Read: Why do so many graduate students quit?

To make matters worse, the payoff for all that stress may be wanting: A 2014 report found that nearly 40 percent of the doctoral students surveyed hadn’t secured a job at the time of graduation. What’s more, roughly 13 percent of Ph.D. recipients graduate with more than $70,000 in education-related debt, though in the humanities the percentage is about twice that. And for those who do secure an academic post, census data suggest that close to a third of part-time university faculty—many of whom are graduate students—live near or below the poverty line.

A new study by a team of Harvard-affiliated researchers highlights one of the consequences of these realities: Graduate students are disproportionately likely to struggle with mental-health issues. The researchers surveyed roughly 500 economics Ph.D. candidates at eight elite universities, and found that 18 percent of them experienced moderate or severe symptoms of depression and anxiety. That’s more than three times the national average, according to the study. Roughly one in 10 students in the Harvard survey also reported having suicidal thoughts on at least several days within the prior two weeks. (Other recent studies have had similar findings, including one published earlier this year that described graduate-student mental health as a “crisis.”)

The study’s results, which also include survey responses from nearly 200 faculty members, indicate that many Ph.D. students’ mental-health troubles are exacerbated, if not caused, by their graduate-education experiences. Roughly half of the respondents in the Harvard study with anxiety and/or depression had been diagnosed sometime after starting their graduate studies. And students toward the end of their programs were far more likely than those who were just embarking on their graduate journeys to report severe symptoms of anxiety or depression.

Graduate students cite the combination of financial and professional pressures as a significant challenge. Lucy Johnson, an assistant professor of digital literacies at the University of Wisconsin–Eau Claire, says that the financial burdens of her Ph.D. studies made it difficult for her to “escape the graduate curriculum”—by, say, seeing a movie or going out for dinner. Students who already feel isolated by their rigorous academic work are bound to feel even more isolated by their financial troubles, she suggests. Like many of her peers, Johnson eventually took out loans to support herself.

And then there is the academic pressure itself. Graduate education relies on “this idea that we have to produce, produce, produce, or do a lot more labor than others, so we’re worn quite thin,” says Johnson, noting that such labor is often promoted under the guise of “professionalization.” “I think it’s something we’re just supposed to accept as being part of the process.”