My coworker, however, keeps going out of his way to make me look bad. Without going into every gory detail, let me just say that he has told outright lies about me to higher-ups, deliberately withheld crucial information so I looked like an idiot, cast the blame on me for his own mistakes, and spread rumors that have turned other team members against me. I tried speaking with him about all this, as you recommended recently, but it was like talking to the wall. I’ve also tried to set the record straight with our boss, but this person has charmed everyone around here, so I’m the one who sounds paranoid if I try to describe what he’s doing. Do you have any ideas about what else I can do to stop this? — End of My Rope

Dear E.M.R.: Yikes. I’m sorry to say that the short answer is you probably can’t stop it. Competition among peers has been known to bring out the worst in people, and many workplaces unfortunately have a garden-variety bully or two. But the kind of sneaky, malicious, win-at-any-cost tactics you describe are symptoms of a condition the American Psychiatric Association calls narcissistic personality disorder (NPD).

As you’ve found out when you tried to talk to this colleague, “reasoning with narcissists doesn’t work, because they are not reasonable people,” says Joseph Burgo, a therapist who wrote a book you might want to check out, The Narcissist You Know: Defending Yourself Against Extreme Narcissists in an All-About-Me Age.

“Sinking to his level and trying to use the same tactics back at him won’t work either,” he adds, “because it will just escalate the conflict. Narcissists will stop at nothing to ‘win,’ so if you turn it into open warfare, he’ll always bring the bigger gun.”

The word “narcissist” often gets tossed around colloquially to refer to anyone who seems egotistical or self-absorbed, and it’s possible to have one or two out of the nine traits that characterize clinical narcissism—a craving for admiration, say, or a belief that one is uniquely gifted and destined for great things—without ever developing full-blown NPD.

“Narcissism is a continuum, like a bell curve, and we all land somewhere on it at some point,” notes Burgo. But narcissistic personality disorder, including an almost total lack of empathy and a pattern of ruthlessly manipulating other people, afflicts only about 1% of the population. Says Burgo, “It’s actually the opposite of true, healthy self-esteem.”

The Narcissist You Know details several harrowing case studies of people who sound an awful lot like your terrible colleague. They most often get that way as a result of severe childhood trauma that has left them with the unconscious fear that they are “small, defective, and without value,” Burgo writes. By the time they grow up and start vying for promotions at the office, it’s way too late to undo that early damage. Extreme narcissists’ behavior, incomprehensible to people used to playing by the rules (like you), is an attempt to protect themselves from ever again feeling like a “loser.”

Sad as that is for your colleague, it’s sad for you too, because there is probably no way to come out ahead here. “What is really dangerous is that he has everyone else fooled, including your teammates and your boss,” notes Burgo, adding that isolating their victims from potential allies is a classic narcissistic strategy. “His ability to charm the right people, so that no one will believe you, indicates that he knows exactly what he’s up to—and exactly how to hide it.”

You may be able to protect yourself to some degree, he adds, by “documenting everything. Keep a precise record of every incident, every deliberate omission, every toxic email. This way, if he sets his sights on something extreme like trying to get you fired, it won’t be just your word against his.”

But in the end, your best bet is probably to start looking for another job, either within your company or elsewhere. Let’s suppose he gets the promotion. Do you really want him as your boss?

Or let’s say you’re the one who gets the bigger job, despite his underhanded efforts. “That could just escalate the problem, because extreme narcissists never acknowledge defeat,” Burgo says. “And the competition is never over.”

Good luck.

Talkback: Have you ever encountered an “extreme narcissist” at work? How did you deal with it? Leave a comment below.