A few days ago, a Wall Street executive was debating whether he could get away from the office long enough to see his shrink uptown. In the midst of a busy workday, it was looking unlikely. Then he stumbled across an article in the New York Post with the disquieting news that a J.P. Morgan Chase JPM employee had jumped to his death from the bank’s offices in Hong Kong, just three weeks after a fellow banker at the firm had committed suicide by jumping off the roof of the bank’s London headquarters. “JPMorgan suicide is 3rd mysterious death in weeks,” read the Post headline.

The executive went to his appointment. “He said, ‘That’s what drove me into your office today, I want to make sure that I’m all right,’” says Alden Cass, the psychologist who treats the executive, as well as a bunch of clients who are portfolio managers, investment bankers, and traders of all types.

The rash of suicides has sent a shudder through Wall Street and beyond. The third death referenced by the Post—that of a J.P. Morgan executive director who died inside his Connecticut home in January—did not appear to be intentional. (A report is still pending.) Yet the J.P. Morgan incidents are only the most recent in a string of at least a half-dozen suicides in the financial world since late August. Those include executives at Zurich Insurance Group ZURVY , Deutsche Bank DB , and Russell Investments, among other firms.

Banker suicides aren’t a new phenomenon. Clusters of them in quick succession occurred during the Great Depression and during the recent Great Recession. Indeed, research has shown that suicides can be contagious, so to speak. That is particularly true when graphic and sensational reports of the fatalities lead to copycats, according to the American Association of Suicidology. So the recent untimely deaths have sparked concerns that there could be more on the way. J.P. Morgan spokesman Joe Evangelisti says the company has sent notices reminding employees that 24/7 mental health-related support resources are available at the bank, and that its hearts go out to the families of the deceased.

But with each new wave of suicides come questions about whether the deaths signify a disturbing trend: Is finance a potentially deadly occupation? That is, do bankers kill themselves more often than other people?

To find out, Fortune asked the Centers for Disease Control and Prevention to pull the latest suicide statistics from its National Occupational Mortality Surveillance database. During 1999, 2003, 2004, and 2007—the most recent years during which research was funded and for which data is available—there were 329 suicides among financial specialists, more than in any other occupation tracked by the CDC except for the broad grouping of “engineers and scientists,” a cohort that lost 502 to suicide.

Finance, however, is a vast profession, and while the total number of finance professionals who commit suicide may be larger than for some other professions, they are actually less likely to do so than, say, lawyers or firefighters.

Take J.P. Morgan as an example: At a bank with more than 260,000 employees around the globe, a pair of suicides may seem shocking and random but the figure is, in fact, well within the range of statistical probability. Two might even be a low number. “You would expect that when people work these long hours,” says Alexandra Michel, a former Goldman Sachs GS investment banker turned management professor at the University of Pennsylvania who for 12 years has been tracking the performance and health of a group of Wall Street recruits at two banks (she can’t say which) in an ongoing study. “You would think that it would happen much more often.”

A close examination of the CDC data does reveal a worrisome connection between certain types of financial jobs and an elevated risk of suicide. The CDC organizes its mortality numbers by census categories, which can be pretty broad. The Wall Street-oriented classification is “sales representatives for financial and business services”—a category that includes a variety of banking positions, ranging from investment advisers to brokers to traders to investment bankers. People in that group are 39% more likely to kill themselves than the workforce as a whole. (Members of some other white-collar professions are at even greater risk: Lawyers are 54% more likely than average to commit suicide, and physicians are 97% more likely.)

Within finance, observers say that investment bankers are often under the most acute mental stress. “Out of all the sections of finance, no position do I know of that’s more extreme in terms of the emotional endurance one has to have than investment banking,” says Cass, the psychologist who is also the co-author of Bullish Thinking: The Advisor’s Guide to Surviving and Thriving on Wall Street.

It’s a syndrome Michel has also observed while shadowing investment bankers over the years. After her subjects had worked at a bank for four years on average, she began observing signs of sleeplessness, anxiety, and depression: “I could see how people came in chatting happily on the phone with friends, how that became less and less,” she says. “People became completely absorbed in the office, in work. Some are feeling trapped.”

J.P. Morgan says the two employees who committed suicide weren’t investment bankers, per se. According to their LinkedIn LNKD profiles, Gabriel Magee was a vice president overseeing technology for fixed-income securities in the London office, and Dennis Li was an associate in the billing department supporting the investment bank.

But the high-stakes world of Wall Street has become a more stressful work environment across the board. The 2008 economic crisis and subsequent recession have exacerbated the problem, says Cass, especially now that the new reality of smaller bonus checks, regular layoffs, and heightened regulation has sunk in. While those factors have impacted many professions, Cass says, “In investment banking, it becomes a weed-out process—who can take it and who can’t?”

Cass has noticed the scrutiny weighing on his clients. The anxiety has trickled down from bosses and pervaded the culture, he says, with bankers kept in a “fear position,” worrying constantly about keeping their jobs—or worse, facing criminal charges.

A CDC analysis of suicides by occupation for 2008 and beyond won’t be ready until 2015. But the government agency recently reported an alarming increase in suicides between 1999 and 2010 among Americans old enough to be at the peak of their careers or well-established in the C-suite. Suicides among 35- to 64-year-olds rose 28%, with even larger increases among white people (40%) and those over 50 (more than 48%).

While it’s not fair, warns Cass, to point blame at any one firm or the industry itself, he sees the increased pressure to avoid mistakes as taking its toll on bankers. “Obviously it’s good for the collective health of our financial security in the long run,” he says. For the near term, his clients are keeping their appointments.