When the ICD-11 working group for the revision of the classification of personality disorders was established in 2010, there was both an increasing concern, followed by general consensus, that the existing classification in ICD-10 and DSM-IV were no longer fit for purpose. First, the system was complex, with around 80 criteria and 10 separate categories. These categories had evolved from historical precedents, clinical experience, and committee consensus. There was no coherent model or theory for the diagnoses. Some categories had their origins in Galen’s temperaments described over 1800 years ago (Galen, 192), while others, such as borderline personality disorder, had appeared very recently. Clinicians responded to this confusion by often ignoring the whole concept of personality disorders, resulting in low rates of diagnosis in clinical practice. Rates of clinical diagnoses are generally reported to be less than one-quarter of those in systematic prevalence studies.1 When clinicians did make a personality disorder diagnosis, they usually confined themselves to 2 of the 10 categories; borderline personality disorder or antisocial personality disorder, or used the catch-all ‘personality disorder not otherwise specified’ (PD-NOS), or mixed and other personality disorders (61.0) in ICD-10.

There is a natural curiosity about why some people are healthier than others. One consistent theme is that dispositional variables or personality may predispose people to poor or good health. This idea can be traced back to the writings of ancient scholars such as Hippocrates and Galen who proposed that individual differences in the four humours could predict health outcomes. Galen, for example, warned that melancholic women compared with sanguine women had a higher risk for breast cancer (Van Heck, 1997).

This chapter addresses one of the most serious matters in the study of personality disorder that is in danger of permanently handicapping understanding and treatment. It could, in the end, sabotage research and keep the subject as an esoteric one where only a small number of zealots communicate amongst themselves. It is a concern that the two highly respected handbooks recently published on personality disorder (Livesley and Larstone, 2018; Lejuez and Gratz, 2020) have no chapters or discussion sections on the stigma of personality disorders, despite its importance.

Historical chapters in scientific books are generally dull even though they do not intend to be. There is an understandable need to record what happened in the past even though it may be quite irrelevant to what is going on today. We are frequently asked to remember George Santayana’s comment, made by many others, that ‘those who cannot remember the past are condemned to repeat it’ (Santayana, 1905). But this is hardly relevant for a textbook on The Wheel. Those who concentrate on wheel technology are not going to be particularly interested, except in a voyeuristic sense, in how Neolithic people might have been able to move large blocks of stone to Stonehenge for hundreds of miles using primitive garden rollers. But with personality disorder it is different. Without some knowledge of the history of personality disorder current descriptions cannot be placed in any sort of context.

As we have already noted from the history of personality disorder, when very little was known apart from the humoral theory of disease, it was common to think of temperament (aka personality) as the main progenitor of illness, with all other psychological symptoms considered as secondary epiphenomena. For example, Robert Burton described dozens of symptoms linked to the melancholic temperament, rather too many in his view: ‘The tower of Babel never yielded such confusion of tongues as the chaos of melancholy doth variety of symptoms,’ (Burton, 1621; republished 1927).

The term ‘personality difficulty’ will be unfamiliar to most people except as a general concept, but it will be part of the ICD-11 diagnostic spectrum of personality disorder in January 2022. We know a fair deal about it, but it is not a diagnosis. It is listed in the section of the ICD-11 classification for ‘non-disease entities that constitute factors, influencing health status and encounters with health services, that may be of clinical importance’, called Q Factors. The important section for personality difficulty is QE50 (problems associated with relationships). The full QE50 list is shown in Table 3.1.