Abnormal Psychology

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The Nature of Psychopathology and Abnormal Psychology
The Diagnosis of Mental Disorders

Personality Disorder Not Otherwise Specified (PDNOS)

PDNOS was first introduced in the DSM-III in 1980. It is one of the most frequently used personality disorder diagnoses. One can meet diagnostic criteria in a number of ways, such as:

  • having a PD that is not among the officially recognized diagnostic categories
  • having features of more than one of the officially recognized diagnostic categories that do not meet the full criteria of any one PD but that together cause clinically significant distress or functional impairment
  • having a clinically significant, although sub-threshold, variant of a specific diagnostic category

This category can also be used when the clinician judges that a specific Personality Disorder that is not included in the Classification is appropriate. Examples include:

  • depressive personality disorder
  • passive-aggressive personality disorder.

Guidelines for PDNOS are relatively unspecified and difficult to follow when assessing PDs. There are no explicit algorithms provided for mixed, atypical, and other PDs. Only slightly more than half studies provide an operational definition of PDNOS. The most frequently occurring definition is "mixed" PD

There are different Axis II instruments that provide different guidelines for diagnosing PDNOS, such as:

  • Structured Interview for DSM-IV Personality (SIDP-IV)

    • recommends using PDNOS only when two or more disorders are just one criterion short of diagnostic threshold

  • International Personality Disorder Examination (IPDE)

    • requires the presence of at least 10 diagnostic criteria of different specific PDs in order for PDNOS to be diagnosed

  • Personality Disorder Interview-IV (PDI-IV)

    • requires that the respondent meet the general diagnostic criteria for a PD

(Verheul & Widiger, 2004)


  • Less than half of all studies providing overall Axis II prevalences provide a separate rate for PDNOS

    • Studies that do not take PDNOS into account may be grossly understimating the prevalance and/or failing to consider adequately the extent to which personality pathology has impacted the results

  • The best estimate of the absolute prevalence of PDNOS in patient samples is in the range of 8 to 13%
  • The best estimate of the relative prevalence of PDNOS is in the range of 21 to 49%
  • In structured interview studies, PDNOS is the third most frequently used PD diagnosis, whereas in non-structured interview studies, PDNOS is often the single most frequently used diagnosis
  • PDE/IPDE yielded higher PDNOS prevalences than either the SCID or SIDP

(Verheul & Widiger, 2004)

Associated Features

  • The only required sign and symptom is that a person's social or mental personality be effected or impaired in such a way that it causes a distress or dysfunction in one or more of the important areas of life.
  • Symptoms are a large mixed list of any personality linked dysfunction, sign, symptom, or complaint that will not fit into a specific disorder category.
  • The important areas of life are:

    • social
    • occupational
    • sexual
    • interpersonal

  • Those that meet the criteria for Personality Disorder Not Otherwise Specified have a higher risk of behavioral, educational, and interpersonal problems during childhood and early adulthood than those with a specified personalty disorder.
  • They also have an increased risk of having later education failures, interpersonal relationship difficulties, psychiatric disorders and serious physical aggression acts by the time that they are adults.

DSM-V Changes

  • Personality Disorder Not Otherwise Specified will not be included in DSM-5. This disorder should be represented and diagnosed by a combination of core impairments in personality functioning and patients' unique pathological personality traits.
  • Prominent Personality Traits: Unique to each individual

(APA, 2010)

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