The tragedies are coming one after another. In Binghamton, NY, Jiverly Voong kills13 at the American Civic Association. In Pittsburgh, Richard Poplawski guns down three police officers. In Graham, Washington, James Harrison kills his five children and then shoots himself. All told, 57 people have died in multiple killings in the last month alone.

What's behind the carnage? Could our troubled economy, with rampant job loss and the specter of home foreclosure weighing on our collective psyche, be pushing people over the edge? Or is the answer to be found in the minds of a small number of people who have been quietly gathering rage and losing control for many months or years.

I think the answer is both.

Mass murderers have one thing in common_ They have lost the capacity for empathy. They no longer see others as fully human, so they don't worry over causing them to suffer. They no longer see the life stories of others as sacred, so they don't worry over bringing them to a violent end. I believe this chasm of inhumanity opens because mass murderers have stopped valuing their own lives. They are dehumanized to the extent that depression or paranoia or rage - or all three combined - have displaced everything else inside them-including love, whether for themselves or for others.

The road to becoming a murderer may have its roots in childhood, when abuse and neglect begin to make a child shut down his or her emotions, in order to stop feeling so much pain. That dark psychological process can cast a long shadow, preventing the future killer from resonating with the pain of others. Unrestrained by empathy, it leaves that person freer, in a terrible way, to be violent.

It might well be the case that those who shut down emotionally and begin storing paranoia and rage inside them have less "hearty" or resilient nervous systems. Maybe they have lower levels of serotonin than others among us who would preserve our humanity in the face of equally traumatic events. Maybe they have absolutely no one who is obviously proud of them or shows concern for them or at least shares kind words with them. Maybe they are unlucky enough to have head injuries that erode their capacity to control their emotions and leave them with shorter fuses.

But while the roots of the paranoia and rage that fuel mass killings may run bone deep, today's stresses can set ablaze the deepest cauldrons of emotion. We have among us many, many people who are on the edge psychologically. They do not have reservoirs of self-esteem to carry them through job losses that make them feel like failures - as workers or fathers or husbands. They cannot draw on stores of optimism to believe that things will turn out alright in the end, because things were not alright for them, often from the very beginning. They may already be suffering with depression that can, in some of its forms, lead not only to anxiety and irritability, but also to paranoia and thoughts that life is not worth living. Perhaps they have already turned to bankrupt strategies to keep their emotions at bay, including alcohol or illicit drugs, substances that lower self-control and are involved in the majority of violent crimes.

These are the people who are at risk to become the next Jiverly Voong, Richard Poplawski or James Harrison. They are a job loss, a divorce or a repossession away from utter hopelessness that can tap their underlying stores of self-hatred and hatred for others and lead them to project it outside themselves, in an explosion of violence.

There are many such people in the world. They are victims of life events beyond their control who then victimize others, exponentially. Psychological arithmetic is sometimes cruel: The suffering of one person can multiply itself into the suffering of many.

This economy and these times are dangerous potential triggers. Anyone who says otherwise should sit with me in my office and listen to some of the good and decent people, many from fine families, many with histories of great success, with wonderful potential futures, who can't see any future for themselves, anymore.

Anyone who says otherwise should listen to these "lucky" people, now down on their luck, who irrationally see themselves as permanent failures - not just economically, but personally. Then imagine if you were the product of trauma, with only the most fragile sense of self, thinking the world was already against you. Imagine how a pink slip hits you then. Imagine if it comes with news that your wife is leaving you or cheating on you - with a real man. Imagine if you stop thinking you're a man at all, not even a human being, that everyone is laughing at you, that you're powerless and forgotten and destined for nothing but emptiness. Imagine trying to contain all that.

Some people don't. Instead of containing it and processing it, they project it. Economic chaos makes that outcome more likely. The sooner we stop denying that fact, the sooner we can begin putting in place the needed resources to reach out in a real way to those who think - wrongly - that they are beyond help, and prevent the deaths we can.

Dr. Keith Ablow is a psychiatry correspondent for FOX News Channel and a New York Times bestselling author. His newest book, "Living the Truth: Transform Your Life through the Power of Insight and Honesty" has launched a new self-help movement. Check out Dr. Ablow's website at

livingthetruth.com

or e-mail him at

info@keithablow.com

.

Dr. Keith Ablow is a psychiatrist and member of the Fox News Medical A-Team.