When people are “difficult” to be around, it’s easy to toss off labels like sociopath or narcissist—especially if the person seems to be totally full of themself or have no remorse for the way their actions might affect you. But while they share some similarities, sociopathy and narcissism are two distinct psychological disorders. Understanding them may make it easier to deal with someone who seems to be one or the other.

Sociopaths and narcissists: what they have in common

“Both sociopaths and narcissists have personality disorders, meaning that certain personality traits are so extreme that it causes harm to themselves or others, or causes multiple losses and failures in life, such as losing jobs or important relationships, or failing in school,” Aimee Daramus, PsyD, a Chicago-based licensed clinical psychologist, tells Health.

People with both disorders value themselves above others, can’t step outside their awareness of what they want and need, and consider others’ feelings as secondary or a non-issue for them. They can also be charismatic and charming. But those traits are coming from different psychological places and for different reasons.

Traits all narcissists share

“A narcissist is essentially somebody who is self-­obsessed to an extreme degree,” Darrel Turner, PhD, a forensic psychologist in Louisiana, tells Health. “This is someone who has a high level of confidence and belief in themselves, but to a very unhealthy and harmful extent—to the point at which it actually distorts their sense of reality about themselves, other people, and the world around them. It can also lead them into manipulative and exploitative behaviour because they will prioritize their own needs above anyone else’s.”

That definition can seem broad, especially with the #selfie generation and in today’s cutthroat work culture. But people frequently misuse the term narcissist. “Just because someone is ‘full of herself’ or takes advantage of others doesn’t necessarily mean they are a full­-blown narcissist,” says Turner.

To be diagnosed with narcissistic personality disorder, according to the Diagnostic and Statistical Manual of Mental Disorders V, someone would have an exaggerated sense of self-appraisal, set goals based on gaining the approval of others, set unreasonable high personal standards, lack empathy, be antagonistic, demonstrate feelings of entitlement, make excessive attempts to attract and be the focus of the attention of others, and firmly hold to the belief that they are better than others. It’s not a phase or a mood; it’s a lifelong disorder.

Above all is the narcissist’s need to be the most important, Daramus says. “That usually comes out of insecurity, but occasionally you get it coming out of a place of privilege, from someone who has genuinely never been exposed to the idea that other people matter,” she says.

What drives a sociopath

Sociopaths—people who are actually diagnosed with antisocial personality disorder—have many narcissistic characteristics, but this psychological disorder is typically much more dangerous. “Whereas a narcissist may occasionally harm people as a consequence of their self­-prioritization, the harm they cause to others is usually unintentional,” explains Turner. “More often than not, it’s a consequence of their self­-obsession rather than the motivator which drives them. A sociopath, on the other hand, essentially ‘gets off’ by hurting other people.”

That doesn’t mean every sociopath is a serial killer. “It’s actually more common for a sociopath to be driven by a need to control and manipulate other people, to damage them in some way, and to gain money and power,” Turner says. “They are more likely to be in a parasitic or controlling/abusive relationship with a romantic partner; to engage in risky activities like drugs, problematic gambling, and promiscuous sex; to backstab and sabotage their colleagues at work; and to carry out financial fraud schemes.”

Someone with APD, according to the DSM-V, is egocentric, acts based on personal gratification, lacks empathy, is incapable of intimacy, and is manipulative, deceitful, callous, risk-taking, and impulsive. “A sociopath is someone who, on a biological level, is lacking awareness of others’ feelings, and isn’t all that interested in anybody else’s rules,” says Daramus. “They’re far more charming and exciting than most narcissists, whose charm is more superficial. Because of the lack of empathy, sociopaths feel little or nothing when they hurt or take advantage of others.”

Sociopaths are especially dangerous because they often go to great efforts to hide their true personality and appear likeable, adds Turner. A true narcissist, on the other hand, often doesn’t—and couldn’t—try to hide what they are.

Given their psychological makeups, it’s unlikely that someone diagnosed with a narcissistic personality disorder or antisocial personality disorder would think they need or ever seek help. If you suspect you’re dealing with someone who may have either disorder, don’t get swept up into their worldview—and make sure to watch out for your own interests.