"A lot of times schizophrenia doesn't show symptoms until you're in your early 20s. You might have a 'normal life' up until then and then you have a psychotic break," Simpson said. "I think depression and anxiety probably show their face earlier in life."

When Johnson was just 2 years old, her mother nearly died giving birth. The baby didn't make it. Unable to cope with the loss, Johnson said her mother couldn't take care of her for a while. She started thinking her mom didn't like her.

"We didn't hug or anything until after the overdose," she said.

Doctors had to give Johnson massive doses of steroids to save her life. She said she developed a bone disease called avascular necrosis as a result and has had to undergo 13 bone surgeries. She moved to Sioux City from Cherokee, Iowa, a few years ago with a roommate and friend.

"I've been doing better," she said. "Just recently I've had a really bad depression that won't go away."

Her doctor prescribed lithium, which leaves her feeling shaky, nervous and lightheaded. It's one of 14 different medications she takes daily.