UNIT II: CLASSIFICATION OF MENTAL DISORDERS
Topic 1: Classification of Mental Disorders — Historical Development, DSM-5-TR and ICD-11
Introduction: Before We Start Naming Disorders
Imagine that three psychiatrists examine the same patient.
The patient has persistent sadness, loss of interest, disturbed sleep, poor concentration and withdrawal from other people.
One doctor calls the condition melancholia.
Another calls it a depressive reaction.
A third describes it as a psychoneurotic condition.
Are they talking about three different disorders, or about the same clinical problem using different languages?
This was one of the fundamental problems that eventually led to the development of standardized systems for classifying mental disorders.
Psychiatry did not begin with DSM-5-TR or ICD-11. These systems are the result of more than a century of attempts to answer a basic clinical and scientific question:
How can we describe and organize patterns of illness in a consistent way so that professionals can understand one another, researchers can study comparable groups, and health systems can record and respond to disease?
This is the starting point for understanding psychiatric classification.
1. What Do We Mean by Classification?
Classification means systematically organizing disorders or health conditions into groups according to agreed characteristics, definitions and criteria.
In mental health, classification helps us organize clinically significant patterns of:
Classification gives professionals a common language.
For example, when a trained clinician uses the term Major Depressive Disorder, the term refers to a defined diagnostic construct rather than simply meaning “the person is sad.”
However, classification is not the same thing as understanding the whole person.
A diagnosis may tell us what clinical pattern is present, but it does not by itself tell us:
why this particular person developed the problem,
what happened in their life,
what maintains the difficulty,
what their family believes,
what cultural meaning the symptoms have,
what strengths they possess,
or what treatment will work best for them.
Therefore:
Classification describes and organizes; clinical formulation explains the individual case.
This distinction should remain central throughout the study of DSM and ICD.
2. Why Was Classification Needed?
The need for classification developed from several practical problems.
Problem 1: Different names were used for similar conditions
Historically, mental disorders were described using terms that differed across physicians, hospitals, countries and theoretical traditions.
Problem 2: Similar names could mean different things
A diagnostic term did not necessarily have exactly the same meaning for every clinician.
Problem 3: Research needed common definitions
If one researcher defined depression differently from another, comparing research findings became difficult.
Problem 4: Governments needed reliable statistics
Health authorities needed to know how many people were dying from particular causes and, later, how many people were living with particular diseases.
Problem 5: Health systems needed standardized records
Hospitals, insurance systems, researchers and public-health agencies require standardized diagnostic terminology and coding.
Thus, classification gradually developed at the intersection of:
Clinical practice + statistics + hospital administration + research + public health
This history is important because ICD did not originally begin as a psychiatric manual, and DSM did not originally begin as the highly detailed clinical diagnostic manual students know today.
PART A — THE HISTORY OF ICD
3. Before ICD: The Story Begins with Mortality Statistics
The roots of ICD go back to the nineteenth century and, in fact, to an even earlier concern: how to record causes of death systematically.
In the nineteenth century, different countries and cities used different terms for causes of death. The same disease could be recorded under different names, while the same term could sometimes be used for different conditions.
This created a statistical problem.
If England, France and another country used different systems, how could governments compare mortality patterns?
This led to attempts to create an internationally applicable classification of causes of death.
4. 1853: William Farr and Marc d'Espine
A major early milestone came at the First International Statistical Congress in Brussels in 1853.
The Congress recognized the need for a uniform classification of causes of death and asked William Farr, an English medical statistician, and Marc d'Espine of Geneva to work toward an internationally applicable classification.
Their approaches were different.
Farr organized diseases largely according to broad groups and anatomical location, whereas d'Espine classified diseases according to their nature.
At the 1855 Paris Congress, their different approaches were brought together in a compromise classification.
The classification was subsequently revised in 1864, 1874, 1880 and 1886.
Although this system was not universally accepted, Farr's principle of organizing diseases partly according to anatomical location became an important foundation for later international classification.
Classroom discussion
Ask students:
“Why would two countries using different disease names create a problem?”
Expected discussion:
Because prevalence, mortality and health-service data could not be compared reliably.
This is the first idea students need to understand before hearing the word “ICD.”
5. 1891–1893: Jacques Bertillon
The next major step involved the French statistician Jacques Bertillon (1851–1922).
In 1891, the International Statistical Institute appointed a committee chaired by Bertillon to prepare a classification of causes of death.
Bertillon presented the committee's work at the International Statistical Institute meeting in Chicago in 1893, where it was adopted.
This became known as the Bertillon Classification of Causes of Death.
The classification was based partly on the system used in Paris and incorporated earlier principles associated with William Farr.
The importance of Bertillon's work lies not in psychiatry specifically, but in the creation of a more systematic and internationally comparable classification framework.
6. 1900: The First International Revision
The first International Conference for the Revision of the Bertillon or International List of Causes of Death was held in Paris in 1900.
This began the process of regular international revision.
Further revisions occurred during the early twentieth century.
For teaching purposes, the historical sequence can be remembered as:
1853 → Farr & d'Espine
↓
1891 → Bertillon committee
↓
1893 → Bertillon classification adopted
↓
1900 → First international revision
↓
Further revisions
↓
1948 → WHO and ICD-6
The WHO historical record identifies the nineteenth-century work as the foundation from which the modern ICD developed.
7. 1948: The Birth of the WHO-Era ICD
The most important turning point came in 1948.
The World Health Organization (WHO) was established in the post-war international health system, and the Sixth Revision of the International Classification was adopted.
This is extremely important:
Before ICD-6
The international system was primarily concerned with:
Causes of death
ICD-6 onward
The classification expanded to include:
Diseases + injuries + causes of death
This transformed the purpose of the system.
It was no longer only a mortality classification. It became a broader health classification.
This is why ICD-6 is often treated as the beginning of the modern WHO-era ICD.
WHO's official history records ICD-6 as the sixth revision, adopted and brought into effect in 1948.
8. ICD Revisions: The Complete Hierarchy
Students should know the sequence clearly.
| Revision | Adoption | Came into effect | Broad significance |
|---|
| ICD-6 | 1948 | 1948 | First WHO revision; expanded beyond causes of death to diseases and injuries |
| ICD-7 | 1956 | 1958 | Continued international revision and standardization |
| ICD-8 | 1966 | 1968 | Further refinement of disease classification |
| ICD-9 | 1976 | 1979 | Continued modernization and international comparability |
| ICD-10 | 1990 | 1993 | Major expansion and modernization of classification and coding |
| ICD-11 | 2019 | 2022 | Major conceptual, clinical and digital modernization |
These dates distinguish adoption from implementation. For example, ICD-11 was adopted by the World Health Assembly in May 2019 but came into effect as the basis for health reporting on 1 January 2022.
9. Why Did ICD Keep Changing?
Every revision responded to changes in medicine, science and health systems.
The broad progression was:
Need for comparable mortality statistics
↓
Need for broader disease statistics
↓
Need for better diagnostic terminology
↓
Need for improved international coding
↓
Need for modern clinical information
↓
Need for digital health interoperability
The later ICD revisions therefore became much more than lists of diseases.
They became systems for organizing health information.
10. ICD-10: An Important Milestone
ICD-10 was adopted in 1990 and came into effect in 1993.
It became one of the most widely used international health classifications.
It supported:
ICD-10 remained in use for many years, but scientific knowledge, clinical terminology and digital health requirements continued to develop.
This eventually led to ICD-11.
11. ICD-11: Why Was Another Revision Needed?
ICD-11 was not simply created because WHO wanted a newer number.
Several developments had occurred since ICD-10:
major advances in medical and mental-health science,
new clinical concepts,
improved understanding of relationships among disorders,
increased emphasis on clinical utility,
global health information requirements,
digital health systems,
electronic medical records,
and the need for better interoperability between health information systems.
WHO therefore designed ICD-11 as a digital-first, globally applicable classification.
12. ICD-11: Current System
ICD-11 was:
It is the WHO's current international classification system.
Importantly, ICD-11 is not only a psychiatric classification.
It is the global classification of:
Diseases + disorders + injuries + health conditions + causes of death
Mental, behavioural and neurodevelopmental disorders are included in Chapter 06.
WHO describes ICD as a common health language that supports recording, reporting, analysis and comparison of health information across countries and over time.
13. ICD-11: What Is New for Mental Health?
The mental-health section of ICD-11 was substantially reorganized.
The development process emphasized:
current scientific evidence,
clinical utility,
international applicability,
cultural considerations,
lifespan development,
and dimensional approaches where appropriate.
WHO's ICD-11 clinical guidance explicitly notes the use of dimensional approaches, including in personality disorders, and emphasizes culture-related guidance and a lifespan perspective.
Examples of important developments include the recognition or reorganization of conditions such as:
complex post-traumatic stress disorder,
gaming disorder,
prolonged grief disorder,
and revised personality-disorder classification.
14. ICD-11 CDDR: The Clinical Companion
There is one distinction that students must understand.
ICD-11 is the classification system.
In 2024, WHO published the:
Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural and Neurodevelopmental Disorders (ICD-11 CDDR).
The CDDR provides detailed clinical descriptions and diagnostic requirements to help qualified professionals identify and diagnose mental, behavioural and neurodevelopmental disorders.
WHO specifically states that the CDDR is complementary to the statistical reporting version of ICD-11. It was developed using current scientific evidence and clinical expertise and was field-tested internationally.
Easy classroom analogy
Think of:
ICD-11 = the classification map
ICD-11 CDDR = the clinical guide for using that map
PART B — THE HISTORY OF DSM
15. DSM Did Not Begin with DSM-I
Now we move to the DSM.
The first DSM was published in 1952, but the story begins earlier.
The American psychiatric classification system developed partly because the United States needed a systematic way to collect information about mental illness and to standardize psychiatric diagnoses.
Therefore, just as ICD had statistical roots, DSM also had statistical and administrative roots.
16. 1840: Early U.S. Mental-Health Statistics
One early milestone was the 1840 U.S. census, which attempted to record the frequency of “idiocy/insanity.”
This was not a modern diagnostic system.
It was essentially an attempt to collect population statistics.
By the 1880 census, several categories of mental disorder were being distinguished, including terms such as:
mania,
melancholia,
monomania,
paresis,
dementia,
dipsomania,
and epilepsy.
The terminology reflects the psychiatric knowledge of that historical period and should not be interpreted using modern diagnostic meanings.
The important lesson is:
Early psychiatric classification was initially driven partly by the need to count and organize cases.
APA's historical account traces the early U.S. classification effort back to the 1840 census.
17. 1917–1918: Statistical Manual for Mental Hospitals
A major development occurred in 1917–1918.
The American Medico-Psychological Association, together with the National Commission on Mental Hygiene, developed a standardized system for collecting information from mental hospitals.
This became the:
Statistical Manual for the Use of Institutions for the Insane
The system was primarily administrative and statistical, although it increasingly had clinical usefulness.
This distinction is important:
It was not yet DSM.
It was a precursor.
Over time, psychiatric classification in the United States became more clinically oriented.
18. 1940s: World War II and Medical 203
The Second World War created a new psychiatric challenge.
Military psychiatrists encountered large numbers of soldiers experiencing psychological reactions to combat, stress, trauma and military conditions.
The existing hospital-oriented classifications were not sufficient for all these situations.
The U.S. military therefore developed classification approaches for service personnel, including Technical Medical Bulletin 203, commonly known as Medical 203.
This system was influenced by the work of psychiatrists such as William C. Menninger and by the broader American psychiatric tradition.
The wartime experience had an important consequence:
Psychiatric classification increasingly needed to describe not only severe chronic psychiatric illness but also psychological reactions occurring in response to life circumstances and stress.
This experience influenced the development of DSM-I.
19. DSM-I — 1952
Now we arrive at the first actual DSM.
DSM-I
Published: 1952
Publisher: American Psychiatric Association
The first Diagnostic and Statistical Manual of Mental Disorders was developed by the APA Committee on Nomenclature and Statistics.
It was influenced by earlier American classification systems and by the international ICD framework, particularly ICD-6.
DSM-I contained approximately 102 diagnostic categories.
Its conceptual language reflected the psychiatric thinking of the time.
A prominent term was:
“Reaction”
Examples included:
schizophrenic reactions,
psychotic reactions,
psychophysiologic disorders,
psychoneurotic disorders,
personality disorders,
transient situational personality disorders.
Why was DSM-I important?
Because it created a standardized psychiatric classification specifically for the United States and provided a common diagnostic language for psychiatric practice.
But what was its limitation?
Its conceptual framework was strongly influenced by psychodynamic and psychobiological thinking, and many diagnostic descriptions were not as operationalized or explicit as later systems.
20. DSM-II — 1968
DSM-II
Published: 1968
DSM-II revised and expanded DSM-I.
One memorable change was the removal of the word “reaction” from diagnostic names.
Thus, the terminology moved away from the DSM-I style of “schizophrenic reaction” and toward more conventional diagnostic terminology.
DSM-II still reflected considerable psychodynamic influence and did not yet provide the detailed operational criteria that would later become characteristic of DSM-III.
Important historical connection
DSM-II was published in the same year that ICD-8 came into effect.
The development of DSM and ICD was increasingly coordinated because international diagnostic compatibility was becoming more important.
21. The Big Problem Before DSM-III: Reliability
Now comes one of the most important teaching moments.
Imagine two psychiatrists assessing exactly the same patient.
Psychiatrist A says:
“Depressive disorder.”
Psychiatrist B says:
“Personality disorder.”
Psychiatrist C says:
“Anxiety-related condition.”
If different trained professionals frequently reach different conclusions about the same clinical presentation, what is the problem?
The problem is diagnostic reliability.
Psychiatry faced increasing concern that diagnostic decisions were not sufficiently consistent.
Researchers needed clearer criteria.
Clinicians needed clearer diagnostic definitions.
Patients needed more reliable diagnostic communication.
This historical problem set the stage for the most influential revision in DSM history.
22. DSM-III — 1980: The Major Turning Point
DSM-III
Published: 1980
DSM-III represented a major transformation in psychiatric classification.
It was strongly associated with Robert Spitzer, who chaired the DSM-III Task Force.
The central goals included improving:
DSM-III introduced much more explicit diagnostic criteria.
It also introduced the famous multiaxial diagnostic system.
The conceptual shift
Earlier systems were more strongly influenced by broad theoretical formulations.
DSM-III moved toward:
“What specific symptoms and criteria are present?”
rather than relying as heavily on:
“Which broad psychological theory explains this person?”
This is sometimes described as the movement toward a more atheoretical or descriptive approach to diagnosis.
It did not mean that theories disappeared.
It meant that diagnostic criteria were designed to be more observable and reproducible across theoretical orientations.
Why DSM-III matters so much
If students remember only one historical turning point, it should be:
DSM-III = the major shift toward explicit, operationalized diagnostic criteria and improved diagnostic reliability.
APA's history specifically identifies explicit diagnostic criteria and the multiaxial assessment system as important features of DSM-III.
23. DSM-III's Multiaxial System
DSM-III introduced a five-axis system that continued into DSM-IV.
Students often memorize the axes, but they should understand why they existed.
The purpose was to ensure that clinicians considered more than the primary psychiatric diagnosis.
Axis I
Clinical disorders
Axis II
Personality disorders and intellectual disability
Axis III
General medical conditions
Axis IV
Psychosocial and environmental problems
Axis V
Global Assessment of Functioning (GAF)
The underlying idea was:
A person's mental-health condition cannot be understood completely by looking only at one psychiatric diagnosis.
This was an important conceptual step toward a broader clinical formulation.
24. DSM-III-R — 1987
DSM-III-R
Published: 1987
The “R” means Revision.
Why was a revision necessary?
Experience with DSM-III revealed:
inconsistencies,
problems with some criteria,
unclear diagnostic boundaries,
and areas requiring clarification.
Therefore, DSM-III-R refined and corrected the system.
This teaches us another important principle:
Classification systems are revised because clinical use reveals problems that were not always obvious during initial development.
APA's historical account specifically identifies inconsistencies and unclear criteria as reasons for the DSM-III-R revision.
25. DSM-IV — 1994
DSM-IV
Published: 1994
DSM-IV represented another major stage in the evolution of classification.
The development process lasted approximately six years and involved more than 1,000 individuals and numerous professional organizations.
A major emphasis was placed on empirical evidence and literature review.
The aim was to ensure that changes to the classification were supported by the available research.
DSM-IV therefore represents an important movement toward:
evidence-informed psychiatric classification
Changes included:
addition of some disorders,
deletion of some categories,
reorganization of others,
revision of diagnostic criteria,
and updating of descriptive material.
26. DSM-IV-TR — 2000
DSM-IV-TR
Published: 2000
Here students often make a mistake.
TR = Text Revision
DSM-IV-TR was not equivalent to creating an entirely new DSM.
The major purpose was to update:
The basic DSM-IV diagnostic criteria were largely retained.
Therefore:
DSM-IV → major edition
DSM-IV-TR → text revision
27. DSM-5 — 2013
DSM-5
Published: 2013
DSM-5 was a major new edition.
The development process began around 2000, and in 2007 APA established the DSM-5 Task Force and 13 disorder-area work groups.
DSM-5 introduced substantial changes.
Major changes included:
1. Removal of the formal five-axis system
The Axis I–V structure was discontinued.
However, medical conditions, psychosocial factors and functioning remained clinically important.
2. Greater dimensional thinking
DSM-5 increasingly recognized that symptoms and severity can exist along continua.
3. Reorganization of chapters
Disorders were reorganized partly according to developmental and scientific relationships.
4. Spectrum concepts
Some previously separate disorders were conceptualized more strongly as related conditions along a spectrum.
A well-known example is:
Autism Spectrum Disorder
which brought together several previously separate pervasive developmental diagnoses under a spectrum concept.
5. Greater cultural and developmental attention
The manual incorporated greater attention to cultural context and developmental considerations.
Thus, DSM-5 did not simply add more disorders.
It represented a broader conceptual reorganization of psychiatric classification.
28. DSM-5-TR — 2022
DSM-5-TR
Published: March 2022
The current DSM is:
Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision
The “TR” again means:
Text Revision
DSM-5-TR was developed beginning in 2019 and involved more than 200 subject-matter experts.
The goal was primarily to update the text and evidence base following DSM-5 rather than create a completely new conceptual edition.
Major features include:
fully revised text,
updated scientific references,
clarification of selected diagnostic criteria,
updated ICD-10-CM codes,
greater attention to culture,
attention to sex and gender,
attention to suicide,
attention to forensic issues,
attention to racism and discrimination,
and non-stigmatizing language.
DSM-5-TR also introduced:
Prolonged Grief Disorder
and added symptom codes for:
APA reports that more than 200 experts contributed to the revision and that cross-cutting groups reviewed culture, sex and gender, suicide and forensic issues.
29. An Important Point: DSM-5-TR Is Not DSM-6
Students should be very clear about the numbering.
DSM-5
2013
↓
DSM-5-TR
2022
This is a text revision, not a new sixth edition.
Therefore, we do not currently say “DSM-6.”
APA continues to issue approved updates to DSM-5-TR. For example, APA lists updates released in 2022, 2023, 2024 and 2025.
30. DSM and ICD: Why Do Both Exist?
At this point students usually ask:
“If DSM and ICD both classify mental disorders, why do we need two systems?”
This is an excellent question.
The answer lies partly in their different origins and purposes.
DSM
Developed by the:
American Psychiatric Association
Its primary focus is:
classification and diagnosis of mental disorders.
ICD
Developed by:
World Health Organization
Its scope is:
all diseases, disorders, injuries and health-related conditions.
Mental, behavioural and neurodevelopmental disorders are one major component of ICD.
Therefore:
DSM is a specialized mental-disorder classification manual; ICD is the broader international health classification system.
31. Current Hierarchy: DSM-5-TR
Students should understand the internal structure of DSM-5-TR.
The DSM has three major components:
1. Diagnostic Classification
The official list of recognized mental disorders.
2. Diagnostic Criteria Sets
The specific criteria used to determine whether a diagnosis is appropriate.
These criteria generally specify:
required symptoms,
number of symptoms,
duration,
functional significance,
exclusions,
and other requirements.
3. Descriptive Text
The text provides information about:
diagnostic features,
associated features,
prevalence,
development and course,
risk and prognostic factors,
culture-related issues,
sex and gender considerations,
suicidal thoughts or behaviour,
functional consequences,
differential diagnosis,
and comorbidity.
This three-part structure is important because DSM is not simply a list of disorder names.
32. Current Hierarchy: ICD-11
ICD-11 is organized hierarchically.
At the broad level:
ICD-11
↓
Chapters
↓
Disease/disorder groupings
↓
Specific conditions
↓
Further diagnostic specificity and coding
Mental, behavioural and neurodevelopmental disorders are located in:
Chapter 06
Within this chapter, disorders are organized into broad groupings and increasingly specific categories.
WHO's current ICD-11 framework is designed to support both clinical documentation and population-level health reporting.
33. DSM-5-TR and ICD-11: Side-by-Side Comparison
| Feature | DSM-5-TR | ICD-11 |
|---|
| Full name | Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision | International Classification of Diseases, 11th Revision |
| Organization | American Psychiatric Association | World Health Organization |
| Origin | U.S. psychiatric classification | International health classification |
| Main focus | Mental disorders | All diseases and health-related conditions |
| Current major version | DSM-5-TR, 2022 | ICD-11, effective 2022 |
| Mental disorders | Entire manual | Chapter 06 |
| Main purpose | Psychiatric diagnosis and classification | Global health classification, recording and reporting |
| Diagnostic criteria | Explicit criteria sets | Clinical descriptions and diagnostic requirements through ICD-11 CDDR |
| Coding | Uses ICD-related codes; DSM-5-TR uses ICD-10-CM codes in U.S. context | WHO international coding system |
| Culture | Explicit cultural formulation and culture-related diagnostic guidance | Culture-related guidance incorporated throughout mental-disorder guidance |
| Dimensional approach | Increasingly used | Strongly incorporated in selected areas |
| Personality disorders | Categorical diagnoses retained with dimensional features | More explicitly dimensional/severity-based |
| Digital orientation | Primarily diagnostic manual | Digital-first international health classification |
| International health statistics | Not its primary function | Major function |
| Current clinical companion | DSM-5-TR text and criteria | ICD-11 CDDR, 2024 |
34. A Very Important Clarification About Coding
Students often hear:
“DSM and ICD are two completely separate systems.”
That is too simplistic.
The two systems have historically interacted.
DSM-5-TR uses ICD-10-CM codes in the U.S. clinical and billing environment.
ICD-11 is the WHO international classification.
Therefore, the diagnostic concept and the coding system should not be treated as exactly the same thing.
The code is a standardized identifier used for documentation and data purposes.
35. What Has Changed Across the History?
The entire history can be understood as a movement through several broad stages.
Stage 1: Counting illness
“How many people are dying from what?”
↓
Stage 2: Organizing diseases
“How can diseases be classified consistently?”
↓
Stage 3: Describing psychiatric disorders
“How can mental disorders be named and grouped?”
↓
Stage 4: Improving reliability
“Can different clinicians reach more consistent diagnoses?”
↓
Stage 5: Evidence-based revision
“Are our categories supported by research?”
↓
Stage 6: Dimensional and developmental thinking
“Do disorders exist as completely separate boxes, or are there continua and relationships among them?”
↓
Stage 7: Cultural and contextual understanding
“How do culture, development, gender, discrimination and context influence diagnosis?”
↓
Stage 8: Digital and global classification
“How can health information be recorded, shared and compared across modern health systems?”
This is the real story behind DSM and ICD.
36. Why Classification Is Still Controversial
Classification is useful, but it is not perfect.
1. Heterogeneity
Two people with the same diagnosis may look very different clinically.
2. Comorbidity
One person may meet criteria for several disorders.
3. Symptom overlap
The same symptom can appear in multiple disorders.
4. Cultural variation
A behaviour may be pathological in one context but culturally meaningful in another.
5. Stigma
A diagnostic label can sometimes become a social label.
6. Medicalization
There is continuing debate about the boundary between normal human distress and mental disorder.
7. Changing science
Today's classification may change as scientific knowledge develops.
Therefore:
DSM and ICD are scientific and clinical tools, not permanent descriptions of absolute natural categories.
37. A Teacher's Case Discussion
Case: “Which Diagnosis?”
A 20-year-old college student comes to the counselling centre.
She reports:
She says:
“I have been like this since my parents separated six months ago.”
Ask the class:
Question 1: Can we immediately say she has an anxiety disorder?
No.
Question 2: What else do we need to know?
Students should identify:
Question 3: Why do we need classification at all?
Because once the assessment is complete, a standardized diagnostic framework helps professionals communicate what clinical pattern is present.
Question 4: Does the diagnosis explain her whole life?
No.
The diagnosis is only one component of her clinical formulation.
This case allows the teacher to move naturally from:
Classification → diagnosis → assessment → formulation
which will connect beautifully with the next Unit III topic on identification and assessment.
38. Classroom Discussion: “What If There Were No DSM or ICD?”
Ask students:
“Suppose tomorrow all DSM and ICD categories disappeared. Could psychologists still treat clients?”
Students may initially say yes.
Then ask:
“How would a psychiatrist in Delhi communicate with a psychiatrist in London about the same patient?”
“How would researchers decide whether two studies investigated the same disorder?”
“How would governments estimate the mental-health burden?”
“How would hospitals maintain standardized records?”
This discussion helps students understand that classification is not merely an academic exercise.
It is part of the infrastructure of modern healthcare.
39. Classification Does Not Replace Clinical Judgement
One of the most important principles for counselling students is:
Do not turn diagnostic criteria into a self-administered checklist.
DSM criteria are intended for trained professionals using clinical judgement.
A person may experience:
anxiety,
sadness,
intrusive thoughts,
sleep problems,
or unusual perceptions
without necessarily meeting criteria for a mental disorder.
The clinician must consider:
Symptoms + duration + severity + context + impairment + exclusions + culture + developmental stage + medical/substance factors
Therefore:
Symptom ≠ diagnosis
and:
Diagnosis ≠ complete formulation
40. Classification and the Biopsychosocial Perspective
Suppose two people both meet criteria for major depressive disorder.
Person A
Recently lost employment, has financial stress, social isolation and marital conflict.
Person B
Has recurrent episodes, a strong family history, childhood adversity and longstanding cognitive vulnerabilities.
The diagnostic classification may be similar.
But the formulation is different.
Therefore:
DSM/ICD tells us what clinical pattern is being classified.
Case formulation tells us how that pattern developed and is maintained in this particular person.
This is especially important in counselling psychology because counselling is concerned not only with diagnosis but also with meaning, context, relationships, coping, strengths and change.
41. Strengths of DSM-5-TR and ICD-11
When used appropriately, classification systems provide several advantages.
Common language
Professionals can communicate using standardized terminology.
Diagnostic reliability
Explicit criteria can improve consistency between clinicians.
Research
Researchers can define study populations more systematically.
Epidemiology
Health authorities can estimate the burden of disease.
Treatment planning
Diagnosis can help organize clinical decision-making.
Referral and multidisciplinary communication
Psychologists, psychiatrists, physicians and other professionals can communicate more effectively.
Health policy
ICD in particular supports international health statistics and resource planning.
Educational value
Students can learn psychopathology through a structured framework.
42. Limitations
However, classification should never become mechanical.
The major limitations include:
Reductionism: A complex human experience may be reduced to a label.
Heterogeneity: People with the same diagnosis may be very different.
Comorbidity: Diagnostic categories frequently overlap.
Cultural limitations: Diagnostic interpretation requires cultural context.
Stigma: Labels can sometimes reinforce social stereotypes.
Changing boundaries: Diagnostic categories evolve as science develops.
Contextual neglect: A diagnosis can obscure social and environmental causes if used without formulation.
Thus:
Good clinical practice uses diagnosis as a tool, not as the identity of the client.
43. What a Counselling Student Should Finally Understand
By the end of this lecture, a student should be able to tell the story rather than simply memorize dates.
The story is:
People first needed a way to count disease and death.
↓
International statistical classification developed.
↓
Bertillon and earlier statisticians contributed to standardized mortality classification.
↓
The WHO-era ICD expanded the system from causes of death to diseases and injuries.
↓
Psychiatry simultaneously developed its own increasingly systematic classification in the United States.
↓
Early U.S. systems were largely statistical and institutional.
↓
DSM-I appeared in 1952.
↓
DSM-II revised the terminology in 1968.
↓
Diagnostic reliability became a major concern.
↓
DSM-III in 1980 introduced explicit criteria and a major new approach to diagnostic reliability.
↓
Later editions increasingly incorporated empirical evidence.
↓
DSM-5 in 2013 reorganized the system and increased dimensional, spectrum and developmental thinking.
↓
DSM-5-TR in 2022 updated the text, evidence, culture-related material, suicide/self-injury information and introduced Prolonged Grief Disorder.
↓
ICD simultaneously evolved from ICD-6 through ICD-10 to ICD-11.
↓
ICD-11 now provides a global, digital and clinically oriented health classification system, with mental, behavioural and neurodevelopmental disorders in Chapter 06.
↓
The 2024 ICD-11 CDDR provides detailed clinical guidance for diagnosing those conditions.
44. Quick Revision Timeline
DSM
1840 — Early U.S. mental-health statistics
1917–18 — Statistical system for mental hospitals
1940s — Wartime psychiatric classification and Medical 203
1952 — DSM-I
1968 — DSM-II
1980 — DSM-III
1987 — DSM-III-R
1994 — DSM-IV
2000 — DSM-IV-TR
2013 — DSM-5
2022 — DSM-5-TR
ICD
1853 — International Statistical Congress; Farr and d'Espine asked to develop uniform classification
1891 — Bertillon committee appointed
1893 — Bertillon classification adopted
1900 — First international revision conference
1948 — ICD-6; first WHO-era revision
1958 — ICD-7
1968 — ICD-8
1979 — ICD-9
1993 — ICD-10 becomes effective
2022 — ICD-11 becomes effective
2024 — ICD-11 CDDR published
2026 — Current ICD-11 release cycle continues with annual updates
WHO's release system now lists January 2026 as the latest ICD-11 release, illustrating an important point: ICD-11 is not a frozen book; the digital classification is maintained and updated over time.
45. Key Takeaways
Classification developed because professionals and health systems needed a common and systematic language for disease and mental disorders.
The history of ICD begins with nineteenth-century international attempts to standardize mortality statistics, not with psychiatry.
William Farr and Marc d'Espine contributed to early international classification efforts in the 1850s.
Jacques Bertillon's work in the 1890s became a major foundation for the International List of Causes of Death.
The WHO-era ICD began with ICD-6 in 1948.
The major WHO revisions were ICD-6, ICD-7, ICD-8, ICD-9, ICD-10 and ICD-11.
The DSM developed from American psychiatric statistical and hospital-classification systems.
DSM-I was published in 1952.
DSM-II was published in 1968.
DSM-III in 1980 was the major turning point toward explicit diagnostic criteria and improved diagnostic reliability.
DSM-III-R in 1987 corrected and refined DSM-III.
DSM-IV in 1994 strengthened the empirical basis of classification.
DSM-IV-TR in 2000 was primarily a text revision.
DSM-5 in 2013 introduced major structural and conceptual changes.
DSM-5-TR in 2022 is the current major DSM text revision, with updated evidence, culture-related material, suicide/self-injury information and Prolonged Grief Disorder.
ICD-11 became effective in 2022 and is the current WHO classification system.
The ICD-11 CDDR, published in 2024, provides detailed clinical descriptions and diagnostic requirements for mental, behavioural and neurodevelopmental disorders.
DSM and ICD are related but not identical.
Most importantly:
A diagnostic classification is a tool for understanding and communicating about a clinical condition. It is not a substitute for understanding the individual person.
Review Questions
Recall and understanding
Why did systems of disease classification develop?
What was the significance of the 1853 International Statistical Congress?
Who was Jacques Bertillon?
Why is 1948 an important year in ICD history?
When was DSM-I published?
What was the significance of Medical 203?
What major problem was DSM-III designed to address?
What does “TR” mean in DSM-5-TR?
When did ICD-11 come into effect?
What is the ICD-11 CDDR?
Analytical questions
Trace the historical development of ICD from nineteenth-century mortality statistics to ICD-11.
Trace the development of DSM from early U.S. statistical systems to DSM-5-TR.
Explain why DSM-III is considered a major turning point in psychiatric classification.
Compare the major purposes of DSM and ICD.
Explain how DSM-5 differs conceptually from earlier DSM editions.
Discuss the major features of ICD-11 mental-disorder classification.
Explain why psychiatric classification systems require periodic revision.
Discuss the strengths and limitations of DSM-5-TR and ICD-11.
Explain why diagnosis should not be equated with case formulation.
Discuss the relevance of classification systems for counselling psychologists.
Classroom case discussion
A 21-year-old student reports anxiety, low mood, insomnia and difficulty concentrating after a major family conflict. She says, “I think I have an anxiety disorder.”
Discuss:
Can symptoms alone establish a diagnosis?
What additional information would you assess?
What role would DSM-5-TR or ICD-11 play?
Why is cultural and contextual understanding necessary?
Why is diagnosis different from formulation?
References
American Psychiatric Association. (1952). Diagnostic and statistical manual of mental disorders. American Psychiatric Association.
American Psychiatric Association. (1968). Diagnostic and statistical manual of mental disorders (2nd ed.). American Psychiatric Association.
American Psychiatric Association. (1980). Diagnostic and statistical manual of mental disorders (3rd ed.). American Psychiatric Association.
American Psychiatric Association. (1987). Diagnostic and statistical manual of mental disorders (3rd ed., rev.). American Psychiatric Association.
American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). American Psychiatric Association.
American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev.). American Psychiatric Association.
American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). American Psychiatric Association Publishing.
American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.; DSM-5-TR). American Psychiatric Association Publishing.
American Psychiatric Association. (2025). DSM-5-TR updates and supplements. American Psychiatric Association.
Barlow, D. H., Durand, V. M., & Hofmann, S. G. (2018). Abnormal psychology: An integrative approach (8th ed.). Cengage Learning.
Butcher, J. N., Hooley, J. M., & Nock, M. K. (2023). Abnormal psychology (18th ed.). Pearson.
Clark, L. A., Cuthbert, B., Lewis-Fernández, R., Narrow, W. E., & Reed, G. M. (2017). Three approaches to understanding and classifying mental disorder: ICD-11, DSM-5, and the National Institute of Mental Health's Research Domain Criteria (RDoC). Psychological Science in the Public Interest, 18(2), 72–145.
Houts, A. C. (2000). Fifty years of psychiatric nomenclature: Reflections on the 1943 War Department Technical Bulletin, Medical 203. Journal of Clinical Psychology, 56(7), 935–967.
World Health Organization. (1948). International Statistical Classification of Diseases, Injuries and Causes of Death: Sixth Revision. World Health Organization.
World Health Organization. (1992). International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10). World Health Organization.
World Health Organization. (2019). International Classification of Diseases for Mortality and Morbidity Statistics (11th Revision). World Health Organization.
World Health Organization. (2024). Clinical descriptions and diagnostic requirements for ICD-11 mental, behavioural and neurodevelopmental disorders. World Health Organization.
World Health Organization. (2026). ICD-11 2026 release. World Health Organization.
Indira Gandhi National Open University. MPCE-011: Psychopathology. IGNOU.
Indira Gandhi National Open University. BPCC-111: Understanding Psychological Disorders. IGNOU.
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