People are unique because of the thoughts and emotions that affect the way they react to the world. There’s no such thing as a “correct” personality, whether it’s good-natured or gloomy. But there are such things as personality disorders, a group of mental illnesses classified by dysfunctional ways of perceiving situations and relating to others. People with these conditions are rigid and unwavering in their strange or inappropriate behaviors, to the point where it affects their ability to relate to others and live normal lives.

Personality is formed by a combination of “nature” and “nurture” factors. Traits of temperament such as shyness or friendliness are largely inherited, but how a person grows up also has a big impact. Likewise, personality disorders seem to be caused by both genetic and environmental influences. Research suggests that some people may have predisposed vulnerabilities to developing a disorder, but a traumatic situation—such as an abusive or unstable childhood or the loss of a parent—must trigger its development.

Personality disorders affect about 10 to 13 percent of people worldwide. The American Psychiatric Association classifies them into the following three clusters:

Cluster A: Odd, eccentric thinking or behavior—including paranoid personality disorder (believing that others are trying to harm you), schizoid personality disorder (having little interest in emotional expression or social relationships), and schizotypal personality disorder (believing that you can influence people and events with your thoughts or that messages are hidden for you in public speeches or displays)

Cluster B: Dramatic, overly emotional thinking or behavior—such as antisocial personality disorder (lying, stealing, showing disregard for others, or engaging in violent behavior), borderline personality disorder (having a tendency toward volatile relationships and impulsive, risky, or suicidal behavior), histrionic personality disorder (showing a constant need for attention), and narcissistic personality disorder (believing that you’re better than others and fantasizing about power and success)

Cluster C: Anxious and fearful thinking or behavior—including avoidant personality disorder (isolating oneself and being hypersensitive to criticism and rejection), dependent personality disorder (showing excessive dependence on or submissiveness toward others), and obsessive-compulsive personality disorder (having a preoccupation with orderliness, rules, and being in charge; this is not the same as obsessive-compulsive disorder)

ADDITIONAL FACTS

  1. It’s not unusual to have more than one personality disorder at the same time.
  2. A combination of psychotherapy (talk therapy and education) and medication, such as antidepressant, antianxiety, or mood-stabilizing drugs, is often used to treat personality disorders