Personality disorder represents a diagnosis very different from others in psychiatry. This is because it describes a long-standing integral part of a person, not just an affliction that has happened. Because of the sensitivity of ascribing a core part of a person’s being to the impersonality of a diagnostic term, the subject has been widely stigmatised. However, the condition is very common and affects one-tenth of the population. In this chapter, the clinical features of personality disorder identified in the new ICD-11 severity classification are described and their value illustrated. A fuller description of the ICD-11 classification can be found in another College publication.

There are five levels of diagnosis of personality disorder, including the sub-syndromal form – personality difficulty – which is by far the most common. The diagnosis of borderline personality disorder is the most used in practice but is a heterogeneous term that overlaps with almost every other disorder in psychiatry. All personality disorders have approximately equal genetic and environmental precursors, and the involvement of childhood adverse experiences and trauma is unfortunately true for this as for all psychiatric disorders.

Psychiatric classification is like growing old – a subject often avoided but recognized as inevitable. Whether you use a standard classification such as ICD-11 or a personal one such as ‘people-I-feel-confident-in-treating’ or ‘people-I-prefer to avoid’, it is impossible to avoid some sort of order in a subject which can present in a myriad of ways. Carl Linnaeus, not exactly a modest man, often liked to quote his prime achievement, ‘God created the world, Linnaeus organized it’. His Systema Naturae, published in 1735, introduced the ‘definitive’ classification of all living organisms, organized into species, genera, classes, and orders. This classification certainly revolutionized biology and the Linnaean system continues to remain supreme, and in psychiatry we would like to aspire to a similar pinnacle of achievement if we were able to create a classification of equal standing. But please pause a minute. The Linnaean system is not definitive. Whole groups of organisms are now being refined by DNA technology and a new classification is likely to be on its way to replace or enhance it. All classifications are ephemeral.

Many groups are more vulnerable to violence than others, with children, some ethnic minorities and the elderly more at risk than others. In this section, these aspects of vulnerability are examined closely. Children exposed to violence are perhaps the group who suffer most, as the effects of abuse and harm can scar them for the rest of their lives. Their inability to resist makes the need for safeguarding paramount, but intervention often takes place late when the damage has been done. Older people and those with intellectual disability are similarly vulnerable and the chapters in this section offer sound advice on management. Black, Asian and other minority groups (BAME) deserve a separate chapter. They are both more vulnerable to violence and perceived as more likely to express violence, a perception that is often wrong and can have racist overtones. There is controversy over the causes of violence in this group, but the authors present a balanced view containing sound advice.

This chapter concentrates on the advice given to NHS workers in the NICE guideline of 2015 and subsequent related advice from the National Institute of Care and Clinical Excellence. In the interests of transparency, we give the principles that lie behind NICE guidance that have only recently been published. In the NICE guideline we placed great emphasis on the prevention of violence and the reduction of all forms of restrictive intervention, and the reasoning behind this is given. We point out the major impact of the environment in both facilitating prevention of violence and, sadly, all too often in over-crowded NHS settings, promoting it. Advance directives, although rarely used at present, are likely to become more relevant and need to be highlighted. Finally, we address the thorny issue of risk. In our guideline we could not give advice on sound evidence; the situation has not changed since, and the dynamic elements of a potentially violent episode are more important to attend to than even the best of written guidance.

Because violence can manifest anywhere, we all need to be prepared for its impact. The following four chapters describe the main settings outside standard psychiatric inpatient wards where violence is manifest in different ways and how the different environmental circumstances influence management.

In the community, potential victims are much less protected and, as far as is possible, de-escalation (defusion) of violence becomes the primary intervention.

The problem of violence in medical settings has sadly come to the fore in recent years because of an increase in episodes, and its management and prevention need to be developed further. Emergency departments are in the front line here, and paramedics and other ambulance staff are also vulnerable to assault. It is to be expected that when common policies of management are adopted, hospital settings will gain greatly.

The new chapter on forensic psychiatry and adult inpatient secure settings () offers readers an insight into the historical context behind the existence and development of forensic psychiatric services in England and Wales. Key pieces of legislation are outlined, as is a description of how forensic services are currently configured.

This section is concerned with the highly important subject of the interaction of violence with society as a whole. If we can improve the outcomes of children involved in violence, have good ways of linking programmes of treatment with societal understanding and can overcome the pain and anger of victims who have been exposed to violence, we will have moved a long way.

The evidence that those with mental illness are much more likely to be victims of violence than its perpetrators is repeated several times in this book, and we make no apology for this; it needs to be repeated over and over again until society understands.

Professionals working in health, social care and the justice system require a robust understanding of when to share confidential information; the information-sharing chapter (Chapter 18) has been expanded from the first edition and provides information on legislation and guidance to be considered when sharing information about patients and information sharing by organisations supporting victims of crimes committed by mentally disordered offenders. The chapter includes discussion of the new Victims’ Code and of liaison with victims.