Diagnostic systems, validity, and reliability

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Diagnostic systems, validity, and reliability

• Taxonomy and category

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What do taxonomies do?

• Linnaeus taxonomy
• The periodic table
• Is order uncovered
• or constructed?

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One approach to categorizing

• An ancient Chinese encyclopedia supposedly
  divided up the animal world into the following
  categories

• (a) those that belong to the emperor
• (b) embalmed ones
• (c) those that are trained
• (d) suckling pigs
• (e) mermaids
• (f) fabulous ones
• (g) stray dogs
• (h) those that are included in
• this classification

• those that tremble as if
• they were mad
• (j) innumerable ones
• (k) those drawn with a very fine
• camels-hair brush
• (l) Others
• (m) those that have just broken
• a flower vase
• (n) those that resemble flies
• from a distance.

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Historical nosologies

• Hippocrates
• Griesinger and Kraepelin
• 1882 Statistical Committee report
• 1886 Association of Medical Superintendents
• 1893 The Bertillon classification ? ICD
• ICD-5 (1939)
• ICD-6 (1948) Section V and the WHO
• Factors influencing health status

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The DSM (Diagnostic and Statistical Manual)

• 1952 DSM (I) differed from ICD
• 1968 DSM-II and ICD-8
• 1980 DSM-III and ICD-9 CM
• 1987 DSM-III-R
• 1994 DSM-IV
• 2000 DSM-IV-TR
• 2002 Research agenda for DSM-V
• 2011 Estimated publication date for DSM-V
• See http//www.dsm5.org/, an APA website, for
  more details.

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The multiaxial system

• The concept of axial diagnosis
• The five axes
• I. Clinical Disorders/Other conditions (V codes)
• II. Personality disorders and Mental Retardation
• eg. Antisocial Personality Disorder
• Borderline Personality Disorder
• Schizoid Personality Disorder
• III. General Medical Conditions
• IV.Psychosocial/Environmental problems
• V. Global Assessment of Functioning

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A sample diagnosis

• Janie, 24, is frequently depressed, for two or
  three weeks at a time, and she often thinks of
  ending it all as a way out of her problems. Even
  when she is not depressed, she cannot seem to
  maintain a relationship. Whenever she dates a
  new man, although he seems nice at first, she
  soon discovers that he has been using her, and
  she breaks it off, usually in a screaming tirade.

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More on Janie

• She is in good health, generally, although she
  has asthma that developed at age 14. She is
  currently unemployed, having lost her third job
  since college six months ago. She lives alone,
  as her roommate asked her to leave when she could
  not keep up with her share of the rent.
• She tells you that the five psychologists she has
  seen in the past six months give her a GAF score
  of 70, and you find the same result.

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DSM-IV diagnosis

• Axis I Major Depression
• Unemployment (V code)
• Axis II Borderline Personality Disorder
• Axis III Asthma
• Axis IV Work problem
• Housing problem
• Relationship problem
• Axis V GAF score of 70

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A real case

• Dr.Young
• Schizophrenic since age 25 1993. First referral
  to psychiatry age thirteen 1981.
• Am now 37 years old.
• Date of birth August 31st, 1967.
• Released from Psych ward September 11th, 2004.
  Ninth hospitalization since 1992.
• Symptoms
• Believes mind is opened, telepathic, apocalyptic
  religiousities, lack of concentration,

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More case report

• Patient has striking sense of humor and was
  obsessional neurotic child, disliked by peers.
• Patient has steadfast belief in Matthew 24 as
  literal/normative to reader and The Book of
  Revelation since 1992.
• Political orientation towards cultural heritage
  inappropracy/i.e. is non-"Christian German
  Democrat" although of German ancestry.
• Resembles insanity as patient.
• Would be good to look into

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Is classification value-neutral?

• Categorization loses information
• Eg. Are you happy? Vs. How happy are you?
• But is the lost information relevant?
• Is the category trivial?
• Categorization produces social stigma
• It may increase demand characteristics
• It may affect the diagnostician (Rosenhan, 1973)
• It may have little practical effect
• Categorization tempts us to nominal explanation

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Advantages of classification

• Facilitates symptom-focussed treatment
• Emphasizes individual differences PKU, Bipolar
  Disorder
• Clarifies research The DSM-III boom
• Comforts and encourages patients

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Categorical classification in DSM-IV

• Category vs. continuum/dimension
• Reliabilityat the price of arbitrariness
• Interrater and internal consistency (inter-item)
• Test-retest and alternate form
• Validity
• Etiological
• Content (descriptive)
• Criterion (concurrent)
• Predictive
• Construct

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Possible changes for DSM-V

• A personal health index, for positive psychology
  indicators
• Recognize categories for overlap
• A dimensional approach
• Organization by causes rather than symptoms
• Define disability separately from symptoms

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Cultural formulation in DSM-IV

• Cultural identity
• For migrants and minorities, note identification
  with culture of origin and host culture
• Cultural explanations of illness
• Cultural environment factors
• Cultural aspects to clinical relationship
• Cultural attitudes toward diagnosis

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Examples of Culture-Bound Syndromes

• Amok
• Ataque de nervios
• Hwa-byung or Wool-hwa-byung
• Latah
• Pibloktoq
• Zar

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Some Axis I Clinical Syndromes

• Substance-related disorders
• Schizophrenia
• Mood disorders
• Anxiety disorders
• Somatoform disorders
• Dissociative disorders
• Eating disorders

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The GAF scale

• 91-100 Superior symptom-free
• 81-90 Generally good minimal or no symptoms
  everyday problems only
• 71-80 OK transient, understandable symptoms
  slight impairment
• 61-70 Mild problems mild symptoms and some
  difficulty functioning in 1 area
• 51-60 Moderate problems 1 area
• 41-50 Serious problems 1 area

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The GAF scale, continued

• 31-40 Serious thought/communication problems
  problems in multiple areas
• 21-30 Psychotic symptoms
• 11-20 Dangerous symptoms
• 1-10 Persistent danger to self or others
• 0 Inadequate information