Classification in Psychiatry The concept, reliability, validity, advantages and disadvantages of different classification systems, controversies in psychiatry classification

1. CLASSIFICATION IN
PSYCHIATRY
CONCEPT, RELIABILITY, VALIDITY,
ADVANTAGES, DISADVANTAGES,
CONTROVERSIES
Dr AMIT CHOUGULE

2. OVERVIEW
 CLASSIFICATION IN PSYCHIATRY
 ADVANTAGES
 DISADVANTAGES
 APPROACHES TO CLASSIFICATION
 RELIABILITY
 VALIDITY
 CONTROVERSIES

3. CLASSIFICATION

4. INTRODUCTION
 There is a natural human predilection to categorize
and classify
 To simplify and organize the wide range of observable
phenomena and experiences
 Facilitates understanding and their predictability

5. CLASSIFICATION
 Classification is a process by which complex phenomena
are reduced by rearranging into categories based on
shared characteristics (K. S. Jacob, IJP, 2010)
 Classification in science involves forming categories or
taxa for ordering natural objects or entities and
assigning names to these categories

6. PRINCIPAL FUNCTIONS OF MEDICAL
CLASSIFICATIONS
1. Denomination:
 Assigning a common name to a group of phenomena
2. Qualification:
 Enriching the information content of a category by
adding relevant descriptive features
3. Prediction:
 A statement about the expected course and outcome,
as well as the likely response to treatment

7. UNITS OF CLASSIFICATIONS
 Disease:
 A disease is a particular abnormal condition, a disorder of
a structure or function, that affects part or all of an
organism
 A medical condition associated with specific symptoms
and signs
 Disorder:
 Breach of order; disorderly conduct; public disturbance
 A disturbance in physical or mental health or functions
malady or dysfunction
 Syndrome:
 A group of symptoms which consistently occur together
or a condition characterized by a set of associated
symptoms

8. CLASSIFICATION IN PSYCHIATRY
 Classification in Psychiatry is different as compared to
other biological classifications
 The objects classified in psychiatry are not “natural”
entities but “man made” explanatory constructs
 DSM-5 and ICD-10 are not systematic classifications in
the sense in which that term is applied in biology

9. CLASSIFICATION IN PSYCHIATRY
 Social anthropologists claim that current psychiatric
classifications are analogous to indigenous or “folk”
classifications of animals or plants
 They do not consist of mutually exclusive categories,
have no hierarchies but have some rules
 They are pragmatic and adapted to the needs of
everyday life

10. DISORDER AS A UNIT OF PSYCHIATRIC
CLASSIFICATION
 The generic term “Disorder” first introduced as a
unit of psychiatric classification in DSM-I in 1952
 Disorder has no correspondence with concept of
disease or syndrome in medical classifications

11. ADVANTAGES OF CLASSIFICATION IN
PSYCHIATRY
 To allow mental health practitioners and researchers
to communicate more effectively with each other
 “Patient has major depressive disorder”
1. Conveys a great deal of information in few words
2. Mood is a central aspect of the presenting problem
3. It is not the kind of “normal” mood fluctuation
4. what is not to be found in this patient

12. ADVANTAGES OF CLASSIFICATION IN
PSYCHIATRY
 To arrive at a diagnosis that has important
predictive power
 Diagnosis of Bipolar disorder
1. Choice of treatment options
2. Certain course may be likely
3. Increased prevalence in family member

13. ADVANTAGES OF CLASSIFICATION IN
PSYCHIATRY
 Education of current and future practitioners
 Organization of disorders into diagnostic classes
 Structure for teaching phenomenology and differential
diagnosis
 Psychoeducation of patients and their families

14. ADVANTAGES OF CLASSIFICATION IN
PSYCHIATRY
 To demonstrate to patients that their patterns of
symptoms are not mysterious and unique but identified
and studied in others
 To make decisions about insurance coverage
 Attorneys in malpractice suits and in other litigation
 Health care epidemiologists to determine the incidence
and prevalence of disorders

15. APPROACHES TO CLASSIFICATION
1. Etiological Versus Descriptive
2. Syndrome Versus Symptom
3. Categorical Versus Dimensional

16. ETIOLOGICAL VERSUS DESCRIPTIVE
 Two fundamental approaches:
1. Etiological
2. Descriptive
(First, 1994)
 Etiology-based classification systems are organized
around presumed pathogenetic processes
 Relatively few diagnostic entities
 Relatively easy to use
 Very few etiological factors have been elucidated

17. ETIOLOGICAL APPROACH
 16th century Swiss physician Paracelsus developed a
classification system
 He divided psychotic presentations into three types of
disorders based on presumed etiology
 VESANIA: Disorders caused by poisons
Substance-induced disorders
 INSANITY: Diseases caused by heredity
Schizophrenia and bipolar disorder
 LUNACY: Periodical condition
Influenced by the phases of Moon
Has no analogous condition today

18. ETIOLOGICAL APPROACH
 Etiological basis for most psychiatric conditions
remains unknown
 Based on a particular theories about the causes of
mental disorders
 Very useful to proponents of that particular theory
 Less useful for proponents of other etiological
theories

19. DESCRIPTIVE APPROACH
 Descriptive approach to classification defines
disorders based on clinical descriptions of presenting
symptoms
 It has proved to be of greater utility
 This approach advanced by the work of the nineteenth
century psychiatrist Emil Kraepelin (Kraepelin, 1992)
 Forms the basis for the current DSM and ICD
classification system

20. SYNDROME VERSUS SYMPTOM
 DSM/ICD lacks a specific etiological conceptualization
 What is organizing principle of DSM/ICD?
 The fundamental diagnostic element of the DSM/ICD is
the syndrome
 Syndrome is a group or pattern of symptoms that
appear together temporally in many individuals
 These symptoms cluster together in clinically meaningful
way
 They may reflect a common etiological process, course,
or treatment response

21. INDIVIDUAL SYMPTOM CLASSIFICATION
 Psychiatric presentation could be classified by
enumerating all relevant symptoms
 Historically there have been such symptom-based
classifications
 Boissier de Sauvages in 18th century proposed a medical
classification system
 He arranged presenting symptoms into numerous
classes, orders, and genera, comparable to the
classification of plants and animals
 This approach generated 2400 disorders each of which
was essentially a symptom
(Boissier de Sauvages, 2012)

22. CATEGORICAL VERSUS DIMENSIONAL
 Disorders included in DSM/ICD are defined
categorically
 Diagnostic criteria are provided for each disorder
 They indicate if a clinical presentation either meets or
does not meet the definitional requirements for a
particular disorder
 This method of classification is similar to one used in
the rest of medicine
 Patient either has or does not have pneumonia

23. CATEGORICAL VERSUS DIMENSIONAL
 This tendency to define illnesses in terms of
categories reflects basic human thought processes
 Use of nouns in everyday speech to indicate
categories of “things”
(e.g., chairs, tables, dogs, cats)

24. DIMENSIONAL CLASSIFICATION
 Variation in symptomatology can be represented by a
set of dimensions
 Blood pressure which is measured along a continuum
from low to high
 It only becomes a categorical construct when we apply
the label “hypertension” to indicate that a patient has a
significant elevation in blood pressure above a defined
cut-point

25. DISADVANTAGES OF CATEGORICAL SYSTEM
 Basic assumption is that Mental disorders are:
1. Discrete entities
2. Separated from one another and from normality
3. By recognizably distinct combinations of symptoms
or by demonstrably distinct etiologies
 True only for a small number of conditions
 Downs syndrome, fragile X syndrome, Alzheimer’s
disease, Huntington’s disease
 Little evidence supporting the applicability of this model
for other psychiatric disorders

26. DISADVANTAGES OF CATEGORICAL
SYSTEM
 Validity of the categorical approach has been
increasingly questioned
 Categorical disorders such as major depressive
disorder, anxiety disorders, schizophrenia and
bipolar disorder seem to merge imperceptibly both
into one another and into normality with no
demonstrable natural boundaries
(Goldberg, 1996; Widiger & Samuel, 2005)

27. DISADVANTAGES OF CATEGORICAL
SYSTEM
 The introduction to the DSM-IV-TR makes it clear
that
 “Although a categorical classification is described in
the manual this should not be interpreted as
suggesting that the categorical approach is more
reliable or valid than a dimensional approach toward
classification”

28. ADVANTAGES OF DIMENSIONAL APPROACH
 Commonly observed phenomena:
1. Excessive comorbidity
2. An individual receiving multiple simultaneous DSM
diagnoses
 Direct result of having a categorical system with more
than 250 narrowly defined discrete categories
 Dimensional approach indicates the extent of psychiatric
symptomatology across a number of dimensions
 Virtually eliminates apparent comorbidity
(First, 2005b)

29. ADVANTAGES OF DIMENSIONAL APPROACH
 Individual who presents with depression, anxiety, and
social avoidance
 Using the DSM-5 categorical system, criteria might be
met for three diagnoses
 A dimensional approach may simply indicate that the
person has elevated values on the depression, anxiety
and social avoidance dimensions

30. ADVANTAGES OF DIMENSIONAL APPROACH
 Dimensional approach avoids setting of a particular
thresholds for distinguishing between pathology and
normality
 Categorically individual has major depressive
disorder only if the threshold of five depressive
symptoms is met or exceeded
 Dimensional approach might say that the person is
high on the depression dimension

31. ADVANTAGES OF DIMENSIONAL APPROACH
 Research studies using dimensional scales have greater
power to detect differences in groups
(Cohen, 1983; Kraemer et al., 2004)
 Continuous dimensions more closely model the lack of
sharp boundaries between disorders and between
disorder and normality
 Facilitate research into the underlying etiology and
path-physiology of mental disorders
(Goldberg, 1996; Smoller & Tsuang, 1998)

32. ADVANTAGES OF DIMENSIONAL APPROACH
 Dimensions can be helpful in indicating the severity
of the disorder
 The range of appropriate treatments is related to the
severity of the disorder
 Cognitive therapy by itself would not be an
appropriate option for the treatment of severe forms
of major depressive disorder
(Andrews et al., 2007)

33. DISADVANTAGES OF DIMENSIONAL APPROACH
 Clinicians are accustomed to thinking in terms of
diagnostic categories
 Existing knowledge base about the presentation,
etiology, epidemiology, course, prognosis, and
treatment is based on these categories
 Decisions about the management of individual patients
are easier to make if the patient is thought of as having
a particular disorder
(First, 2005a)

34. DISADVANTAGES OF DIMENSIONAL
APPROACH
 The value of dimensions in terms of communicating
information from one clinician to another is likely to
be quite limited
 As Phillips (2013) noted in his review of The
Conceptual Evolution of DSM-5 (Regier et al., 2011),
one clinician communicates with another by saying
something like, ‘this is a bad case of depression and
so far intractable to treatment,’ not by saying, ‘on
dimensional scales x, y, and z the patient has such
and such scores’

35. VALIDITY
 It is defined as “well founded and applicable; sound and
to the point; against which no objection can fairly be
brought”
 When applied to measuring instruments:
 “validity refers to how well the instrument measures
what it is supposed to measure”
 When applied to a disease entity such as bacterial
pneumonia
 “validity refers to the evidence that bacteria is the
cause”

36. TYPES OF VALIDITY
 The types of validity currently employed in the
context of psychiatric diagnosis
1. Content
2. Criterion
3. Construct
4. Predictive

37. CONTENT VALIDITY
 Content validity refers to the degree to which an empirical
measurement reflects a specific domain of content
 In medicine and psychiatry, clinicians agree on important
features that make up a disease, a syndrome, or a
disorder
 Psychiatrists agree that a patient with schizophrenia has
delusions, hallucinations, disorganization, and bizarre
behavior
 The items that represent the domain or disorder are
derived from the consensus of experts in the field

38. ADVANTAGES OF CONTENT VALIDITY
 Content validity facilitates communication among
clinicians
 It provides an initial framework for further validation
 The worldwide use of the DSM and ICD diagnostic
criteria reflects great progress with regard to content
validity
 Clinicians across the globe use the same nomenclature
of mental disorders

39. CRITERION VALIDITY
 Criterion validity is measuring something that is
external to the measuring instrument itself called the
criterion
 Physicians agree that DM has four main symptoms:
 Polyuria, polyphagia, polydipsia, and unexplained
weight loss (content validity)
 In criterion validity, an external measure is used to
validate the diagnosis that is made by content validity
(e.g Fasting blood sugar)

40. CRITERION VALIDITY IN PSYCHIATRY
 A biological marker was defined by Buchsbaum as a
measurable indicator of a disease
 Several biological markers have been studied in
psychiatry:
1. Platelet monoamine oxidase (MAO)
2. Dexamethasone suppression test
3. Metabolites of serotonin and noradrenaline in the
cerebrospinal fluid
 No single biological marker has been unequivocally
identified as a marker for mental disorders

41. LEAD STANDARD BY SPITZER
 Spitzer proposed the LEAD standard (longitudinal
evaluation)
 The LEAD standard gives best estimate diagnosis by
expert clinicians by utilizing all the available data over
time
 Limited use of LEAD:
1. The requirement of expert clinicians to make
independent assessments
2. Discuss diagnostic disagreement
3. Make a consensus diagnosis

42. CONSTRUCT VALIDITY
 Construct validity refers to the extent to which a particular
measure relates to other measures consistent with
theoretically derived hypotheses
 Construct of diagnosis of schizophrenia relies on the young age
onset, the presence of psychosis, the absence of organic cause
of psychosis, and positive family history of schizophrenia
 Robins and Guze actually were the first to articulate the
elements of construct validity in psychiatry

43. ROBINS AND GUZE FIVE PHASES TO ACHIEVE
VALID CLASSIFICATION
 In 1970 they proposed five phases to achieve valid
classification of mental disorders:
1. Clinical description 2.Laboratory study
3. Exclusion of other disorders 4.Follow-up study
5. Family study
 They applied the criteria to schizophrenia and concluded
that good prognosis schizophrenia is not a mild
schizophrenia but a different illness

44. CONSTRUCT VALIDITY
 Construct validity consisting of validity criteria, is
the core of psychiatry
 Clinicians should use as many validity criteria as
possible to improve the validity of their diagnosis
 Researchers and clinicians should utilize construct
validity to revisit and redefine content validity of
psychiatric disorders

45. PROCEDURAL VALIDITY
 Procedural validity refers to the adequacy of a new
diagnostic procedure in replacing or simulating some
existing procedure
 One may use a structured interview to replace the
existing procedure of an open ended interview by a
clinician
 It is very important to remember what Spitzer said:
 “Procedural validity speaks only to the issue of the
validity of the evaluation procedure and not to the
validity of the diagnostic categories themselves”

46. VALIDITY VS UTILITY
 A diagnostic category is said to possess utility if it
provides information about:
 Prognosis
 Likely treatment outcomes
 Testable propositions about biological and social
correlates

47. UTILITY IN PSYCHIATRIC CLASSIFICATION
 The term utility was first used by Meehl
 There is significant etiological and prognostic
homogeneity among patients belonging to a given
diagnostic group
 Assignment of a patient to a group has probability
implications which is clinically unsound to ignore

48. PROPOSAL TO IMPROVE THE VALIDITY
SKILLS OF CLINICIANS
 Aboraya and Compton proposed the acronym
DR.SEEK
 D= Data
 R= Reference definitions
 S= Standardized instruments
 E= Clinical experience
 E= External validators
 K=Knowledge to improve the accuracy of making
psychiatric diagnoses

49. RELIABILITY
 Reliability refers to the extent to which an experiment,
test, or any measuring procedure yields the same
results on repeated trials
 A valid measurement or a system is reliable by
definition
 There is no guarantee that a reliable system is also
valid
 Such a system could be reliably incorrect and would
therefore be invalid

50. RELIABILITY OF PSYCHIATRIC DIAGNOSIS
- SERIOUS CHALLENGE
 Dohrenwend described three generations of
psychiatric epidemiology studies since the
turn of the 20th century

51. FIRST GENERATION- FROM THE TURN OF THE
20TH CENTURY TO WORLD WAR II
 Clinicians were not interested in making psychiatric
diagnoses
 Dominance of psychoanalysis
 Traditional psychoanalytic thought considered
psychiatric diagnosis irrelevant
 American Psychiatry was influenced by Adolf Meyer
 A prominent psychiatrist and advocate of social
psychiatry

52.  Social psychiatrists feared that psychiatric nomenclature
would lead to ignoring or minimizing the importance of
environmental and social factors on the etiology of
mental illness
 Progress toward psychiatric nomenclature in this era
was minimal

53. SECOND GENERATION- FROM WORLD WAR II
TO THE PUBLICATION OF DSM-III IN 1980
 Psychiatric nomenclature and diagnosis expanded
with the publications of ICD and DSM
 Studies of this generation relied on direct interviews
with subjects
 Psychiatric nomenclature developed by the WHO and
APA was utilized
 Reliability of psychiatric diagnoses was studied
 Results were disappointing

54. RESULTS OF THE RELIABILITY STUDIES
 Sandifer, et al., conducted a study that involved 91
cases that were diagnosed by 10 experienced
psychiatrists
 The overall likelihood of a second opinion agreeing
with the first was 57%
 A review of six studies between 1956 and 1972 by
Spitzer and Fleiss showed that the reliability of
psychiatric diagnoses is a major problem

55. ROBERT SPITZER AND DSM-III
 American psychiatrists were dissatisfied with the 1975
ICD-9
 Robert Spitzer headed a group to develop DSMIII in
1980
 The DSM-III represented a benchmark in the history
of psychiatric nomenclature:
1. It included explicit and specific criteria of many
psychiatric disorders
2. Marked the beginning of psychiatric epidemiology
studies

56. THIRD GENERATION- FROM THE PUBLICATION
OF DSM-III IN 1980 TO THE PRESENT
 Publication of the DSM-III, DSM-IIIR, DSM-IV, DSM-
5 as well as the ICD-10
 Studies on the reliability of psychiatric diagnosis
expanded greatly
 The reliability of psychiatric diagnoses of this
generation has improved due to the use of:
1. Stringent design
2. Diagnostic criteria
3. Structured interviews

57. CAUSES OF UNRELIABILITY OF PSYCHIATRIC
DIAGNOSIS
 Ward, et al., conducted a study to pinpoint the
reasons for diagnostic disagreement among
psychiatrists
 One experienced psychiatrist interviewed the patient
first and a second psychiatrist interviewed the
patient after a resting period of few minutes

58. CAUSES OF UNRELIABILITY OF PSYCHIATRIC
DIAGNOSIS
 After the second interview, both psychiatrists met,
discussed their diagnosis and established reasons for
disagreement
 The three main reasons for diagnostic disagreement
were:
1. Inconstancy of the patient (5%)
2. Inconstancy of the clinician (32.5%)
3. Inadequacy of the nomenclature (62.5%)

59. PATIENT FACTORS- PATIENT’S PSYCHOLOGICAL
STATE
 Patients may forget important information
 Patients unable to provide useful information
 Patients may omit information due to shame, denial,
fear of legal consequences
 Patients with personality disorders may make an
effort to manipulate the clinician

60. PATIENT FACTORS—THE USE OF PROXY
INFORMATION
 Clinician has to depend on proxy information
 The individual providing the proxy information may
have a vested interest in minimizing or exaggerating
elements of the history

61. ATYPICAL PRESENTATIONS OF PSYCHIATRIC
DISORDERS
 Typical presentation can be defined as the psychiatric
disorder that meets the criteria specified in the DSM
or the ICD manuals
 Majority of patients do not fit the classic psychiatric
diagnoses
 Diagnostician is forced to choose among the
categories

62. CLINICIAN FACTORS—THE CLINICIAN
INTERVIEW
 Clinicians with good interviewing skills establish a
therapeutic rapport
 Most clinicians use an open form type of interview in
routine psychiatric evaluation
 The workload and time constraints of clinicians
 Clinicians are pressured by institutional requirements
and financial incentives to make diagnoses that
reimburse at a higher rate

63. CLINICIAN FACTORS—CLINICIAN TRAINING,
EXPERIENCE AND SCHOOL OF THOUGHTS
 The reliance on the patient’s subjective symptoms
 Clinician’s interpretation of the symptoms and the
absence of objective measure
 Use of clinical data derived from direct observation is
a core component in any mental status examination

64. STUDY: COOPER ET AL. (1972)
THE US-UK DIAGNOSTIC PROJECT
 The aim of the study was to investigate reliability of
diagnosis of depression and schizophrenia
 The British psychiatrists diagnosed the patients in the
interview to be clinically depressed twice as often
 The American psychiatrists diagnosed the same
patients to be suffering from schizophrenia twice as
often
 The results indicated that the same cases did not result
in similar diagnosis in the two countries
 Problems of reliability
 Cultural differences in interpretation of symptoms and
making a diagnosis

65. CLINICIAN FACTORS— PSYCHIATRIC
NOMENCLATURE
 Ward, et al., found that inadequacy of the psychiatric
nomenclature is the main reason for diagnostic
unreliability (62.5%)
 The dissatisfaction with the DSM-I and -II and ICD-9
sparked major efforts by prominent psychiatrists and
researchers and eventually led to the publication of
the DSMIII in 1980

66. EVOLUTION OF DSM-III
 The criteria developed by the St. Louis group (Feighner
criteria) included the diagnostic criteria for 15
psychiatric conditions
 Spitzer and others subsequently developed the
Research Diagnostic Criteria (RDC)
 RDC was an expansion and modification of the Feighner
criteria
 RDC included descriptions of 25 diagnostic categories

67. DSM-III AND RELIABILITY OF PSYCHIATRIC
DIAGNOSIS
 APA Task Force on Nomenclature and Statistics
recommended using diagnostic criteria and categories
that can serve both research and clinical purposes
 To meet this goal, the Research Diagnostic Criteria
(RDC) was expanded and modified and resulted in the
publication of DSM-III in 1980
 Due to its use of specific, clear, and detailed criteria for
mental disorders, the DSM-III was accepted, preferred,
and used worldwide over the ICD-9

68. CONTROVERSIES
 Dimensional versus Categorical
Approaches Towards Classification
 At present the research community is not unified in its
opinion regarding the categorical–dimensional debate
 Personality disorder researchers favor replacing the
categorical system with a dimensional approach
 There has not been much discussion on extending the
dimensional approach to AXIS I disorders

69. PAUL MEEHL'S TAXOMETRIC ANALYSIS
 Taxometric analysis is a statistical method of examining
whether the interrelationships among the defining
features of a disorder better fit a dimensional or
categorical model
 Nick Haslam reviewed studies applying taxometric
analytic methods to different disorders
 He suggested that some disorders are more categorical
in nature whereas other disorders are dimensional
 Absence of clear-cut superiority of a dimensional
approach
 The categorical system seems appropriate at this time

70. SEPARATE DISORDERS VERSUS SUBTYPES
 Arthur C. Houts has criticised DSM of the increasing
number of disorders listed in each successive edition
 Disorders are being created that had previously not
been recognized as pathology
 This is indicative of a lack of scientific progress
 Wakefield concluded that the greater number of
diagnoses listed in successive DSMs represented
greater specification rather than diagnostic discoveries

71. LUMPERS VS SPLITTERS
 Debate within the field between the so-called
“lumpers,” who favor broader categories, and the
“splitters,” who favor sub-classification
 Researchers are more likely to benefit from
embracing the splitters approach
 It is easier to publish findings demonstrating that a
method of sub-classification is associated with
statistically significant differences

72.  Many research articles suggest the validity of diagnostic
and (sub)classification distinctions
 The principles guiding the incorporation of these
distinctions into a classification of disorders are
unwritten
 Some resulting questions include:
1. When is a syndrome sufficiently distinct from its near
neighbors to warrant being considered a separate
disorder?
2. When is the heterogeneity among members of a
disorder sufficient to warrant subdividing the group
into more homogeneous subgroups (i.e., subtyping)?

73. CONTROVERSIES
 L. Wittgenstein commented that
the classifications in Psychiatry are
as if one were to classify clouds by
their shape
 Clouds have fuzzy boundaries, tend
to merge imperceptibly and drift by
invisible air currents
 Observation and measurement of
their movement predict, within a
margin of error, the weather, yet
the inner physical and chemical
structure of clouds is hidden to the
naked eye

74.  The conceptual outlines of syndromes and disease
entities tend to change with successive revisions of
their classification, relative to their utility for
predicting course, outcome and likely response to
available treatments, even if their inner biological and
psychological structure is not fully understood
 The quest for validity of our concepts continues

75.  E. Kraepelin stated in one of his last articles,
‘Patterns of Mental Disorder’
 “It is necessary to turn away from arranging
illnesses in orderly well defined groups, and to set
ourselves the undoubtedly higher and more
satisfying goal of understanding their essential
structure”

76. DISEASE VS DISORDER VS SYNDROME
 Psychiatric classifications classify disorders
 Status of concepts like “disease” and “disorder” remains
obscure
 Disease is an explanatory construct integrating
information about pathology and cause
 The typical progression of knowledge starts with the
identification of clinical manifestations (the syndrome)
 Understanding of the pathology and aetiology comes
much later
 There is no fixed point or agreed threshold beyond which
a syndrome can be said to be a disease
 The majority of the “disorders” in our current
classifications are syndromes

77. CONTROVERSIES
 Role of pharmaceutical companies in classification
 Consideration of functional brain imaging/
investigations as diagnostic criteria
 Considering Family History and Genetic Markers
as Diagnostic Criteria
 Financial Implications of Revising the
Classification

78. QUESTIONS FACED BY PSYCHIATRIC
NOSOLOGY
 Recurrent questions about the nosological status of the
brain and mind disorders that constitute the core of the
discipline
 Are we dealing with discrete entities or with graded
continuous phenomena to which we can apply cut-off
points to separate “pathology” from “normal variation”?
 What is the relationship between the clinical
manifestations of a disorder and the underlying brain
dysfunction, pathological processes or predisposing
genetic aberrations?

79. FUTURE OF CLASSIFICATION
 NIMH-sponsored Research Domain Criteria (RDoC)
project is intended to establish “a framework for
creating research classifications that reflect functional
dimensions stemming from translational research on
genes, circuits, and behavior”
 Represents a true paradigm shift in the classification
of mental disorders, moving away from defining
disorders

80. CONCLUSION
 None of the many attempts to re-shape the
nosology of the major psychiatric disorders has been
entirely satisfactory
 There can be no doubt that the classical nosological
hypothesis was a major step forward, introducing
order and parsimony in a field that had previously
been chaotic or arbitrarily subdivided

81. CONCLUSION
 The nosological hypothesis helped to bring into focus
issues which critics could oppose or endorse
 This contributed to a diversity of viewpoints that was
fruitful in a developing discipline called psychiatry
 A more fundamental re-thinking of the nosological
theory will require the development of a conceptual
framework that allows a better integration of clinical,
neurobiological, genetic and behavioural data

82. SUMMARY
 DEFINITION OF CLASSIFICATION
 GOALS/ PURPOSE OF CLASSIFICATION
1. DENOMINATION
2. QUALIFICATION
3. PREDICTION
 ADVANTAGES OF PSYCHAITRIC CLASSIFICATION
1. Communicability
2. Predictability
 APPROACHES TO PSYCHIATRIC CLASSIFICATION:
1. Etiological Versus Descriptive
2. Syndrome Versus Symptom
3. Categorical Versus Dimensional

83. SUMMARY
 VALIDITY OF PSYCHIATRIC CLASSIFICATION:
1. Content
2. Criterion
3. Construct
4. Procedural
 RELIABILITY OF PSYCHIATRIC CLASSIFICATION:
1. First generation- 20th century to world war-I
2. second generation- 2nd world war to DSM-III
3. Third generation- DSM-III till Present
 CONTROVERSIES IN PSYCHIATRIC CLASSIFICATION:
1. Dimensional vs categorical approach
2. Separate disorders vs subtypes( Lumpers vs splitters)
3. Disease vs disorder
4. Use of genetic studies and functional neuroimaging

84. REFERENCES
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Jeffrey A. Lieberman, Michael B. First, Michelle B. Riba.–Fourth edition.
ISBN 978-1-118-84547-9 (cloth)
2. Kaplan & Sadock's Comprehensive Textbook of Psychiatry, 9th Edition;
Sadock, Benjamin J.; Sadock, Virginia A.; Ruiz, Pedro
3. The Reliability of Psychiatric Diagnosis Revisited: The Clinician’s Guide to
Improve the Reliability of Psychiatric Diagnosis; by Ahmed Aboraya, Md,
Drph; Eric Rankin, Phd; Cheryl France, Md; Ahmed El-missiry, Md,
Mrcpsych; Collin John. Psychiatry 2006 [ J A N U A R Y ],Page 42
4. The validity of Psychiatric Diagnosis Revisited: The Clinician’s Guide to
Improve the Reliability of Psychiatric Diagnosis; by Ahmed Aboraya, Md,
Drph; Eric Rankin, Phd; Cheryl France, Md; Ahmed El-missiry, Md,
Mrcpsych; Collin John. Psychiatry 2005 [ J A N U A R Y ],Page 42
5. Psychiatric classifications: validity and utility. Assen Jablensky. (World
Psychiatry 2016;15:26–31)
6. Indian Psychiatry and classification of psychiatric disorders. K. S. Jacob.
Indian J Psychiatry. 2010 Jan; 52(Suppl1): S104–S109.