Diagnosis and Classification of Personality Disorders
James Reich
Giovanni de Girolamo
Definitions of personality disorders
There has been considerable interest in the study of personality and personality disorder (PD) since early times and in many different cultures. However, as noted by Tyrer et al.(1) ‘The categorization of personality disorder did not receive any firm support until the time of Schneider’. Schneider(2) regarded abnormal personalities as ‘constitutional variants that are highly influenced by personal experiences’ and identified 10 specific types or classes of ‘psychopathic personality’. The classification system proposed by Schneider has deeply influenced subsequent classification systems(1): of the 10 types of PD identified by Schneider, eight are closely related to similar types of PD as classified in DSM-III.(3) Many of these categories are also represented in DSM-IV(4) and ICD-10.(5)
Personality is defined in the second edition of the WHO Lexicon of Psychiatric and Mental Health Terms(6) as ‘The ingrained patterns of thought, feeling, and behaviour characterising an individual’s unique lifestyle and mode of adaptation, and resulting from constitutional factors, development, and social experience’. Personality disorders, according to the ICD-10 diagnostic guidelines(5):
… comprise deeply ingrained and enduring behaviour patterns, manifesting themselves as inflexible responses to a broad range of personal and social situations. They represent either extreme or significant deviations from the way the average individual in a given culture perceives, thinks, feels, and particularly, relates to others. Such behaviour patterns tend to be stable and to encompass multiple domains of behaviour and psychological functioning. They are frequently, but not always, associated with various degrees of subjective distress and problems in social functioning and performance.
For example, a dependent PD in a favourable environment might not cause dysfunction, but nevertheless might be considered a disorder since it is clinically identical to the same disorder that usually causes dysfunction.
DSM-IV(4) defines a PD as ‘an enduring pattern of inner experience and behaviour that deviates markedly from the expectations of the individual’s culture’. The pattern is manifested in two or more of the following areas: cognition, affectivity, interpersonal functioning, and impulse control. The pattern is inflexible and pervasive across a broad range of situations, has an early onset, is stable and leads to significant distress or impairment.
Personality traits, according to DSM-IV,(4) ‘are enduring patterns of perceiving, relating to and thinking about the environment and oneself that are exhibited in a wide range of social and personal contexts. Only when personality traits are inflexible and maladaptive and cause significant functional impairment or subjective distress do they constitute PDs.’
ICD and DSM classifications of personality disorders
In the ICD-10 classification, which does not have a multiaxial system for the separate recording of the personality status, PD can be diagnosed together with any other mental disorder, if present. Although a multiaxial system for ICD-10 is being developed, this will not include a separate axis for PDs, as in DSM-IV.
Despite the importance given to behavioural manifestations for the classification and assessment of PDs, personality traits and attitudes are also considered when a diagnosis is made. The ICD-10 diagnostic guidelines subdivide PDs ‘according to clusters of traits that correspond to the most frequent or conspicuous behavioural manifestations’. As stressed by Widiger and Frances,(9) the reliance on behavioural indicators can improve inter-rater reliability, which reduces the amount of inferential judgement required for the diagnosis, but it does not ensure that the same diagnosis will be made at different times. Moreover, the diagnosis of a PD cannot be based on a single behaviour, as any given behaviour may have multiple causes (e.g. situational and role factors).
There have been four studies that have explored the diagnostic categories for PDs contained in ICD-10 and compared them with the DSM classification. The first(10) was carried out among 177 American clinicians who found some degree of overlap between the different categories. When the authors compared the diagnostic categories in ICD-10 with those in DSM-IIIR, they found that only anankastic (ICD) and obsessive-compulsive (DSM) PDs showed a high level of correspondence. The second study(11) looked at 52 outpatients and compared DSM-IIIR to ICD-10. It found fair concordance for the diagnosis of ‘any PD’, but poor agreement for individual PDs; the ICD-10 tended to overdiagnose PDs relative to DSM-IIIR. The third report(12) compared ICD-10 and DSM-IV in 58 patients with panic disorder. There was good agreement for the presence of ‘any PD’, and a reasonable agreement between individual diagnoses (κ ranged from 0.51 to 0.83.), with a tendency for ICD-10 to overdiagnose PDs relative to DSM-IV. In the fourth study,(13) ICD-10 criteria were found to have satisfactory interrater reliability in a sample of homeless adults.
In the American taxonomic system, a multiaxial classification was first introduced in DSM-III. With the development of DSM-IIIR, more than 100 changes in the classification of PDs were introduced compared with DSM-III.(14,15) While the multiaxial and categorical style of classification was maintained, the diagnostic criteria were revised to form a list of symptoms for each PD, of
which only a certain number were required for a diagnosis to be reached. In DSM-IIIR, each category of PD comprised 7 to 10 criteria, with the presence of four to six criteria required for diagnosis. DSM-IIIR contained 11 PDs (see Table 4.12.2.1), plus two new disorders (self-defeating PD and sadistic PD) that were not included in DSM-III but were considered as diagnostic categories needing further study. As in DSM-III, the 11 PDs were divided into three clusters:
which only a certain number were required for a diagnosis to be reached. In DSM-IIIR, each category of PD comprised 7 to 10 criteria, with the presence of four to six criteria required for diagnosis. DSM-IIIR contained 11 PDs (see Table 4.12.2.1), plus two new disorders (self-defeating PD and sadistic PD) that were not included in DSM-III but were considered as diagnostic categories needing further study. As in DSM-III, the 11 PDs were divided into three clusters:
Table 4.12.2.1 Comparison of different classification systems of personality disorders: ICD-9, ICD-10, DSM-IIIR, and DSM-IV | ||||||||||||||||||||||||||||||||||||||||||
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cluster A (the ‘odd’ or ‘eccentric’ cluster), which included paranoid, schizoid, and schizotypal PD;
cluster B (the ‘dramatic’ or ‘erratic’ cluster), which included histrionic, narcissistic, antisocial, and borderline PDs; and
cluster C (the ‘anxious’ cluster), which included avoidant, dependent, obsessive-compulsive, and passive-aggressive PDs.
One study in the United States examined changes in personality diagnoses using DSM-III versus DSM-IIIR.(16) For some categories there was a considerable difference in the frequency of diagnosis: for example, there was an 800 per cent increase in the rate of schizoid PD and a 350 per cent increase in the rate of narcissistic PD diagnosed by the clinicians when DSM-IIIR criteria were applied.
DSM-IV was designed to be a conservative evolution from DSM-IIIR; however, some differences in diagnoses between DSM-IIIR and DSM-IV can be expected.(17) In general, the different DSMs should not be considered interchangeable unless there is specific data supporting agreement of a diagnosis across systems. As shown in Table 4.12.2.1, DSM-IV includes 11 PDs as in the DSM-IIIR classification; slight changes were introduced in the diagnostic criteria, and a new category ‘PD not otherwise specified’ added. Passive-aggressive, self-defeating, and sadistic PDs (provisionally included in DSM-IIIR) were dropped. The overall effect of these changes will be to increase the concordance between the DSM-IV and the ICD-10 classification systems compared with that between DSM-IIIR and ICD-10. DSM-IV also includes the three clusters present in DSM-IIIR.
Similarities differences between ICD-10 and DSM-IV
Table 4.12.2.1 shows that for seven categories of PD (paranoid, schizoid, dissocial/antisocial, histrionic, anankastic/obsessive-compulsive, anxious/avoidant, and dependent), there is a specific correspondence between ICD-10 and DSM-IV. For three categories, there are differences in nomenclature between the two systems; in particular ICD-10 uses the term ‘anankastic’ instead of ‘obsessive-compulsive’, to avoid the erroneous implication of an inevitable link between this type of personality and obsessive-compulsive disorder. ICD-10 also uses the term ‘dissocial’ instead of ‘antisocial’, to prevent any possible connotation of stigmatization, and the term ‘anxious’ instead of ‘avoidant’. Moreover, while DSM-IV classifies borderline PD as a specific category, ICD-10 includes it as a subcategory of emotionally unstable PD. Narcissistic and passive-aggressive PDs (present in DSM-IV) are included in ICD-10 under the category of ‘other specific PDs’. Finally, while DSM-IV includes schizotypal PD as a PD, ICD-10 classifies it in the overall group of ‘Schizophrenia, schizotypal and delusional disorders’, to highlight the contiguity between this disorder and the schizophrenia group disorders, as shown by genetic and clinical studies. DSM-IV has the category ‘Personality disorders not otherwise
specified’, while ICD-10 has the category ‘Other specific personality disorders’.
specified’, while ICD-10 has the category ‘Other specific personality disorders’.
Changes in the conceptualization of DSM personality disorders since the last edition of this chapter
Empirical research has advanced in the years following the original chapter in an earlier volume. These changes have impacted our understanding and use of DSM measurement instruments. These changes are that the personality disorders as described by DSM are not as enduring as we once thought. The instruments to measure the DSM PDs have modest agreement at best on the categorical level. Finally these instruments do not seem to adequately fit most of the disorders diagnosed which are diagnosed in the remainder category, ‘Personality Disorder NOS’.
1. Research indicating lack of enduring quality of personality disorders.
There has now been considerable research indicating that some aspects of personality are state like. This was a line of research pursued by Reich(18,19) and later confirmed by others.(20) This means that some personality traits may disappear relatively rapidly—the state component. Experienced researchers have also found that even when personality disorders are selected for long-term study by careful methods, significant percentages of these will not be found on retest within a 6 month to several year periods.(21,22)
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