This statistic has been supported by other studies in the US, with overall global prevalence statistics ranging from 9% to 11%.A UK national epidemiological study (based on DSM-IV screening criteria), reclassified into levels of severity rather than just diagnosis, reported in 2010 that the majority of people show some personality difficulties in one way or another (short of threshold for diagnosis), while the prevalence of the most complex and severe cases (including meeting criteria for multiple diagnoses in different clusters) was estimated at 1.3%. Even low levels of personality symptoms were associated with functional problems, but the most severely in need of services was a much smaller group.Personality disorders (especially Cluster A) are found more commonly among homeless people.There are some sex differences in the frequency of personality disorders which are shown in the table below. : 206  The known prevalence of some personality disorders, especially borderline PD and antisocial PD are affected by diagnostic bias. This is due to many factors including disproportionately high research towards borderline PD and antisocial PD, alongside social and gender stereotypes, and the relationship between diagnosis rates and prevalence rates. Since the removal of depressive PD, self-defeating PD, sadistic PD and passive-aggressive PD from the DSM-5, studies analysing their prevalence and demographics have been limited. History
Diagnostic and Statistical Manual history
Before the 20th century
Personality disorder is a term with a distinctly modern meaning, owing in part to its clinical usage and the institutional character of modern psychiatry.
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.