Lack of empathy is the most common feature of psychopaths. "They are people who act recklessly or without sympathy towards others, which often results in chaotic or superficial relationships," says clinical psychologist Devon MacDermott, Ph.D. over email. A study published in the journal Frontiers in Human Neuroscience looked at the brain activity in psychopathic people, and it found that psychopaths do not experience empathy when imagining the pain of others. Even worse, they possibly take pleasure in it.

"Given the lack of emotional awareness and impulsive tendencies, the individual can be volatile," says Manly. "As a result, anger may manifest through irritability and aggressive fights, especially when the individual feels frustrated. As a result, the individual may tend to erupt into a fight or angry outburst when a desired outcome is not achieved quickly."

"Frequently, they can be impulsive and reckless, jumping into dangerous situations while ignoring the consequences," says psychiatrist Dr. Susan Edelman over email. This isn't the kind of impulsivity that is adventurous or spontaneous. Instead, it's considered "dysfunctional impulsivity," which is characterized by erratic disorderliness, distraction, and inaccurate decision making, according to the American Psychological Association.

"People with psychopathic tendencies tend to be adrenaline junkies and will seek stimulation in dangerous ways including risky sexual behavior, activities that could cause bodily harm, or illegal activities," says MacDermott. They are prone to boredom, so they are always looking for stimulation.

A psychopath will display patterns of deceiving and manipulating others for profit or even personal amusement. "People with this severe type of personality disorder lack a sense of inner right and wrong," says Edelman. "They don't seem to care about another person’s feelings, so it doesn't bother them to manipulate or deceive others for their own gain. They might trick you with charm, intimidation, or violence."

"Psychopaths tend to be habitual criminals, or they engage in non-criminal behaviors that are generally regarded as unethical, irresponsible, immoral, or in violation of social expectations and norms," says Manly. According to a study published in the journal Legal and Criminological Psychology, psychopaths make up as much as 25 percent of male offenders in federal correctional settings, even though they only account for 1 percent of the general population.

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Don't be fooled by someone's apparent sweetness. "People with psychopathic tendencies can appear gregarious, funny, and charming, at first," says MacDermott. "However, they do not have the genuine warmth and caring to support long-term relationships. They tend to be charming to get what they want from people, not because they actually care about investing in others."

Deeper emotions such as kindness, empathy, compassion, sorrow, remorse shame, and guilt are foreign to the individual who is considered a psychopath, according to Manly. "Shallow, more easily accessed feelings, such as anger, rage, and frustration are often much more accessible to the individual," she says. "The person with ADP may, at times, be able to feign a deeper emotion, but this would be done only on a temporary, superficial level in order to achieve the desired end result."

A person with Antisocial Personality Disorder has a hidden agenda. "Although comments may sound kind and benevolent, the underlying intention is personal gain," says Manly. "For example, a comment such as, 'You are the most beautiful woman!' would be intended to flatter to achieve a personal goal (sex, theft, etc.) rather than being a sincere, heartfelt comment with no secondary gain involved."

Rather than taking responsibility for their actions, psychopaths evade accountability by casting blame on others. "For example, rather than saying, 'I’m sorry that I took your wallet, that was simply wrong of me,' the comment might be, 'I don’t know how your wallet ended up in my closet. You are so forgetful — you must have put it there,'" says Manly.

Individuals who possess a psychopathic personality usually are narcissistic, arrogant, and dominating. "This population tends to have an exaggerated sense of self-worth and self-importance," says Marc Romano, Psy.D over email. Because of this, they also show a sense of entitlement.

As part of their manipulative personalities, psychopaths tend to be pathological liars and and masters of deception. "Lying is key to their existence and when caught in a lie, the psychopath will double down," says Romano.

"Impulsive behavior and sexual promiscuity are common among this population," says Romano. Because their personality traits prevent them from having healthy relationships, their sex life is often not healthy either. Research shows that psychopaths tend to have many short-term relationships, but they exhibit promiscuous sexual behavior.

People who fall into the category of psychopath often have an inability to plan for the future, according to Psychology Today. They fail to set realistic, long-term life goals, and they are carefree about not having any of these plans.

Psychopaths take advantage of others to get what they need out of them. "This can also be referred to as a 'parasitic lifestyle' in which people will persuade or force others to meet their every need without offering anything in return," says MacDermott. "It's an exaggerated version of the person who sleeps on your couch and eats all your food, but never offers to contribute anything to the household and doesn't search for a job."