Economic downturns pose all manner of threats to professionals in the workplace. There's the threat that your employer will go out of business. The threat that you'll lose your job. And the threat that you'll have to take on more work when you already feel like your brain is bursting from its meninges.

All of those risks are easy to anticipate. Less obvious—but potentially even more dangerous—is the threat that a colleague jockeying for job security will try to throw you under the bus, either by scapegoating you for a problem you didn't create or by simply bad-mouthing you behind your back. I've seen it happen, and it's ugly.

Workplace scapegoating is more prevalent when the economy is bad because people go into self-preservation mode as a result of feeling threatened, says Paul Harvey, an assistant professor of management at the University of New Hampshire's Tuck Whittemore School of Business.

"In the workplace, there usually are more challenges and failures during tough economic times, and because of self-serving attitudes, it's common to want to make sure the blame is on someone else," he says. "It's a common human tendency for people to convince themselves that they are the cause of the good things but try to assign blame to others when things go wrong. It's an ego defense mechanism."

Scapegoating is also more common during a recession because bad economic times draw attention to problems and inefficiencies inside companies that might otherwise be ignored during a boom, says Harvey.

"When things tighten up, inefficiencies and problems become bigger issues. You can no longer hide them," he adds.

It's easy to get blindsided by a co-worker playing the blame game, because such subterfuge takes place behind the scenes and because people are so focused on the specter of a layoff that they fail to recognize coworkers' machinations. Thus, a victim of workplace scapegoating often doesn't realize what's happening until his boss calls him into the office for a tense discussion about why the victim's software contains more bugs than the Amityville Horror House.

In such situations, the victim of workplace scapegoating is caught off guard, and his attempt to defend himself may come off as desperate excuses or as an attempt to blame someone else, says Harvey.

So what should you do if you find out a co-worker is trying to throw you under the bus? Harvey says addressing the situation isn't easy because you're presumed guilty of whatever problem you've been accused of creating.