Women who identified as being attracted to both genders fared worse in other indicators as well, including a diagnosis of depression, according to the paper published in the Journal of American College Health.
The analysis was based on a health survey given to some 150,000 college women across the country for three semesters in 2008 and 2009.
Santurri and her co-authors, Dianne Kerr and Patricia Peters of Ohio's Kent State University, chose to study college lesbian and bisexual women because relatively few examinations of mental health and the lesbian, gay, bisexual and transgender (LGBT) population have focused in on those subsets.
Though the results are generally in line with other work on the topic, the sharpness of the disparity between lesbian and bisexual women was surprising for Santurri, and could give guidance for crafting policies, treatment and intervention.
"A lesbian woman might be very, very different from a gay man, who might be very, very different from a transgender individual," she said. "Not everyone in the LGBT population is going to be similar."
The survey, distributed by the American College Health Association to many universities, didn't ask about underlying reasons for the mental health issues it identified, which included feelings of overwhelming anxiety, anger, hopelessness, loneliness, sadness and depression.
"We have these numbers, but our data doesn't exactly tell us why," said Santurri, though "the evidence suggests discrimination against the LGBT community is a big driver for the mental health disparity we see in this population."
LGBT people are more likely to have been discriminated against or bullied, Santurri said, and bisexual people in particular have an orientation that often isn't well understood by the public.
"We all have a sexual identity and we all have a gender identity," Santurri said, "but for some of us our identity makes us less likely to have the same rights as others."
The findings, which were drawn from a sample of 6,700 people, came from a time when the country was in the throes of a debate over Prop. 8, which banned same-sex marriage in California. That law has since been struck down and other states have legalized gay marriage. Could those changes and others improve mental health outcomes?
"I certainly hope so," Santurri said. "We have to continue to do research to monitor those outcomes."
She plans to investigate the experiences of LGBT students at Weber State next semester. Her "PhotoVoice" approach will include a series of questions and digital pictures reflecting students' feelings about the answers. After a daylong workshop to discuss the stories and pictures, the data will go to the university to "potentially make changes" at WSU, according to a school statement.
An exhibit of the photos will go on display in April.