Rigidity is the most obvious aspect of (low) openness among personality disorders and that shows lack of knowledge of ones emotional experiences. It is most characteristic of obsessive–compulsive personality disorder; the opposite of it known as impulsivity (here: an aspect of openness that shows a tendency to behave unusually or autistically) is characteristic of schizotypal and borderline personality disorders. Causes
Currently, there are no definitive proven causes for personality disorders. However, there are numerous possible causes and known risk factors supported by scientific research that vary depending on the disorder, the individual, and the circumstance. Overall, findings show that genetic disposition and life experiences, such as trauma and abuse, play a key role in the development of personality disorders. Child abuse
Child abuse and neglect consistently show up as risk factors to the development of personality disorders in adulthood. A study looked at retrospective reports of abuse of participants that had demonstrated psychopathology throughout their life and were later found to have past experience with abuse. In a study of 793 mothers and children, researchers asked mothers if they had screamed at their children, and told them that they did not love them or threatened to send them away. Children who had experienced such verbal abuse were three times as likely as other children (who did not experience such verbal abuse) to have borderline, narcissistic, obsessive–compulsive or paranoid personality disorders in adulthood. The sexually abused group demonstrated the most consistently elevated patterns of psychopathology.
Despite various methodological schemas designed to categorize personality disorders, many issues occur with classifying a personality disorder because the theory and diagnosis of such disorders occur within prevailing cultural expectations; thus, their validity is contested by some experts on the basis of inevitable subjectivity. They argue that the theory and diagnosis of personality disorders are based strictly on social, or even sociopolitical and economic considerations. Classification and symptoms
The two latest editions of the major systems of classification are

the International Classification of Diseases (11th revision, ICD-11) published by the World Health Organization
the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition, DSM-5) by the American Psychiatric Association.The ICD is a collection of alpha-numerical codes which have been assigned to all known clinical states, and provides uniform terminology for medical records, billing, statistics and research. The DSM defines psychiatric diagnoses based on research and expert consensus. Both have deliberately aligned their diagnoses to some extent, but some differences remain. For example, the ICD-10 included narcissistic personality disorder in the group of other specific personality disorders, while DSM-5 does not include enduring personality change after catastrophic experience. The ICD-10 classified the DSM-5 schizotypal personality disorder as a form of schizophrenia rather than as a personality disorder. There are accepted diagnostic issues and controversies with regard to distinguishing particular personality disorder categories from each other. Dissociative identity disorder, previously known as multiple personality as well as multiple personality disorder, has always been classified as a dissociative disorder and never was regarded as a personality disorder.