As the nation's unemployment rate climbs—it jumped another four-tenths of a percent last month, when employers culled 598,000 jobs—some mental-health experts worry that we may see a corresponding rise in suicides.

Anecdotal evidence of the problem has been around for months, from the suicide of French aristocrat and Madoff victim Rene-Thierry Magon de la Villehuchet to the murder-suicide committed by a laid-off man in Southern California.

But experts have been split about whether suicides overall are really on the rise. Empirically, it's too early to tell, because national statistics for 2008 won't be available for another three years. But given the preliminary data and historical trends, health experts do fear that the recession's toxic mix of stressors—unemployment and home foreclosure—will be reflected in the nation's suicide rate.

Historically, the suicide rate has been linked to the unemployment rate rather than the stock market, investment frauds, or other financial phenomenon, says Dr. Lenny Berman, executive director of the American Association of Suicidology.

During the Great Depression, for example, the peak unemployment rate, 25 percent, coincided with an increase in the suicide rate. As joblessness spread, 17 persons for every 100,000 in the population took their own lives, up from 14 before the Depression. (According to the Center for Disease Control, the suicide rate for 2005, the latest year this information is available, was 11 persons for every 100,000, or a total of 32,637 deaths.)

"Any time there is a significant life stress that threatens the every day functioning of an individual and their ability to cope there is always an increase in the risk of suicidal thinking and behavior," said Dr. Berman.

"In general," he added, "we will expect to see an increased rate of suicide if the recession is prolonged. The Great Depression had a great affect on unemployment and suicide. Subsequent recessions were not as lengthy and did not have the same observable affect on suicide. This current recess threatens to be longer than any recession we've had since the Great Depression."

Calls to the National Suicide Prevention Lifeline in 2008 rose 36 percent from 2007, and employee assistance providers, which offer counseling as part of an employee's health plan, have reported a dramatic increase in calls related to depression and financial concerns.

While those changes occurred as the economy was sinking and unemployment rising, John Draper, director of the National Suicide Prevention Lifeline, said that the increase wasn't entirely due to the financial crisis. Growing public awareness of the line and the expansion of services to veterans contributed to the increase, he said.

Indeed, establishing a clear causal relationship between the economy and deaths is difficult. Mental health professionals caution against extrapolating trends from a few high-profile examples and against assuming that the slump alone—or even primarily—could be responsible for a significant change in the suicide rate.

After all, 90 percent of people who die by suicide have pre-existing psychiatric disorders at the time of their death, according to the American Foundation for Suicide Prevention. But the loss of a job or a home may be enough to push some people into despair.

"Financial crises that affect individuals certainly can act as triggering factors for suicide attempts," said David Litts, associate director of prevention practice at the Suicide Prevention Resource Center. "Usually the people who are affected by financial stress are people who have other underlying vulnerabilities, even though when they're not stressed they function pretty well. But when the crisis hits, they feel hopeless, humiliated, and in despair. They don't have the resiliency that is required to get them through a particularly stressful situation."

Still, Draper reported that the National Suicide Prevention Lifeline does have anecdotal evidence from crisis centers across the country that calls linked to the financial concerns have increased.