What exactly is a personality disorder? For starters, it’s more than just a “bad” personality. In fact, some personality disorders might seem fun at first glance, especially those that manifest as a flair for the dramatic. Personality disorders share a few common traits. First, personality disorders can be traced back to childhood. We’re born with a personality, which makes us susceptible to personality disorders early on in life. Second, personality disorders are stable over time. They’re persistent and resistant to treatment. Third, personality disorders operate in all situations; they don’t discriminate between work and social functions. Finally, personality disorders cause impairment in social, occupational, and other important areas of life. They prevent those who suffer from them from functioning normally.

Estimates of the prevalence of personality disorders are generally low, but these estimates can be deceiving. People with personality disorders usually don’t know that they have one, so they don’t sign up for research studies about them. It can also be difficult to detect the presence of certain personality disorders without sufficient contact with the afflicted person. In truth, personality disorders are more common than we think. I’d venture to say that each of us will come into contact with at least one person with a personality disorder in our lifetime. My guess is that you already have someone with a personality disorder in your life; you just don’t know it yet.

Many people are exposed to personality disorders in the workplace. Watch for the following signs of a personality disorder the next time that you interact with a coworker.

15. Your coworker suspects you of trying to harm, deceive, or exploit them.

Do you have a coworker who can’t take a joke? Who complains to you about their romantic partner’s infidelity without evidence of cheating? Has your coworker filed lawsuits against people in your workplace over minor disagreements? If you have a coworker who’s highly suspicious of most people, then that coworker might be suffering from Paranoid Personality Disorder. Coworkers with PPD assume that people’s intentions towards them are malicious. They see neutral comments as criticism, and constructive criticism as a personal threat. Expect to be accused of disloyalty by them. Oh, and avoid making them the butt of a joke; I promise you, they won’t laugh.

14. Your coworker isolates themself on a regular basis.

Have you ever had a coworker who you just couldn’t get close to? Maybe you never felt an emotional connection to them, or maybe you couldn’t even find them at the office to invite them out to lunch. Coworkers with Schizoid Personality Disorder aren’t looking for close relationships. They’d rather work alone, so forget asking them to join a work group. You’ll rarely see a coworker with Schizoid Personality Disorder at an office party; it’s not an activity that they take pleasure in. If you try to confide in them about problems that you’re having with other coworkers, they won’t show any interest. You might have better luck interacting with them over the Internet, though, where they can become surprisingly communicative.

13. Your coworker can only be described as eccentric.

Does one of your coworkers dress in a way that’s a little bizarre? Do they say weird things around the office, like speaking in metaphors that only they seem to understand? Do their emotional reactions strike you as inappropriate at times? If so, then you may have a coworker with Schizotypal Personality Disorder. To put it simply, coworkers with SPD are odd. They follow the beat of a different drum. While they’re mostly harmless, they can make people feel uncomfortable in their presence. Try not to make ambiguous statements about them; their paranoia might convince them that you’re trying to sully their reputation in the workplace.

12. Your coworker believes that they have special powers.

Not only is the behaviour of coworkers with Schizotypal Personality Disorder odd, but so are their beliefs. It’s common for coworkers with SPD to engage in magical thinking. I once heard of a person with SPD who believed that she could talk to squirrels. Coworkers with SPD might also hold unusual superstitions, such as needing to clap their hands five times before leaving the office to avoid getting run over by a car on the way home. Some coworkers with SPD might believe that they have a sixth sense; others might argue that they can predict the future, or read people’s minds. Your office psychic might in fact be your office SPD case study.

11. Your coworker lies as often as they breathe.

Picture a coworker who has mastered the art of deceit. They think nothing of lying to your boss about their pivotal role in a group assignment when the truth is that you did all of the work yourself. They frequently disobey workplace rules, even experimenting with pushing the boundaries of sexual harassment from time to time. This coworker never pays the bill when you go out to lunch together. They drink too much at the holiday office party and pick fights with other employees. Welcome to the world of Antisocial Personality Disorder. Be careful around coworkers with ASPD, because they will use you. If you’re lucky, your ASPD coworker will blow off work one too many times and get fired.

10. Your coworker fears abandonment.

Have you ever seen the movie Fatal Attraction? If so, then consider Glenn Close’s character for a moment. Alex Forrest is the poster child for Borderline Personality Disorder. Coworkers with BPD are always anticipating rejection. They’ll cling to you in any way they can to avoid abandonment. They’ll pressure you to hang out with them after work. They’ll disclose personal information about themselves that gives new meaning to the expression, TMI. They’ll begin a sexual relationship with you if they think that’ll keep you close to them. They’ll even threaten to commit suicide to keep you from ending your relationship with them. Try your best not to be seduced by them, or you might find your pet rabbit boiling on the stove when you get home from work one day.

9. Your coworker’s relationships are often unstable or intense.

Coworkers with Borderline Personality Disorder will love you one day and hate you the next. When you first meet, they’ll work hard to become your friend or even your lover depending on which strategy will work best to develop a relationship with you. Not long into your relationship, however, things will start to change for the worse. Coworkers with BPD will suddenly interpret your comments as criticism. They’ll pick fights with you over innocent remarks. It’s no surprise that coworkers with BPD find themselves in and out of relationships at a rapid cycling pace. It’s wise to maintain strict boundaries with these coworkers to avoid unpleasant scenes at work.

8. Your coworker needs to be the centre of attention at all times.

Imagine the following scenario: you’re at your desk in an open office space. Just as you’re beginning to type up a sales report, one of your coworkers walks in, singing loudly, attracting the attention of everyone in the room. Minutes later, a beloved employee announces their retirement. Your singing coworker immediately begins crying, jumping up to hug the retiree affectionately, even though the two have barely exchanged three words since they began working together. Look no further than your office drama queen for an example of Histrionic Personality Disorder. If you’ve been fortunate enough to have a coworker with HPD in your life, then you’ve probably had a few laughs. You’ve watched your coworker get caught up in several inappropriate workplace romances, listened to their dramatic tales, witnessed their opinions change along with the flavour of the month. You may have had lots of fun with this coworker, but you’re likely drained by their constant attention-seeking.

7. Your coworker thinks they’re the greatest thing since Kanye West.

We’ve all had a coworker who holds a grandiose view of themselves. You know, the one who thinks that they’re the exception to the rule; the one who feels entitled to special privileges at work; the one who constantly brags about their achievements, having forgotten the concept of humility. Narcissistic Personality Disorder is quite possibly the most frustrating personality disorder to work with. The NPD coworker’s pursuit of success never stops, even if it means trampling over you in the process. They’re arrogant, envious, and desirous of being envied. Be wary of shattering their inflated sense of self-importance; NPD coworkers will seek revenge by taking credit for your ideas or by disparaging you to your boss.

6. Your coworker avoids participating in interpersonal activities.

Perhaps you’ve worked with someone who just didn’t feel comfortable in social situations. They might have expressed feelings of inadequacy to you, or come across as inhibited during interpersonal interactions. Or perhaps you’ve had a coworker who never answers the phone or speaks up at meetings. They may have demonstrated an unwillingness to participate in a new workplace activity, or eagerly passed off an interpersonal task to you. Coworkers with Avoidant Personality Disorder do what their name suggests: they avoid. They avoid relationships; they avoid social situations; they avoid novelty; they avoid taking risks. At the heart of their avoidance is the fear of disapproval. They dread being criticized or rejected, so it might be a good idea to offer them some reassurance once in a while.

5. Your coworker is uncomfortable with working alone.

Have you ever felt suffocated by a coworker, as if you couldn’t get rid of them if you tried? Have you ever referred to a coworker as a stage five clinger? Have you worked with someone who needed constant reassurance before making a decision? Have you ever found yourself taking on work for a coworker, work which they insisted that they couldn’t complete alone? If you answered yes to any of these questions, then you may have been the victim of a coworker with Dependent Personality Disorder. Coworkers with DPD feel helpless, and seek out others to reduce their feelings of helplessness. They’ll bend over backwards to please you, as long as you offer to take care of them in return. Just don’t take advantage of their apparent kindness; they’ll feel resentful if you do.

4. Your coworker’s perfectionism gets in the way of completing tasks.

You may have worked on a project with a coworker who needed things done a certain way. They may have insisted on following a strict schedule to complete the project, or become obsessed with the appearance of the handwriting on the project report. They may have seemed inhumanly organized to you, down to the last detail. Coworkers with Obsessive-Compulsive Personality Disorder don’t practice compulsive rituals like their OCD counterparts, but they’re inflexible in others matters, particularly when it comes to their work. They want things done their way, even if their way isn’t the best approach to completing a work assignment. They follow workplace rules almost blindly, coming across at times as more robot than human. It can be hard to reason with an OCPD coworker when they’re caught up in their perfectionism, so it might be best to assign a task to them and let them carry it out on their own terms.

3. Your coworker lacks empathy.

A lack of empathy is a hallmark of several personality disorders. Coworkers with Narcissistic Personality Disorder, for example, routinely ignore the needs and feelings of others in pursuit of their own success. Coworkers with Antisocial Personality Disorder fail to show remorse for mistreating others, while coworkers with Schizoid Personality Disorder appear dead to emotion altogether. While coworkers with other personality disorders may not be incapable of showing empathy, they’re unlikely to do so unless it satisfies one of their needs (for example, a coworker with Histrionic Personality Disorder might show empathy to get attention). Personality disorders are all consuming, and leave no room for thoughts of other people’s problems.

2. Your coworker thinks you’re the problem, not them.

If you have a coworker with a personality disorder, then chances are that they don’t see anything wrong with themself. Coworkers with personality disorders don’t recognize that they’re a problem in the workplace, and consequently see no need to change their behaviour. Sometimes, coworkers with personality disorders see their traits as virtues. Take Obsessive-Compulsive Personality Disorder, for example. A coworker with OCPD may see their excessive attention to detail as an asset in the workplace rather than a hindrance. It can be difficult to get a coworker with a personality disorder to see reason, especially when psychologists don’t have much luck accomplishing this themselves.

1. Your coworker has never heard of boundaries.

Coworkers with personality disorders have a hard time recognizing boundaries, which means that they cross them regularly. Coworkers with Borderline or Histrionic Personality Disorder might make inappropriate sexual advances at work, or overshare personal details about their lives with mere acquaintances. Coworkers with Antisocial Personality Disorder might break office rules or violate social norms. Coworkers with Dependent Personality Disorder might beg others to assume responsibility for their work. Because coworkers with personality disorders have trouble respecting boundaries, it’s extremely important to enforce boundaries whenever you’re interacting with them. That way, you can avoid getting sucked into a mess at work.

Sources: DSM-5