Transcript 6 Classification and Diagnosis

CLASSIFICATION AND DIAGNOSIS
CHRISTMAS CAROLS
• Do you hear what I hear? (schizophrenia)
• Hark! The herald angels sing about me! (narcissism)
• Jingle bells, jingle bells, jingle bells, jingle bells, jingle
bells, jingle bells, jingle bells, jingle bells (obsessivecompulsive disorder)
• Deck the halls and walls and house and street and
stores and . . . (mania)
• Santa Claus is coming to get me (paranoia)
CLASSIFICATION AND DIAGNOSIS
LECTURE OUTLINE
• Background on classification
• DSM-IV
• Reliability and validity
• Problems and objections to classification
• Epidemiological findings re: the different
disorders
CLASSIFICATION AND DIAGNOSIS
Background – Some key terms
• Classification
• Diagnosis and diagnostic system
• Assessment
• Sign vs. symptom
• Comorbidity
CLASSIFICATION AND DIAGNOSIS
Background – Functions of a good
classification system
• Organization of clinical information
• Prognosis/prediction
• Treatment possibilities/recommendations
• Heuristic
• Guidelines for financial support
CLASSIFICATION AND DIAGNOSIS
Background – History
• Greeks – melancholia, senility, alcoholism
• Kraeplin (1896) – first psychiatric
classification system
• DSM I (1952) & DSM II (1968) – very brief
manuals, guided by psychoanalysis, gross
categories (e.g., neurosis, psychosis), lack
of reliability, no research base
CLASSIFICATION AND DIAGNOSIS
Background – History
• DSM III (1980), DSM IV (1994), DSM IV TR
(2000) – field trials to improve reliability,
better research base, multiaxial
classification
CLASSIFICATION AND DIAGNOSIS
Background – The perfect system would:
• classify disorder by presenting signs and
symptoms, etiology or history, prognosis,
response to treatment
• identify different symptom clusters that
accurately signal different disorders with
no overlap between symptoms or signs
between disorders
• identity precise effective treatments
CLASSIFICATION AND DIAGNOSIS –
DSM IV
CLASSIFICATION AND DIAGNOSIS –
DSM IV
CLASSIFICATION AND DIAGNOSIS
Reliability and validity
• reliability – consistency or repeatability of
diagnoses
• inter-rater reliability – extent to which 2
clinicians agree on the diagnosis of a client
• study by Beck et al. (1962) – reliability for
DSM I categories ranged from 38% to 63%
CLASSIFICATION AND DIAGNOSIS
Reliability and validity
• study by Ward et al. (1962) of the same
data – found that most of the error in
diagnosis had to do with inconsistencies
on part of clinicians (33%) or inadequacies
of the diagnostic categories (63%), little
error attributed to inconsistencies in info
presented by clients
CLASSIFICATION AND DIAGNOSIS
Reliability and validity
• Spitzer & Fleiss (1974) – review of the
literature of reliability of DSM II – only 3
categories (mental retardation, alcoholism,
organic brain syndrome) had adequate
reliability
CLASSIFICATION AND DIAGNOSIS
Reliability and validity
• Research undertaken to improve
reliability of subsequent DSM versions
• Main finding is that reliabilities for broad
categories of Axis I is adequate, but poor
for sub-categories
CLASSIFICATION AND DIAGNOSIS
Reliability and validity
• Validity – reliability is a prerequisite for
validity
• Concurrent validity – extent to which
diagnostic category is related to nonsymptom attributes (e.g., delusions should
be related to poor occupational
functioning)
CLASSIFICATION AND DIAGNOSIS
Reliability and validity
• Predictive validity – extent to which
diagnostic category can predict future
functioning (e.g., does conduct disorder in
childhood predict antisocial behavior in
adult life)
CLASSIFICATION AND DIAGNOSIS
Problems of DSM
• Discrete categories vs. continuum –
where to do draw the line
• Gender bias – Phyllis Chesler (1972) –
women are diagnosed for overconforming
to and underconforming to sex role
stereotypes
CLASSIFICATION AND DIAGNOSIS
Problems of DSM
• Gender bias – Broverman (1970) – study
of therapists’ criteria for healthiness in
women and men – healthy woman or
unhealthy person, unhealthy woman or
healthy woman
• Gender bias – Paula Caplan (1991) –
SDPD and LLPDD
CLASSIFICATION AND DIAGNOSIS
Problems of DSM
• Cultural bias – DSM constructed
predominantly by white, US men
• Heterosexist bias – “homosexuality” was
considered a DSM disorder until 1974; it
was de-listed by a referendum of
psychiatrists!
CLASSIFICATION AND DIAGNOSIS
Broader objections to classification
• Adherence to medical model – do
psychologists want to buy into that?
• Labeling
• Stigma and discrimination
• Abuse and iatrogenic illness
CLASSIFICATION AND DIAGNOSIS
Epidemiological findings
• incidence
• prevalence
• Midtown Manhattan study (Srole et al.,
1962) – in 1954 study, 23% of adults (20-59)
had marked or severe mental illness
• 1974 follow-up of original sample, now
aged 40-79, 18% marked or severe
CLASSIFICATION AND DIAGNOSIS
Epidemiological findings
• Stirling County Nova Scotia study
(Leighton et al., 1963) – 37% of sample of
273 people judged to have symptoms
indicating mental disorder
• NIMH study in 3 US cities in early 1980s –
6-month prevalence rates of 12-13%
CLASSIFICATION AND DIAGNOSIS
Epidemiological findings – Ontario Health
Supplement study (1990s)
• 1-year prevalence rate for any disorder 30%
• lifetime prevalence rate – 48%
• most common disorders – substance
abuse, anxiety, mood disorders
CLASSIFICATION AND DIAGNOSIS
Epidemiological findings – Ontario Health
Supplement study (1990s)
• substance abuse more common among
men; anxiety, mood disorders more
common among women
• of those judged as having a disorder –
75% percent reported that they had NOT
sought help for their problems – Why?
CLASSIFICATION AND DIAGNOSIS
Epidemiological findings – Ontario Health
Supplement study (1990s)
• 81% don’t believe they have a problem
• 57% embarrassed to ask for help
• 42% uncomfortable asking for help
CLASSIFICATION AND DIAGNOSIS
Epidemiological findings – Ontario Health
Supplement study (1990s)
• 42% of those who did seek help were
judged not to have a mental health
problem!
• What does this say about the way mental
health services are organized?
SUMMARY OF CLASSIFICATION AND
DIAGNOSIS
• DSM-IV is current diagnostic system; uses
multi-axial classification and has improved
reliability over previous versions
• a number of problems and objections to use of
diagnostic systems remain
• epidemiological studies of disorders show that
these problems are widespread; a major public
health problem