Personality disorders (PD) are a class of mental disorders characterized by enduring maladaptive patterns of behavior, cognition, and inner experience, exhibited across many contexts and deviating from those accepted by the individual's culture. These patterns develop early, are inflexible, and are associated with significant distress or disability. The definitions may vary somewhat, according to source, and remain a matter of controversy. Official criteria for diagnosing personality disorders are listed in the fifth chapter of the International Classification of Diseases (ICD) and in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM).

Personality, defined psychologically, is the set of enduring behavioral and mental traits that distinguish individual humans. Hence, personality disorders are defined by experiences and behaviors that differ from social norms and expectations. Those diagnosed with a personality disorder may experience difficulties in cognition, emotiveness, interpersonal functioning, or impulse control. In general, personality disorders are diagnosed in 40–60% of psychiatric patients, making them the most frequent of psychiatric diagnoses.

Personality disorders are characterized by an enduring collection of behavioral patterns often associated with considerable personal, social, and occupational disruption. Personality disorders are also inflexible and pervasive across many situations, largely due 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. In addition, people with personality disorders often lack insight into their condition and so refrain from seeking treatment. This behavior can result in maladaptive coping skills and may lead to personal problems that induce extreme anxiety, distress, or depression and result in impaired psychosocial functioning. These behavior patterns are typically recognized by adolescence, the beginning of adulthood or sometimes even childhood and often have a pervasive negative impact on the quality of life.

While emerging treatments, such as dialectical behavior therapy, have demonstrated efficacy in treating personality disorders, such as borderline personality disorder, personality disorders are associated with considerable stigma in popular and clinical discourse alike. 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

The two relevant 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 system is a collection of numerical codes that have been assigned to all known clinical disease states, which provides uniform terminology for medical records, billing, and research purposes. The DSM defines psychiatric diagnoses based on research and expert consensus, and its content informs the ICD-10 classifications. Both have deliberately merged their diagnoses to some extent, but some differences remain. For example, ICD-10 does not include narcissistic personality disorder as a distinct category, while DSM-5 does not include enduring personality change after catastrophic experience or after psychiatric illness. ICD-10 classifies 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.

General criteria

Both diagnostic systems provide a definition and six criteria for a general personality disorder. These criteria should be met by all personality disorder cases before a more specific diagnosis can be made.

The ICD-10 lists these general guideline criteria:

• Markedly disharmonious attitudes and behavior, generally involving several areas of functioning, e.g. affectivity, arousal, impulse control, ways of perceiving and thinking, and style of relating to others;
• The abnormal behavior pattern is enduring, of long standing, and not limited to episodes of mental illness;
• The abnormal behavior 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: "For different cultures it may be necessary to develop specific sets of criteria with regard to social norms, rules and obligations."

In DSM-5, any personality disorder diagnosis must meet the following criteria:

• An enduring pattern of inner experience and behavior that deviates markedly from the expectations of the individual's culture. This pattern is manifested in two (or more) of the following areas:
  • Cognition (i.e., ways of perceiving and interpreting self, other people, and events).
  • Affectivity (i.e., the range, intensity, lability, and appropriateness of emotional response).
  • Interpersonal functioning.
  • Impulse control.
• The enduring pattern is inflexible and pervasive across a broad range of personal and social situations.
• The enduring pattern leads to clinically significant distress or impairment in social, occupational, or other important areas of functioning.
• The pattern is stable and of long duration, and its onset can be traced back at least to adolescence or early adulthood.
• The enduring pattern is not better explained as a manifestation or consequence of another mental disorder.
• The enduring pattern is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication) or another medical condition (e.g., head trauma).

In ICD-10

Chapter V in the ICD-10 contains the mental and behavioral disorders and 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.

The specific personality disorders are: paranoid, schizoid, dissocial, emotionally unstable (borderline type and impulsive type), histrionic, anankastic, anxious (avoidant) and dependent.

Besides the ten specific PD, there are the following categories:

• Other specific personality disorders (involves PD characterized as eccentric, haltlose, immature, narcissistic, passive–aggressive, or psychoneurotic.)
• Personality disorder, unspecified (includes "character neurosis" and "pathological personality").
• 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).
• 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).

In ICD-11

In the proposed revision of ICD-11, all discrete personality disorder diagnoses will be removed and replaced by the single diagnosis "personality disorder". Instead, there will be specifiers called "prominent personality traits" and the possibility to classify degrees of severity ranging from "mild", "moderate", and "severe" based on the dysfunction in interpersonal relationships and everyday life of the patient.

In DSM-5

The most recent fifth edition of the Diagnostic and Statistical Manual of Mental Disorders stresses that a personality disorder is an enduring and inflexible pattern of long duration leading to significant distress or impairment and is not due to use of substances or another medical condition. The DSM-5 lists personality disorders in the same way as other mental disorders, rather than on a separate 'axis', as previously.

DSM-5 lists ten specific personality disorders: paranoid, schizoid, schizotypal, antisocial, borderline, histrionic, narcissistic, avoidant, dependent and obsessive-compulsive personality disorder.

The DSM-5 also contains three diagnoses for personality patterns not matching these ten disorders, but nevertheless exhibit characteristics of a personality disorder:

• Personality change due to another medical condition – personality disturbance due to the direct effects of a medical condition.
• Other specified personality disorder – general criteria for a personality disorder are met but fails to meet the criteria for a specific disorder, with the reason given.
• Unspecified personality disorder – general criteria for a personality disorder are met but the personality disorder is not included in the DSM-5 classification.

Personality clusters

The specific personality disorders are grouped into the following three clusters based on descriptive similarities:

Cluster A (odd or eccentric disorders)

Cluster A personality disorders are often associated with schizophrenia: in particular, schizotypal personality disorder shares some of its hallmark symptoms with schizophrenia, e.g., acute discomfort in close relationships, cognitive or perceptual distortions, and eccentricities of behavior. However, people diagnosed with odd-eccentric personality disorders tend to have a greater grasp on reality than those with schizophrenia. Patients suffering from these disorders can be paranoid and have difficulty being understood by others, as they often have odd or eccentric modes of speaking and an unwillingness and inability to form and maintain close relationships. Though their perceptions may be unusual, these anomalies are distinguished from delusions or hallucinations as people suffering from these would be diagnosed with other conditions. Significant evidence suggests a small proportion of people with Cluster A personality disorders, especially schizotypal personality disorder, have the potential to develop schizophrenia and other psychotic disorders. These disorders also have a higher probability of occurring among individuals whose first-degree relatives have either schizophrenia or a Cluster A personality disorder.

• Paranoid personality disorder: characterized by a pattern of irrational suspicion and mistrust of others, interpreting motivations as malevolent.
• Schizoid personality disorder: lack of interest and detachment from social relationships, apathy, and restricted emotional expression.
• Schizotypal personality disorder: pattern of extreme discomfort interacting socially, and distorted cognition and perceptions.

Cluster B (dramatic, emotional or erratic disorders)

• Antisocial personality disorder: pervasive pattern of disregard for and violation of the rights of others, lack of empathy, bloated self-image, manipulative and impulsive behavior.
• Borderline personality disorder: pervasive pattern of abrupt mood swings, instability in relationships, self-image, identity, behavior and affect, often leading to self-harm and impulsivity.
• Histrionic personality disorder: pervasive pattern of attention-seeking behavior and excessive emotions.
• Narcissistic personality disorder: pervasive pattern of grandiosity, need for admiration, and a perceived or real lack of empathy. In a more severe expression, narcissistic personality disorder may show evidence of paranoia, aggression, psychopathy, and sadistic personality disorder, which is known as malignant narcissism.

Cluster C (anxious or fearful disorders)

• Avoidant personality disorder: pervasive feelings of social inhibition and inadequacy, extreme sensitivity to negative evaluation.
• Dependent personality disorder: pervasive psychological need to be cared for by other people.
• Obsessive-compulsive personality disorder: characterized by rigid conformity to rules, perfectionism, and control to the point of satisfaction and exclusion of leisurely activities and friendships (distinct from obsessive-compulsive disorder).

Other personality types

Some types of personality disorder were in previous versions of the diagnostic manuals but have been deleted. Examples include sadistic personality disorder (pervasive pattern of cruel, demeaning, and aggressive behavior) and self-defeating personality disorder or masochistic personality disorder (characterized by behavior consequently undermining the person's pleasure and goals). They were listed in the DSM-III-R appendix as "Proposed diagnostic categories needing further study" without specific criteria. 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.

Millon's description

Psychologist Theodore Millon, who has written numerous popular works on personality, proposed the following description of personality disorders:

Additional factors

In addition to classifying by category and cluster, it is possible to classify personality disorders using additional factors such as severity, impact on social functioning, and attribution.

Severity

This involves both the notion of personality difficulty as a measure of subthreshold scores for personality disorder using standard interviews and the evidence that those with the most severe personality disorders demonstrate a “ripple effect” of personality disturbance across the whole range of mental disorders. In addition to subthreshold (personality difficulty) and single cluster (simple personality disorder), this also derives complex or diffuse personality disorder (two or more clusters of personality disorder present) and can also derive severe personality disorder for those of greatest risk.

There are several advantages to classifying personality disorder by severity:

• It not only allows for but also takes advantage of the tendency for personality disorders to be comorbid with each other.
• It represents the influence of personality disorder on clinical outcome more satisfactorily than the simple dichotomous system of no personality disorder versus personality disorder.
• This system accommodates the new diagnosis of severe personality disorder, particularly "dangerous and severe personality disorder" (DSPD).

Effect on social functioning

Social function is affected by many other aspects of mental functioning apart from that of personality. However, whenever there is persistently impaired social functioning in conditions in which it would normally not be expected, the evidence suggests that this is more likely to be created by personality abnormality than by other clinical variables. The Personality Assessment Schedule gives social function priority in creating a hierarchy in which the personality disorder creating the greater social dysfunction is given primacy over others in a subsequent description of personality disorder.

Attribution

Many who have a personality disorder do not recognize any abnormality and defend valiantly their continued occupancy of their personality role. This group have been termed the Type R, or treatment-resisting personality disorders, as opposed to the Type S or treatment-seeking ones, who are keen on altering their personality disorders and sometimes clamor for treatment. The classification of 68 personality disordered patients on the caseload of an assertive community team using a simple scale showed a 3 to 1 ratio between Type R and Type S personality disorders with Cluster C personality disorders being significantly more likely to be Type S, and paranoid and schizoid (Cluster A) personality disorders significantly more likely to be Type R than others.

Presentation

Comorbidity

There is a considerable personality disorder diagnostic co-occurrence. Patients who meet the DSM-IV-TR diagnostic criteria for one personality disorder are likely to meet the diagnostic criteria for another. Diagnostic categories provide clear, vivid descriptions of discrete personality types but the personality structure of actual patients might be more accurately described by a constellation of maladaptive personality traits.

Sites used DSM-III-R criterion sets. Data obtained for purposes of informing the development of the DSM-IV-TR personality disorder diagnostic criteria.

Abbreviations used: PPD – Paranoid Personality Disorder, SzPD – Schizoid Personality Disorder, StPD – Schizotypal Personality Disorder, ASPD – Antisocial Personality Disorder, BPD – Borderline Personality Disorder, HPD – Histrionic Personality Disorder, NPD – Narcissistic Personality Disorder, AvPD – Avoidant Personality Disorder, DPD – Dependent Personality Disorder, OCPD – Obsessive-Compulsive Personality Disorder, PAPD – Passive-Aggressive Personality Disorder.

Impact on functioning

It is generally assumed that all personality disorders are linked to impaired functioning and a reduced quality of life (QoL) because that is a basic diagnostic requirement. But research shows that this may be true only for some types of personality disorder.

In several studies, higher disability and lower QoL were predicted by avoidant, dependent, schizoid, paranoid, schizotypal and antisocial personality disorder. This link is particularly strong for avoidant, schizotypal and borderline PD. However, obsessive-compulsive PD was not related to a compromised QoL or dysfunction. A prospective study reported that all PD were associated with significant impairment 15 years later, except for obsessive compulsive and narcissistic personality disorder.

One study investigated some aspects of "life success" (status, wealth and successful intimate relationships). It showed somewhat poor functioning for schizotypal, antisocial, borderline and dependent PD, schizoid PD had the lowest scores regarding these variables. Paranoid, histrionic and avoidant PD were average. Narcissistic and obsessive-compulsive PD, however, had high functioning and appeared to contribute rather positively to these aspects of life success.

There is also a direct relationship between the number of diagnostic criteria and quality of life. For each additional personality disorder criterion that a person meets there is an even reduction in quality of life.

Issues

In the workplace

Depending on the diagnosis, severity and individual, and the job itself, personality disorders can be associated with difficulty coping with work or the workplace—potentially leading to problems with others by interfering with interpersonal relationships. Indirect effects also play a role; for example, impaired educational progress or complications outside of work, such as substance abuse and co-morbid mental disorders, can plague sufferers. However, personality disorders can also bring about above-average work abilities by increasing competitive drive or causing the sufferer to exploit his or her co-workers.

In 2005 and again in 2009, psychologists Belinda Board and Katarina Fritzon at the University of Surrey, UK, interviewed and gave personality tests to high-level British executives and compared their profiles with those of criminal psychiatric patients at Broadmoor Hospital in the UK. They found that three out of eleven personality disorders were actually more common in executives than in the disturbed criminals:

• Histrionic personality disorder: including superficial charm, insincerity, egocentricity and manipulation
• Narcissistic personality disorder: including grandiosity, self-focused lack of empathy for others, exploitativeness and independence.
• Obsessive-compulsive personality disorder: including perfectionism, excessive devotion to work, rigidity, stubbornness and dictatorial tendencies.

According to leadership academic Manfred F.R. Kets de Vries, it seems almost inevitable that some personality disorders will be present in a senior management team.

In children

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. In addition, in Robert F. Krueger's review of their research indicates that some children and adolescents do suffer from clinically significant syndromes that resemble adult personality disorders, and that these syndromes have meaningful correlates and are consequential. Much of this research has been framed by the adult personality disorder constructs from Axis II of the Diagnostic and Statistical Manual. Hence, they are less likely to encounter the first risk they described at the outset of their review: clinicians and researchers are not simply avoiding use of the PD construct in youth. However, they may encounter the second risk they described: under-appreciation of the developmental context in which these syndromes occur. That is, although PD constructs show continuity over time, they are probabilistic predictors; not all youths who exhibit PD symptomatology become adult PD cases.

Versus mental disorders

The disorders in each of the three clusters may share with each other underlying common vulnerability factors involving cognition, affect and impulse control, and behavioral maintenance or inhibition, respectively. But they may also have a spectrum relationship to certain syndromal mental disorders:

• Paranoid, schizoid or schizotypal personality disorders may be observed to be premorbid antecedents of delusional disorders or schizophrenia.
• Borderline personality disorder is seen in association with mood and anxiety disorders, with impulse control disorders, eating disorders, ADHD, or a substance use disorder.
• Avoidant personality disorder is seen with social anxiety disorder.

Versus normal personality

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-5 and ICD-10) follows a categorical approach that views personality disorders as discrete entities that are distinct from each other and from normal personality. In contrast, the dimensional approach is an alternative approach that personality disorders represent maladaptive extensions of the same traits that describe normal personality.

Thomas Widiger and his collaborators have contributed to this debate significantly. He discussed the constraints of the categorical approach and argued for the dimensional approach to the personality disorders. Specifically, he proposed the Five Factor Model of personality as an alternative to the classification of personality disorders. For example, this view specifies that Borderline Personality Disorder can be understood as a combination of emotional lability (i.e., high neuroticism), impulsivity (i.e., low conscientiousness), and hostility (i.e., low agreeableness). Many studies across cultures have explored the relationship between personality disorders and the Five Factor Model. This research has demonstrated that personality disorders largely correlate in expected ways with measures of the Five Factor Model and has set the stage for including the Five Factor Model within DSM-5.

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, and depending on their answers, the trained interviewer tries to code what their responses were. This process is fairly time-consuming.