Diagnosis and Classification in Clinical Psychology
In clinical psychology, the aim is to understand behaviors and feelings. Understanding them
helps us plan interventions and treatments. Part of that process is making an accurate mental
health diagnosis. Using a classification system helps psychologists describe and communicate
accurately the nature and intensity of various problems. The most predominant way
psychologists classify people is by diagnostic labels, and the classification system they use most
often in the United States is the Diagnostic and Statistical Manual of Mental Disorders,
currently in its fifth edition with text revised (DSM-5, American Psychiatric Association, 2013).
While clinicians in the United States often refer to the DSM-5, professionals worldwide rely on
an international classification system, the International Classification of Disease (ICD-10).
Note that your Article Review is due at the end of this week.
The weekly readings, the Article Review, and the week's discussions will support meeting our
Week Outcomes.
Week 3 Outcomes
At the end of this week, you will be able to:
• discuss the history of mental illness and the evolution of mental health diagnoses
over the years
• explain why classification systems are necessary in the study of psychopathology
• describe the basic features of the Diagnostic and Statistical Manual of Mental
Disorders, Fifth Edition (DSM-5)
Learning Resources
Carlin, E. & Clegg, J. (2017). History of mental health diagnoses. In A. Wenzel (Ed.), The sage
encyclopedia of abnormal and clinical psychology (Vol. 1, pp. 1660-1664). SAGE Publications,
Inc. doi: 10.4135/9781483365817.n668
Kogan, C., Burns, S. & Reed, G. (2017). International classification of diseases. In A. Wenzel
(Ed.), The sage encyclopedia of abnormal and clinical psychology (Vol. 1, pp. 1872-1875). SAGE
Publications, Inc. doi: 10.4135/9781483365817.n752
Regier, D. A., Kuhl, E. A., & Kupfer, D. J. (2013). The DSM-5: Classification and criteria
changes. World psychiatry : official journal of the World Psychiatric Association (WPA), 12(2),
92–98. https://doi.org/10.1002/wps.20050
Segal, D., Marty, M. & Coolidge, F. (2017). Diagnostic and statistical manual of mental disorders,
fifth edition (dsm-5). In A. Wenzel (Ed.), The sage encyclopedia of abnormal and clinical
psychology (Vol. 1, pp. 1093-1095). SAGE Publications, Inc. doi: 10.4135/9781483365817.n433
Speilman, R. M., Jenkins, W. J. & Lovett, M. D. (2020). 15.2 Diagnosing and classifying
psychological disorders. Psychology
2e. OpenStax. https://openstax.org/books/psychology/pages/15-2-diagnosing-and-classifying-
psychological-disorders
History of Mental Health Diagnoses
,Carlin, E. & Clegg, J. (2017). History of mental health diagnoses. In A. Wenzel (Ed.), The sage
encyclopedia of abnormal and clinical psychology (Vol. 1, pp. 1660-1664). SAGE
Publications, Inc. doi: 10.4135/9781483365817.n668
The history of mental health diagnoses has been marked by continual transformation and little
consistency. Although diagnoses and diagnostic systems have proliferated, one clear trend
emerges—the continually increasing scope of mental health diagnoses. This entry briefly
outlines these changes, beginning with a short précis of pre-Enlightenment forms of diagnosis,
turning then to the expansion in diagnostic scope accompanying the development of the mental
health disciplines, and then covering the major shifts in diagnostic philosophy among the
principal diagnostic systems of the 20th century.
Early Forms of Diagnosis
Although the disciplines of psychology and psychiatry have their origins in the 19th century, it is
common for histories of mental health to reference several ancient medical texts as early
examples of psychiatric diagnostics, as these texts contain descriptions of behavioral and
physical signs that would eventually come under the purview of psychiatry. Among these texts
are those describing Greco-Roman theories of humoral balance, most widely associated with
Hippocrates and Galen. The humoral tradition attributed health and illness, as well as individual
temperaments, to the composition of four bodily fluids (humors), such that an imbalance in the
humors produced malady (e.g., an excess of black bile resulted in melancholia). Humoral theory
was taken up by Indian Ayurvedic medicine, and so historians also refer to classic texts such as
the Charaka Samhita as early diagnostic tools. Physicians of the Islamic Golden age, such as Ibn
Sina and Al-Ghazali, are also often cited in histories of diagnosis, as is the Malleus Mallificarum,
a 15th-century Christian treatise detailing the existence, identification, and prosecution of
witchcraft. Such a listing is obviously and necessarily limited, as virtually every society has a
history of attempting to identify and address symptoms now associated with mental health
diagnosis (e.g., traditional Chinese medicine, ancient Egyptian medicine, a wealth of Shamanic
traditions).
The record of diagnostic attempts becomes more extensive, and more influential for modern
mental health diagnosis, in Enlightenment-era western Europe. Natural philosophers and
physicians of this era produced a wave of classification systems, employing a variety of
strategies for grouping and describing the “natural” world. Medical taxonomies generally
followed the patterns set by zoological classifications and botanical classifications in particular
(e.g., that of Carl Linnaeus). In these largely biological models, each expert proposed some
essential feature that served as the organizing principle for his own taxonomy. As a result, both
zoological and medical classifications were designed around a variety of (often incompatible)
criteria; diseases of the psyche could be grouped, for example, by theorized causal mechanism,
,by phenomenology, by symptoms, or by prognosis. Later, as medical practice became more
institutionalized, these theoretical distinctions became more functional as they were shaped by
the requirements of the clinical setting.
The Expanding Scope of Diagnosis
Through the late Enlightenment up to the present, this shaping of diagnostic practice is
characterized most clearly by an expanding scope of diagnosis—expanding both in the range of
societal sectors and institutions within its purview and in the volume of diagnostic complexity
and specificity. In the 18th century, medical classification of all kinds began to widen in scope
with the appearance of a specific taxonomic discipline—termed nosology by the English
physician Thomas Sydenham. Sydenham’s Nosologia Methodica (1768) was grounded in his
empirical observations and in the assumption that, like all products of nature, each disease was a
singular and discrete species; as such, it would present a uniform and consistent illness across all
patients. This represented a profound departure from the humorism of Hippocratic and Galenic
medicine, for which intra-individual factors were paramount and disease was a compositional
feature of the person, rather than a separate and unique entity. This individuated disease model
of illness provided a mechanism for diagnostic proliferation and specification, and it would later
become an important foundation in the nosological work of Emil Kraepelin.
At the turn of the 18th century, the specification of these individuated mental health diseases
was primarily arbitrated by physicians in the hospital setting. As the growth of “lunatic asylums”
in Europe toward the end of the 1700s gave way to a state-led effort at large-scale
institutionalization at the turn of the century, both the profession and the diagnostic systems of
psychiatry began to take shape within the hospital. The rise of the secular state contributed to the
expansion of both medical authority and administrative responsibility through the establishment
of public institutions, and it was in these institutions that physicians honed their psychological
concepts. French physician Philippe Pinel, for example, formed his classifications from
observation of the institutionalized patients at the Bicêtre Hospital.
As psychological practice grew and became more specialized, it was further consolidated under
the auspices of the state; in Britain, the 1845 Lunacy Act provided for the construction of a larger
network of public institutions and instated a centralized national authority to oversee them. This
state consolidation was instrumental in the proliferation and specification of diagnosis, as the
nascent analytical tools of statistics were an increasingly important feature of national
governance. Also, public institutions were required to document, track, and regularly report on
their patient populations. Such centralized record keeping necessitated the development of
standardized diagnostic labels. These flourished in European hospitals.
For mental health diagnosis, the move toward increasingly specific diagnostic systems, applied
in an increasingly wide range of settings, began to be fully realized with the rise of specialized
psychiatric diagnostic systems. The theoretical underpinnings of modern psychiatric diagnosis
are often traced to the work of Kraepelin, who urged a shift from symptom-centered groupings
to a “clinical” approach, which emphasized careful descriptive accounts of the course of illness
over time. Much of Kraepelin’s taxonomic work focused on categorizing psychosis, where the
prevailing thought in German psychiatry held that most forms of psychosis manifested different
, expressions of a unitary underlying disease. Kraepelin’s nosology, however, divided psychosis
into two main forms, distinguished primarily by prognosis—(1) manic depression (characterized
by mood and affect) and (2) dementia praecox (“precocious madness,” a progressive disease).
Kraepelin’s focus on descriptive accounts of prognosis was highly influential in Germany and
abroad and helped frame an emerging psychiatric taxonomy amenable to the increasing
specification of disease entities.
By the late 1800s, the need for such taxonomic specifications became acute as the practice of
psychiatry expanded beyond the walls of the hospital, taking on wealthy, self-referred private
clients whose complaints were varied. Neuroses, for example, formerly the domain of the
physician, were redefined by Sigmund Freud and Carl Jung and began to migrate to the growing
specialty. Psychiatric diagnosis itself also left the confines of the hospital and began to be
applied to “everyday” experiences. For example, neurasthenia (“exhaustion of the nervous
system”), a term coined by American psychiatrist George Miller Beard, described a condition
defined by a range of emotional and behavioral symptoms common in everyday settings.
Diagnostic categories thus proliferated as the scope of practice widened, a trend accelerated in
the increasingly standardized diagnostic systems of the 20th century.
Standardization
Diagnostic and Statistical Manual of Mental Disorders
In the mid-20th century, the center of gravity for mental health diagnosis moved to the United
States and to the Diagnostic and Statistical Manual of Mental Disorders (DSM). In its earliest
iterations, the DSM had a fairly limited reach, but by the advent of the modern manuals (DSM-
III to the present), the DSM had become the most widely used diagnostic system. This wide
adoption represented a radical consolidation of diagnostic systems and also paved the way for a
far greater expansion in diagnostic scope than ever before.
Consolidation
The original manual (DSM-I) describes its origin as continuous with the statistical manuals
(Statistical Manual for the Use of Institutions for the Insane) that spanned the first half of the
20th century. The diagnoses in these earlier manuals were much fewer than in late-century
manuals (only 22 in the original 1918 manual) and focused primarily on biological models of
illness and medical models of treatment. DSM-I, published in 1952, broke with this biological
model, drawing inspiration instead from a document known as Medical 203, a report produced
by a committee from the office of the Surgeon General of the United States (an unsurprising
source of inspiration, as the entire DSM-I committee served in the mental health divisions of the
Armed Services). Substantial portions of DSM-I are virtually identical to Medical 203, most of
the diagnostic categories are the same (or quite similar), and both documents share the same
diagnostic philosophy. That diagnostic philosophy reflected the increasingly psychodynamic
character of the mental health professions in the war years. Disorders were described as generic
groups, whereas diagnoses were termed reactions—a notion meant to characterize
psychopathology as a response to various distressing circumstances. The framers of DSM-II,
published in 1968, made an effort to remove some of the more obviously psychodynamic
In clinical psychology, the aim is to understand behaviors and feelings. Understanding them
helps us plan interventions and treatments. Part of that process is making an accurate mental
health diagnosis. Using a classification system helps psychologists describe and communicate
accurately the nature and intensity of various problems. The most predominant way
psychologists classify people is by diagnostic labels, and the classification system they use most
often in the United States is the Diagnostic and Statistical Manual of Mental Disorders,
currently in its fifth edition with text revised (DSM-5, American Psychiatric Association, 2013).
While clinicians in the United States often refer to the DSM-5, professionals worldwide rely on
an international classification system, the International Classification of Disease (ICD-10).
Note that your Article Review is due at the end of this week.
The weekly readings, the Article Review, and the week's discussions will support meeting our
Week Outcomes.
Week 3 Outcomes
At the end of this week, you will be able to:
• discuss the history of mental illness and the evolution of mental health diagnoses
over the years
• explain why classification systems are necessary in the study of psychopathology
• describe the basic features of the Diagnostic and Statistical Manual of Mental
Disorders, Fifth Edition (DSM-5)
Learning Resources
Carlin, E. & Clegg, J. (2017). History of mental health diagnoses. In A. Wenzel (Ed.), The sage
encyclopedia of abnormal and clinical psychology (Vol. 1, pp. 1660-1664). SAGE Publications,
Inc. doi: 10.4135/9781483365817.n668
Kogan, C., Burns, S. & Reed, G. (2017). International classification of diseases. In A. Wenzel
(Ed.), The sage encyclopedia of abnormal and clinical psychology (Vol. 1, pp. 1872-1875). SAGE
Publications, Inc. doi: 10.4135/9781483365817.n752
Regier, D. A., Kuhl, E. A., & Kupfer, D. J. (2013). The DSM-5: Classification and criteria
changes. World psychiatry : official journal of the World Psychiatric Association (WPA), 12(2),
92–98. https://doi.org/10.1002/wps.20050
Segal, D., Marty, M. & Coolidge, F. (2017). Diagnostic and statistical manual of mental disorders,
fifth edition (dsm-5). In A. Wenzel (Ed.), The sage encyclopedia of abnormal and clinical
psychology (Vol. 1, pp. 1093-1095). SAGE Publications, Inc. doi: 10.4135/9781483365817.n433
Speilman, R. M., Jenkins, W. J. & Lovett, M. D. (2020). 15.2 Diagnosing and classifying
psychological disorders. Psychology
2e. OpenStax. https://openstax.org/books/psychology/pages/15-2-diagnosing-and-classifying-
psychological-disorders
History of Mental Health Diagnoses
,Carlin, E. & Clegg, J. (2017). History of mental health diagnoses. In A. Wenzel (Ed.), The sage
encyclopedia of abnormal and clinical psychology (Vol. 1, pp. 1660-1664). SAGE
Publications, Inc. doi: 10.4135/9781483365817.n668
The history of mental health diagnoses has been marked by continual transformation and little
consistency. Although diagnoses and diagnostic systems have proliferated, one clear trend
emerges—the continually increasing scope of mental health diagnoses. This entry briefly
outlines these changes, beginning with a short précis of pre-Enlightenment forms of diagnosis,
turning then to the expansion in diagnostic scope accompanying the development of the mental
health disciplines, and then covering the major shifts in diagnostic philosophy among the
principal diagnostic systems of the 20th century.
Early Forms of Diagnosis
Although the disciplines of psychology and psychiatry have their origins in the 19th century, it is
common for histories of mental health to reference several ancient medical texts as early
examples of psychiatric diagnostics, as these texts contain descriptions of behavioral and
physical signs that would eventually come under the purview of psychiatry. Among these texts
are those describing Greco-Roman theories of humoral balance, most widely associated with
Hippocrates and Galen. The humoral tradition attributed health and illness, as well as individual
temperaments, to the composition of four bodily fluids (humors), such that an imbalance in the
humors produced malady (e.g., an excess of black bile resulted in melancholia). Humoral theory
was taken up by Indian Ayurvedic medicine, and so historians also refer to classic texts such as
the Charaka Samhita as early diagnostic tools. Physicians of the Islamic Golden age, such as Ibn
Sina and Al-Ghazali, are also often cited in histories of diagnosis, as is the Malleus Mallificarum,
a 15th-century Christian treatise detailing the existence, identification, and prosecution of
witchcraft. Such a listing is obviously and necessarily limited, as virtually every society has a
history of attempting to identify and address symptoms now associated with mental health
diagnosis (e.g., traditional Chinese medicine, ancient Egyptian medicine, a wealth of Shamanic
traditions).
The record of diagnostic attempts becomes more extensive, and more influential for modern
mental health diagnosis, in Enlightenment-era western Europe. Natural philosophers and
physicians of this era produced a wave of classification systems, employing a variety of
strategies for grouping and describing the “natural” world. Medical taxonomies generally
followed the patterns set by zoological classifications and botanical classifications in particular
(e.g., that of Carl Linnaeus). In these largely biological models, each expert proposed some
essential feature that served as the organizing principle for his own taxonomy. As a result, both
zoological and medical classifications were designed around a variety of (often incompatible)
criteria; diseases of the psyche could be grouped, for example, by theorized causal mechanism,
,by phenomenology, by symptoms, or by prognosis. Later, as medical practice became more
institutionalized, these theoretical distinctions became more functional as they were shaped by
the requirements of the clinical setting.
The Expanding Scope of Diagnosis
Through the late Enlightenment up to the present, this shaping of diagnostic practice is
characterized most clearly by an expanding scope of diagnosis—expanding both in the range of
societal sectors and institutions within its purview and in the volume of diagnostic complexity
and specificity. In the 18th century, medical classification of all kinds began to widen in scope
with the appearance of a specific taxonomic discipline—termed nosology by the English
physician Thomas Sydenham. Sydenham’s Nosologia Methodica (1768) was grounded in his
empirical observations and in the assumption that, like all products of nature, each disease was a
singular and discrete species; as such, it would present a uniform and consistent illness across all
patients. This represented a profound departure from the humorism of Hippocratic and Galenic
medicine, for which intra-individual factors were paramount and disease was a compositional
feature of the person, rather than a separate and unique entity. This individuated disease model
of illness provided a mechanism for diagnostic proliferation and specification, and it would later
become an important foundation in the nosological work of Emil Kraepelin.
At the turn of the 18th century, the specification of these individuated mental health diseases
was primarily arbitrated by physicians in the hospital setting. As the growth of “lunatic asylums”
in Europe toward the end of the 1700s gave way to a state-led effort at large-scale
institutionalization at the turn of the century, both the profession and the diagnostic systems of
psychiatry began to take shape within the hospital. The rise of the secular state contributed to the
expansion of both medical authority and administrative responsibility through the establishment
of public institutions, and it was in these institutions that physicians honed their psychological
concepts. French physician Philippe Pinel, for example, formed his classifications from
observation of the institutionalized patients at the Bicêtre Hospital.
As psychological practice grew and became more specialized, it was further consolidated under
the auspices of the state; in Britain, the 1845 Lunacy Act provided for the construction of a larger
network of public institutions and instated a centralized national authority to oversee them. This
state consolidation was instrumental in the proliferation and specification of diagnosis, as the
nascent analytical tools of statistics were an increasingly important feature of national
governance. Also, public institutions were required to document, track, and regularly report on
their patient populations. Such centralized record keeping necessitated the development of
standardized diagnostic labels. These flourished in European hospitals.
For mental health diagnosis, the move toward increasingly specific diagnostic systems, applied
in an increasingly wide range of settings, began to be fully realized with the rise of specialized
psychiatric diagnostic systems. The theoretical underpinnings of modern psychiatric diagnosis
are often traced to the work of Kraepelin, who urged a shift from symptom-centered groupings
to a “clinical” approach, which emphasized careful descriptive accounts of the course of illness
over time. Much of Kraepelin’s taxonomic work focused on categorizing psychosis, where the
prevailing thought in German psychiatry held that most forms of psychosis manifested different
, expressions of a unitary underlying disease. Kraepelin’s nosology, however, divided psychosis
into two main forms, distinguished primarily by prognosis—(1) manic depression (characterized
by mood and affect) and (2) dementia praecox (“precocious madness,” a progressive disease).
Kraepelin’s focus on descriptive accounts of prognosis was highly influential in Germany and
abroad and helped frame an emerging psychiatric taxonomy amenable to the increasing
specification of disease entities.
By the late 1800s, the need for such taxonomic specifications became acute as the practice of
psychiatry expanded beyond the walls of the hospital, taking on wealthy, self-referred private
clients whose complaints were varied. Neuroses, for example, formerly the domain of the
physician, were redefined by Sigmund Freud and Carl Jung and began to migrate to the growing
specialty. Psychiatric diagnosis itself also left the confines of the hospital and began to be
applied to “everyday” experiences. For example, neurasthenia (“exhaustion of the nervous
system”), a term coined by American psychiatrist George Miller Beard, described a condition
defined by a range of emotional and behavioral symptoms common in everyday settings.
Diagnostic categories thus proliferated as the scope of practice widened, a trend accelerated in
the increasingly standardized diagnostic systems of the 20th century.
Standardization
Diagnostic and Statistical Manual of Mental Disorders
In the mid-20th century, the center of gravity for mental health diagnosis moved to the United
States and to the Diagnostic and Statistical Manual of Mental Disorders (DSM). In its earliest
iterations, the DSM had a fairly limited reach, but by the advent of the modern manuals (DSM-
III to the present), the DSM had become the most widely used diagnostic system. This wide
adoption represented a radical consolidation of diagnostic systems and also paved the way for a
far greater expansion in diagnostic scope than ever before.
Consolidation
The original manual (DSM-I) describes its origin as continuous with the statistical manuals
(Statistical Manual for the Use of Institutions for the Insane) that spanned the first half of the
20th century. The diagnoses in these earlier manuals were much fewer than in late-century
manuals (only 22 in the original 1918 manual) and focused primarily on biological models of
illness and medical models of treatment. DSM-I, published in 1952, broke with this biological
model, drawing inspiration instead from a document known as Medical 203, a report produced
by a committee from the office of the Surgeon General of the United States (an unsurprising
source of inspiration, as the entire DSM-I committee served in the mental health divisions of the
Armed Services). Substantial portions of DSM-I are virtually identical to Medical 203, most of
the diagnostic categories are the same (or quite similar), and both documents share the same
diagnostic philosophy. That diagnostic philosophy reflected the increasingly psychodynamic
character of the mental health professions in the war years. Disorders were described as generic
groups, whereas diagnoses were termed reactions—a notion meant to characterize
psychopathology as a response to various distressing circumstances. The framers of DSM-II,
published in 1968, made an effort to remove some of the more obviously psychodynamic
