and now I feel really in control."

Damn dentists! They can ruin your whole life.