Personality disorders are long-lasting, pervasive patterns of thinking, perceiving, reacting, and relating that cause the person significant distress and/or impair an individual’s ability to function.
Causes of Antisocial Personality Disorder
Genes and environmental factors (such as adversity during childhood) contribute to the development of antisocial personality disorder.
Antisocial personality disorder is more common among first-degree relatives (parents, siblings, and children) of individuals with the disorder than among the general population. Risk of developing this disorder is increased in both adopted and biologic children of parents with the disorder.
If children develop conduct disorder and attention-deficit/hyperactivity disorder before they are 10 years old, they are more likely to develop antisocial personality disorder as adults.
Conduct disorder involves a repetitive pattern of behaviour that violates the basic rights of others and/or age-appropriate societal norms. Conduct disorder may be more likely to develop into antisocial personality disorder when parents abuse or neglect the child or are inconsistent in discipline or in parenting style (for example, switching from being warm and supportive to being cold and critical).
Disregard for the pain of others during early childhood has been linked to antisocial behaviour during late adolescence.
Causes of Avoidant Personality Disorder
Genes and environmental factors may contribute to the development of avoidant personality disorder.
For example, people may have an inborn anxiety in social situations, and/or they may experience rejection and marginalisation during childhood.
Avoidance in social situations has been observed in children as young as about 2 years old.
Causes of Borderline Personality Disorder
Genes and environmental factors may contribute to the development of borderline personality disorder.
Certain individuals may have a genetic tendency to react poorly to life stresses, making them more likely to develop borderline personality disorder as well as other mental disorders. Also, borderline personality disorder tends to run in families, further suggesting that this tendency may be partly inherited. First-degree relatives of individuals with this disorder are 5 times more likely to have the disorder than the general population.
Stresses during early childhood may contribute to the development of borderline personality disorder. Many individuals with borderline personality disorder were physically or sexually abused, separated from caregivers, and/or lost a parent when they were children. The insecurity of their attachment to their caregivers contributes to the symptoms of borderline personality disorder.
Causes of Dependent Personality Disorder
Information about what causes dependent personality disorder is limited.
Factors that may contribute include:
- Cultural factors;
- Negative early experiences;
- An inborn tendency to be anxious; and
- Traits that run in families (such as submissiveness, insecurity, and self-effacing behaviour).
Causes of Narcissistic Personality Disorder
Genes and environmental factors may contribute to the development of narcissistic personality disorder. One theory suggests that caregivers may have interacted with the child in a way that did not help the child develop a stable sense of self. For example, caregivers may have been overly critical or praised, admired, or indulged the child too much.
Some individuals with narcissistic personality disorder have special gifts or talents and become used to associating their self-image and sense of self with the admiration and esteem of others.
Causes of Schizoid Personality Disorder
Genes are thought to play a role in the development of schizoid personality disorder. This disorder may be more common among individuals who have family members with schizophrenia or schizotypal personality disorder.
Having caregivers who were emotionally cold, neglecting, and detached during childhood may contribute to the development of schizoid personality disorder. Having such caregivers may reinforce the child’s feeling that relationships with other people are not satisfying.
Causes of Schizotypal Personality Disorder
Genes are thought to have an important role in the development of schizotypal personality disorder. It is more common among first-degree relatives (parents, siblings, and children) of people who have schizophrenia or another psychotic disorder.