Her finalist year: 2000

Her finalist project: Developing a new way to control weeds

What led to the project: Helen Wiersma grew up in the 1980s and '90s in Okeechobee County, Fla., where her family owned a cattle ranch. One day she was out in the pasture riding around with her grandfather when she saw him take out his shovel to dig up a noxious weed called the tropical soda apple.

"I was like, 'Grandpa, why don't you just spray it?' But he told me couldn't afford to do it," she says. The available herbicides were expensive and didn't reach the roots of the plant anyway.

So Wiersma decided to see if she could invent a better way to control these weeds. As a high school freshman she started doing research at the University of Florida's Institute of Food and Agricultural Sciences's Southwest Florida Research and Education Center, about two hours from her home. Her father, grandfather and uncle took turns driving her there and back until she got her license.

But all that commuting paid off. She figured out that by combining very small amounts of traditional herbicide with an opportunistic bacterium called Erwinia carotovora, she could damage the tropical soda apple enough that the bacteria could then attack the roots, and hence control it more effectively than herbicide could alone. She entered her project in the 2000 Intel Science Talent Search and was named a finalist.

Wiersma was thrilled to do so well. "I never thought someone from a little rural hick town could actually compete with the bigger city high schools," she says.

The effect on her career: She went on to earn a double major in biology and chemistry at Sewanee: The University of the South in Tennessee, and spent her summers interning in the infectious diseases research division at Merck, the pharmaceutical company.

All this research just cemented her love of hands-on science. "Science is really one of those disciplines that when you discover something, you're the first person who's ever seen that. I found that really cool." She decided to go to Stanford University for graduate school after her 2004 graduation to continue her research.

What she's doing now: These days, Wiersma is in her fifth year of a biochemistry PhD program, studying enzyme evolution—that is, how different proteins achieve specificity for different reactions. She plans to finish in two years, though it's been a tough journey.

During her second year of grad school, Wiersma fell into a severe, yearlong depression. Multiple antidepressants didn't help, and she had to be hospitalized. She had no idea what was wrong with her.

Then, about two months after she recovered, she had her first manic episode and "everything clicked," she says. "It was a relief, actually. I knew what was going on." Doctors diagnosed her with bipolar disorder, a disease that affects around 4 percent of Americans to varying degrees, and is characterized by dramatic and often debilitating mood swings, with periods of normalcy in between.

But just because Wiersma had a name for her disease didn't mean that she was in the clear. Over the past three years, she's had to take about a year and a half off of school, often in two- to three-month chunks. "I'm usually involved in some kind of hospitalization or outpatient program until I get stabilized again," she says.

She's currently taking multiple medications and is in therapy to help her identify both when she's going to experience an episode and how to manage its severity. The combination seems to be working; when she experienced a bout of depression a few weeks before being interviewed for this article, she managed to stay out of the hospital and maintain functionality.

Needless to say, continuing to do her research while battling bipolar disorder has been difficult. But "my advisor has been 100 percent supportive of me coming back after each of these times," she says. And so, she keeps plugging along, and is also doing her best to raise awareness about mental illnesses. At Stanford, she wants to "bring it out into the mainstream so it's not hidden. For a long time I felt very shameful of it, but I've come to realize it's nothing to be ashamed of. This is a physiological condition." Although she wishes she didn't have the disease, "everyone has their challenges in life. This just happens to be mine."

And so, just as someone with a chronic condition such as diabetes might fully expect to finish a PhD, "I plan to pursue a career in academic science," Wiersma says. "There's no reason I shouldn't be able to do that."

That's a reasonable expectation, says Carlos Zarate, chief of the mood disorders research unit at the National Institute of Mental Health. "People can live productive and functional lives," he says, particularly if they stick with their medications and therapy. For instance, he recently heard from a former participant in a clinical trial who'd just finished a degree and was doing well. It's not realistic for all individuals, "but for many it is possible."