Personality disorder

Personality disorders are a class of personality types and enduring behaviors associated with significant distress or disability, which appear to deviate from social expectations particularly in relating to others.^[1][2][3]

Personality disorders are included as mental disorders on Axis II of the Diagnostic manual of the American Psychiatric Association, and in the mental and behavioral disorders section of the ICD manual of the World Health Organization. Personality, defined psychologically, is the enduring behavioral and mental traits that distinguish human beings. Hence, personality disorders are defined by experiences and behaviors that differ from societal norms and expectations. Those diagnosed with a personality disorder may experience difficulties in cognition, emotiveness, interpersonal functioning or control of impulses. In general, personality disorders are diagnosed in 40-60 percent of psychiatric patients, which is the most frequent of all psychiatric diagnoses.^[4]

These behavioral patterns in personality disorders are typically associated with substantial disturbances in some behavioral tendencies of an individual, usually involving several areas of the personality, and are nearly always associated with considerable personal and social disruption. Additionally, personality disorders are inflexible and pervasive across many situations, due in large part to the fact that such behavior may be ego-syntonic (i.e. the patterns are consistent with the ego integrity of the individual) and are, therefore, perceived to be appropriate by that individual. This behavior can result in maladaptive coping skills, which may lead to personal problems that induce extreme anxiety, distress or depression.^[5] The onset of these patterns of behavior can typically be traced back to early adolescence and the beginning of adulthood and, in some instances, childhood.^[1]

Because the theory and diagnosis of personality disorders stem from prevailing cultural expectations, their validity is contested by some experts on the basis of invariable subjectivity. They argue that the theory and diagnosis of personality disorders are based strictly on social, or even sociopolitical and economic considerations.^[6][7][8][9]

Classification

The two major systems of classification, the ICD and DSM, have deliberately merged their diagnoses to some extent, but there remain differences. For example, ICD-10 does not include narcissistic personality disorder as a distinct category, while DSM-IV does not include enduring personality change after catastrophic experience or after psychiatric illness. ICD-10 classifies the DSM-IV schizotypal personality disorder as a form of schizophrenia rather than as a personality disorder. DSM-IV places personality disorders on a separate 'axis' to mental disorders, while the ICD does not use a multiaxial system. There are accepted diagnostic issues and controversies with regard to either section, in terms of distinguishing personality disorders as a category from other types of mental disorder or from general personality functioning, or distinguishing particular personality disorder categories from each other.^[10]

World Health Organization

The ICD-10 section on mental and behavioral disorders includes categories of personality disorder and enduring personality changes. They are defined as ingrained patterns indicated by inflexible and disabling responses that significantly differ from how the average person in the culture perceives, thinks and feels, particularly in relating to others.^[11]

The specific personality disorders are: Paranoid, Schizoid, Dissocial, Emotionally unstable (borderline type and impulsive type), Histrionic, Anankastic, Anxious (avoidant) and Dependent.

There is also an 'Other' category involving conditions characterized as eccentric, haltlose (drifting, aimless and irresponsible^[12]), immature, narcissistic, passive-aggressive or psychoneurotic. An additional category is for unspecified Personality disorder, including Character neurosis and pathological personality.

There is also a category for Mixed and other personality disorders, defined as conditions that are often troublesome but do not demonstrate the specific pattern of symptoms in the named disorders. Finally there is a category of Enduring personality changes, not attributable to brain damage and disease. This is for conditions that seem to arise in adults without a diagnosis of personality disorder, following catastrophic or prolonged stress or other psychiatric illness.

American Psychiatric Association

The Diagnostic and Statistical Manual of Mental Disorders (currently the DSM-IV) lists ten personality disorders, grouped into three clusters in Axis II. The DSM also contains a category for behavioral patterns that do not match these ten disorders, but nevertheless exhibit characteristics of a personality disorder. This category is labeled Personality disorder not otherwise specified.

Cluster A (odd or eccentric disorders)

• Paranoid personality disorder: characterized by irrational suspicions and mistrust of others.
• Schizoid personality disorder: lack of interest in social relationships, seeing no point in sharing time with others, anhedonia, introspection.
• Schizotypal personality disorder: characterized by odd behavior or thinking.

Cluster B (dramatic, emotional or erratic disorders)

• Antisocial personality disorder: a pervasive disregard for the law and the rights of others.
• Borderline personality disorder: extreme "black and white" thinking, instability in relationships, self-image, identity and behavior often leading to self-harm and impulsivity. Borderline personality disorder is diagnosed in three times as many females as males.^[13]
• Histrionic personality disorder: pervasive attention-seeking behavior including inappropriately seductive behavior and shallow or exaggerated emotions.
• Narcissistic personality disorder: a pervasive pattern of grandiosity, need for admiration, and a lack of empathy.

Cluster C (anxious or fearful disorders)

• Avoidant personality disorder: social inhibition, feelings of inadequacy, extreme sensitivity to negative evaluation and avoidance of social interaction.
• Dependent personality disorder: pervasive psychological dependence on other people.
• Obsessive-compulsive personality disorder (not the same as obsessive-compulsive disorder): characterized by rigid conformity to rules, moral codes and excessive orderliness.

Appendix B: Criteria Sets and Axes Provided for Further Study

Appendix B contains the following disorders.^[14]

• Depressive personality disorder – is a pervasive pattern of depressive cognitions and behaviors beginning by early adulthood.
• Passive-aggressive (negativistic) personality disorder – is a pattern of negative attitudes and passive resistance in interpersonal situations.

Other

Some types of personality disorder were in previous versions of the diagnostic manuals but have been deleted. This includes two types that were in the DSM-III-R appendix as “Proposed diagnostic categories needing further study” without specific criteria, namely Sadistic personality disorder (a pervasive pattern of cruel, demeaning and aggressive behavior) and Self-defeating personality disorder (masochistic personality disorder) (characterised by behaviour consequently undermining the person's pleasure and goals).^[15] The psychologist Theodore Millon and others consider some relegated diagnoses to be equally valid disorders, and may also propose other personality disorders or subtypes, including mixtures of aspects of different categories of the officially accepted diagnoses.^[16]

Diagnosis

The DSM-IV lists General diagnostic criteria for a personality disorder, which must be met in addition to the specific criteria for a particular named personality disorder. This requires that there be (to paraphrase):^[17]

• An enduring pattern of psychological experience and behavior that differs prominently from cultural expectations, as shown in two or more of: cognition (i.e. perceiving and interpreting the self, other people or events); affect (ie. the range, intensity, lability, and appropriateness of emotional response); interpersonal functioning; or impulse control.
• The pattern must appear inflexible and pervasive across a wide range of situations, and lead to clinically significant distress or impairment in important areas of functioning.
• The pattern must be stable and long-lasting, have started as early as at least adolescence or early adulthood.
• The pattern must not be better accounted for as a manifestation of another mental disorder, or to the direct physiological effects of a substance (e.g. drug or medication) or a general medical condition (e.g. head trauma).

The ICD-10 'clinical descriptions and diagnostic guidelines' introduces its specific personality disorder diagnoses with some general guideline criteria that are similar. To quote:^[18]

• markedly disharmonious attitudes and behaviour, involving usually several areas of functioning, e.g. affectivity, arousal, impulse control, ways of perceiving and thinking, and style of relating to others;
• the abnormal behaviour pattern is enduring, of long standing, and not limited to episodes of mental illness;
• the abnormal behaviour pattern is pervasive and clearly maladaptive to a broad range of personal and social situations;
• the above manifestations always appear during childhood or adolescence and continue into adulthood;
• the disorder leads to considerable personal distress but this may only become apparent late in its course;
• the disorder is usually, but not invariably, associated with significant problems in occupational and social performance.

The ICD adds that 'For different cultures it may be necessary to develop specific sets of criteria with regard to social norms, rules and obligations.'

In clinical practice, individuals are generally diagnosed by an interview with a psychiatrist based on a mental status examination, which may take into account observations by relatives and others. One tool of diagnosing personality disorders, is a process involving interviews with scoring systems. The patient is asked to answer questions in a questionnaire, and depending on their answers, the trained interviewer tries to code what their responses were. This process is fairly time consuming.

Normal personality and personality disorders

The issue of the relationship between normal personality and personality disorders is one of the important issues in personality and clinical psychology. The personality disorders classification (DSM IV TR and ICD-10) follow categorical approach whereas the trait personality approach follows the dimensional approach. Thomas Widiger^[19] has contributed to this debate significantly. He discussed the constraints of the categorical approach and argued for the dimensional approach to the personality disorders. The Five Factor Model of personality has been proposed as an alternative to the classification of personality disorders. Many studies across cultures have explored the relationship between personality disorders and the Five Factor Model ^[20] This talks about Five-factor translations of DSM-III-R and DSM-IV personality disorders and expounds relevance of the FFM to a variety of patient populations, including patients with borderline personality disorder, narcissism, and bulimia nervosa as well as substance abusers, psychopaths, and sex offenders.

In children and adolescents

Early stages and preliminary forms of personality disorders need a multi-dimensional and early treatment approach. Personality development disorder is considered to be a childhood risk factor or early stage of a later personality disorder in adulthood.

Causes

There are numerous possible causes of mental disorders, and they may very depending on the disorder and the individual and their circumstances. There may be genetic dispositions as well as particular life experiences, which may or may not include particular incidents of trauma or abuse.

A study of almost 600 male college students, averaging almost 30 years of age and who were not drawn from a clinical sample, examined the relationship between childhood experiences of sexual and physical abuse and currently reported personality disorder symptoms. Childhood abuse histories were found to be definitively associated with greater levels of symptomatology. Severity of abuse was found to be statistically significant, but clinically negligible, in symptomatology variance spread over Cluster A, B and C scales.^[21]

Child abuse and neglect consistently evidence themselves as antecedent risks to the development of personality disorders in adulthood.^[22] In the following study, efforts were taken to match retrospective reports of abuse with a clinical population that had demonstrated psychopathology from childhood to adulthood who were later found to have experienced abuse and neglect. In a study of 793 mothers and children, researchers asked mothers if they had screamed at their children, and told them that they didn’t love them or threatened to send them away. Children who had experienced such verbal abuse were three times as likely as other children (who didn't experience such verbal abuse) to have borderline, narcissistic, obsessive-compulsive or paranoid personality disorders in adulthood.^[23] The sexually abused group demonstrated the most consistently elevated patterns of psychopathology. Officially verified physical abuse showed an extremely strong correlation with the development of antisocial and impulsive behavior. On the other hand, cases of abuse of the neglectful type that created childhood pathology were found to be subject to partial remission in adulthood.^[22]

Prevalence

The prevalence of personality disorder in the general community was largely unknown until surveys starting from the 1990s. In 2008 the median rate of diagnosable PD was estimated at 10.6%, based on six major studies across three nations. This rate of around one in ten, especially as associated with high use of services, is described as a major public health concern requiring attention by researchers and clinicians.^[24]

A screening survey across 13 countries by the World Health Organization using DSM-IV criteria, reported in 2009 a prevalence estimate of around 6% for personality disorders.. The rate sometimes varied with demographic and socioeconomic factors, and functional impairment was partly explained by co-occurring mental disorders.^[25] In the US, screening data from the National Comorbidity Survey Replication between 2001 and 2003, combined with interviews of a subset of respondents, indicated a population prevalence of around 9% for personality disorders in total. Functional disability associated with the diagnoses appeared to be largely due to co-occurring mental disorders (Axis I in the DSM).^[26]

A UK national epidemiological study based on DSM-IV screening criteria reclassified in to 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.^[27]

Interventions

Specific approaches

There are several different forms (modalities) of treatment used for personality disorders:^[28]

• Individual psychotherapy has been a mainstay of treatment. There are long-term and short-term (brief) forms.

• Family therapy, including couples therapy.

• Group therapy for personality dysfunction is probably the second most used.

• Psychological-education may be used as an addition.

• Self-help groups may provide resources for personality disorders.

• Psychiatric medications for treating symptoms of personality dysfunction or co-occurring conditions.

• Milieu therapy, a kind of group-based residential approach, has a history of use in treating personality disorders, including therapeutic communities.

There are different specific theories or schools of therapy within many of these modalities. They may, for example, emphasize psychodynamic techniques, or cognitive or behavioral techniques. In clinical practice, many therapists use an 'electic' approach, taking elements of different schools as and when they seem to fit to an individual client. There is also often a focus on common themes that seem to be beneficial regardless of techniques, including attributes of the therapist (e.g. trustworthiness, competence, caring), processes afforded to the client (e.g. ability to express and confide difficulties and emotions), and the match between the two (e.g. aiming for mutual respect, trust and boundaries).

Challenges

The management and treatment of personality disorders can be a challenging and controversial area. By definition the difficulties have been enduring and affect multiple areas of functioning. This often involves interpersonal issues, and there can be difficulties in seeking and obtaining help from organizations in the first place, as well as with establishing and maintaining a specific therapeutic relationship. On the one hand, an individual may not consider themselves to have a mental health problem, while on the other, community mental health services may view individuals with personality disorders as too complex or difficult, and may directly or indirectly exclude individuals with such diagnoses or associated behaviors.^[29] Apart from all these issues, an individual may not consider their personality to be disordered or the cause of problems. On the one hand, this may be attributed to the person lacking insight into their own condition, and not experiencing it as being in conflict with their goals and self-image (it may therefore be termed ego-syntonic. On the other hand, it is recognised that there is not in fact a distinct or objective boundary between 'normal' and 'abnormal' personality, and in addition there is substantial social stigma and discrimination related to being diagnosed.

There is a wide range of different issues grouped under the heading of personality disorder, with different levels of severity or disability, which can require fundamentally different approaches and understandings. Some disorders or individuals are characterised by social withdrawal and shunning of relationships. There may be fluctuation between approaching and backing off. At one extreme there can be self-harm or self-neglect, while at another extreme some individuals may have committed violence and crime. There can be other factors such as problematic substance use or dependency or behavioral addictions. A person may meet criteria for multiple personality disorder diagnoses and/or other mental disorders, either at particular times or continually. This may require coordinated input from multiple services.

Therapists in this area can become disheartened by lack of initial progress, or by apparent progress that then leads to setbacks. Clients may be experienced as negative, rejecting, demanding, aggressive or manipulative. This has been looked at in terms of both therapist and client; in terms of social skills, coping efforts, defence mechanisms, or deliberate strategies; and in terms of moral judgements or the need to consider underlying motivations for specific behaviors or conflicts. The vulnerabilities of a client, and indeed therapist, may become lost behind actual or apparent strength and resilience. It is commonly stated that there is always a need to maintain appropriate professional personal boundaries, while allowing for emotional expression and therapeutic relationships. However, there can be difficulty acknowledging the different worlds and understandings that client and therapist may live with. A therapist may assume that the kinds of relationships and ways of interacting that make them feel safe and comfortable, have the same effect on clients. As an example at one extreme, people who may in their lives have been used to hostility, deceptiveness, rejection, aggression or abuse, may in some cases be made confused, intimidated or suspicious by presentations of warmth, intimacy or positivity. On the other hand, reassurance, openness and clear communication are usually helpful and needed. It can take several months of sessions, and perhaps several stops and starts, to begin to develop a trusting relationship that can meaningfully address issues.^[30]

Occupational functioning

Personality disorders can be associated with difficulty coping with work or workplaces, though it depends on the diagnosis, the severity, the individual, and the work. Similarly, problems may be caused for others in some cases. Some issues may be due to difficulties with interpersonal relationships, while others may be indirect effects, for example of impaired educational progress or lifestyle complications outside of work. There can also be higher than average work abilities in some areas, for example being more driven to out-compete others, or in some cases for some individuals to exploit co-workers. Links between personality disorders and other mental disorders, including substance use, may also account for some issues.^[31][32]

One study gave personality tests to high-level British executives as well as psychiatric and forensic psychiatric patients at Broadmoor Hospital in the UK. Using a dimensional model of personality rather than categories of diagnosis, they found that the senior business managers scored higher on traits such as superficial charm, insincerity, egocentricity and manipulative behaviors. Traits like these, if in certain combinations that are enduring and impairing, can be associated with the diagnostic category of Histrionic personality disorder. In addition, the study found that the business managers and psychiatric patients showed similar average scores on traits such as grandiosity, self-focused lack of empathy for others, exploitativeness and independence (traits sometimes associated with Narcissistic personality disorder) as well as perfectionism, excessive devotion to work, rigidity, stubbornness and dictatorial tendencies (sometimes associated with Obsessive-compulsive personality disorder). Finally they found that the business workers scored lower on some antisocial traits, such as physical aggression, irresponsibility with work or finances, not showing remorse, being impulsive, suicidal, emotional instability, mistrusting (paranoia), or hostility alternating with remorse. The study thus provided evidence that high scores on such traits are found in the general population and not just in those with syndromes (patterns) officially recognized by psychiatric diagnosis.^[33]

According to leading leadership academic Manfred F.R. Kets de Vries, narcissistic traits are exaggerations of normal self-confidence and are common in those at the top of companies, which he sometimes attributes as the cause of their rise and sometimes to factors that encourage or protect narcissism at the top. He also refers to it as a personality disorder, but identifies it in a general informal sense.^[34]

History

Personality disorder is a term with a distinctly modern meaning, owing in part to its clinical usage and the institutional character of modern psychiatry. The currently accepted meaning must be understood in the context of historical changing classification systems such as DSM-IV and its predecessors. Although highly anachronistic, and ignoring radical differences in the character of subjectivity and social relations, some have suggested similarities to other concepts going back to at least the ancient Greeks.^[3] For example, the Greek philosopher Theophrastus described 29 'character' types that he saw as deviations from the norm, and similar views have been found in Asian, Arabic and Celtic cultures. A long-standing influence in the Western world was Galen's concept of personality types which he linked to the four humours proposed by Hippocrates.

Such views lasted into the 18th century, when experiments began to question the supposed biologically-based humours and 'temperaments'. Psychological concepts of character and 'self' became widespread. In the 19th century, 'personality' referred to a person's conscious awareness of their behavior, a disorder of which could be linked to altered states such as dissociation. This sense of the term has been compared to the use of the term 'multiple personality disorder' in the first versions of the DSM.^[35]

Physicians in the early 19th century started to diagnose forms of insanity that involved disturbed emotions and behaviors but seemingly without significant intellectual impairment or delusions or hallucinations. Philippe Pinel referred to this as 'manie sans délire' - insanity without delusion - and described a number of cases mainly involving excessive or inexplicable anger or rage. James Cowles Prichard advanced a similar concept he called moral insanity, which would be used to diagnose patients for some decades. 'Moral' in this sense referred to affect (emotion or mood) rather than necessarily ethics, but it was arguably based in part on religious, social and moral beliefs, with a pessimism about medical intervention so that social control should take precedence.^[36] These categories were much different and broader than later definitions of personality disorder, while also being developed by some into a more specific meaning of moral degeneracy akin to later ideas about 'psychopaths'. Separately, Richard von Krafft-Ebing popularized the terms sadism and masochism, as well as homosexuality, as psychiatric issues.

The German psychiatrist Koch sought to make the moral insanity concept more scientific, suggesting in 1891 the phrase 'psychopathic inferiority', theorized to be a congenital disorder. This referred to continual and rigid patterns of misconduct or dysfunction in the absence of apparent mental retardation or illness, supposedly without a moral judgement. Described as deeply rooted in his Christian faith, his work has been described as a fundamental text on personality disorders that is still of use today.^[37]

20th century

In the early 20th century, another German psychiatrist Emil Kraepelin included a chapter on psychopathic inferiority in his influential work on clinical psychiatry for students and physicians. He suggested six types - excitable, unstable, eccentric, liar, swindler and quarrelsome. The categories were essentially defined by the most disordered criminal offenders observed, distinguished between criminals by impulse, professional criminals, and morbid vagabonds who wandered through life. Kraepelin also described three paranoid (meaning then delusional) disorders, resembling later concepts of schizophrenia, delusional disorder and paranoid personality disorder. A diagnostic term for the latter concept would be included in the DSM from 1952, and from 1980 the DSM would also include schizoid and schizotypal personality disorders; interpretations of earlier (1921) theories of Ernst Kretschmer led to a distinction between these and another type later included in the DSM, avoidant personality disorder.

Psychiatrist David Henderson published in 1939 a theory of 'psychopathic states' which ended up contributing to the term becoming popularly linked to anti-social behavior. Hervey M. Cleckley’s 1941 text, The Mask of Sanity, based on his personal categorization of similarities he noted in some prisoners, marked the start of the modern clinical conception of psychopathy and its popularist usage.^[38]

Towards the mid 20th century, psychoanalytic theories were coming to the fore based on work from the turn of the century being popularized by Sigmund Freud and others. This included the concept of 'character disorders', which were seen as enduring problems linked not to specific symptoms but to pervasive internal conflicts or derailments of normal childhood development. These were typically understood as weaknesses of character or willful deviance, and were distingished from neurosis or psychosis. The term 'borderline' stems from a belief that some individuals were functioning on the edge of those two categories, and a number of the other personality disorder categories were also heavily influenced by this approach, including dependent, obsessive-compulsive and histrionic,^[39] the latter starting off as a conversion symptom of hysteria particularly associated with women, then a hysterical personality, then renamed histrionic personality disorder in later versions of the DSM. A passive aggressive style was defined clinically by Colonel William Menninger during World War II in the context of men's reactions to military compliance, which would later be referenced as a personality disorder in the DSM.^[40] Otto Kernberg was influential with regard to the concepts of the borderline and narcissistic personalities which were later incorporated as disorders into the DSM in 1980.

Meanwhile, a more general personality psychology had been developing in academia and to some extent clinically. Gordon Allport was publishing theories of personality traits from the 1920s, and Henry Murray advanced a theory called 'personology' which influenced a later key advocate of personality disorders, Theodore Millon. Tests were developing or being applied for personality evaluation, including projective tests such as the Rorshach, as well as questionnaires such as the Minnesota Multiphasic Personality Inventory. Around mid-century, Hans Eysenck was analysing traits and personality types, and psychiatrist Kurt Schneider was popularising a clinical use in place of the previously more usual terms 'character', 'temperament' or 'constitution'.

American psychiatrists officially recognised concepts of enduring personality disturbances in the first Diagnostic and Statistical Manual of Mental Disorders in the 1950s, which relied heavily on psychoanalytic concepts. Somewhat more neutral language was employed in the DSM-II in 1968, though the terms and descriptions had only a slight resemblance to current definitions. The DSM-III published in 1980 made some major changes, notably putting all personality disorders onto a second separate 'axis' along with mental retardation, intended to signify more enduring patterns, distinct from what were considered axis one mental disorders. 'Inadequate' and 'asthenic' personality disorder' categories were deleted, and others were unpacked into more types, or changed from being personality disorders to regular disorders. Sociopathic Personality Disorder, which had been the term for psychopathy, was renamed Antisocial Personality Disorder. Most categories were given more specific 'operationalized' definitions, with standard criteria that psychiatrists could agree on in order to conduct research and diagnose patients.^[41] In the DSM-III revision, self-defeating personality disorder and sadistic personality disorder were included as provisional diagnoses requiring further study. They were dropped in the DSM-IV, though a proposed 'depressive personality disorder' was added; in addition, the official diagnosis of passive-aggressive personality disorder was dropped, tentatively renamed 'negativistic personality disorder.'^[42]

International differences have been noted in how attitudes have developed towards the diagnosis of personality disorder. Kurt Schneider had argued that they were simply 'abnormal varieties of psychic life' and therefore not necessarily the domain of psychiatry, a view said to still have influence in Germany today. British psychiatrists have also been reluctant to address such disorders or consider them on a par with other mental disorders, which has been attributed partly to resource pressures within the National Health Service, as well as to negative medical attitudes towards behaviors associated with personality disorders. In the US, the prevailing healthcare system and psychanalytic tradition has been said to provide a rationale for private therapists to diagnose some personality disorders more broadly and provide ongoing treatment for them.^[43]

References

Further reading

• American Psychiatric Association. (2000). Diagnostic and Statistical Manual of Mental Disorders. 4th ed. (text revision). (DSM-IV-TR). Arlington, VA.
• Häcker, H. O. Stapf (2004). Dorsch Psychologisches Wörterbuch, Verlag Hans Huber, Bern
• Marshall, W. & Serin, R. (1997) Personality Disorders. In Sm.M. Turner & R. Hersen (Eds.) Adult Psychopathology and Diagnosis. New York: Wiley. 508–541
• Murphy, N. & McVey, D. (2010) Treating Severe Personality Disorder: Creating Robust Services for Clients with Complex Mental Health Needs. London: Routledge
• Millon, Theodore (and Roger D. Davis, contributor) – Disorders of Personality: DSM IV and Beyond – 2nd ed. – New York, John Wiley and Sons, 1995 ISBN 0-471-01186-X
• Yudofsky, Stuart C. M.D. (2005) Fatal Flaws: Navigating Destructive Relationships With People With Disorders of Personality and Character, by ISBN 1-58562-214-1

External links

• Interview with Dr. Martha Stout, author of The Sociopath Next Door on the Living Hero podcast, November 2010.
• The Institute for Advanced Studies in Personology and Psychopathology the official website for Theodore Millon, Ph.D., D.Sc.
• Personality Disorders Foundation
• National Personality Disorder website for England
• Dangerous severe personality disorder
• National Mental Health Association Personality Disorder Fact Sheet
• Personality Disorders information leaflet from The Royal College of Psychiatrists