Chapter 3: Classification and Diagnosis
In the realm of medicine and abnormal psychology, a diagnosis consists of a determination or
identification of the nature of a person’s disease or condition, or a statement of that finding.
o Diagnosis is made on the basis of a diagnostic system – rules for recognizing and grouping
various types of abnormalities.
Assessment – procedure through which info is gathered systematically in the evaluation of a
condition; this assessment procedure yields info that serves as the basis for a diagnosis.
o A mental health assessment may include:
interviews with the patient or their family,
medical testing, psychophysiological or psychological testing,
the completion of self-report scales
o A diagnostic system provides a number of criteria for a disorder;
If a certain number of these criteria or indications are present, the person is
diagnosed as having that particular disorder
Therefore, info from each of the assessment procedures contributes to the
formulation of a diagnosis.
THE PERFECT DIAGNOSTIC SYSTEM
The perfect diagnostic system would classify disorders on the basis of a study of presenting:
1. Symptoms – pattern of behaviours
2. Etiology – history of the development of the symptoms and underlying causes
3. Prognosis – future development of this symptoms
4. Responses to treatment
In the development of this diagnostic system, a large number of people would have been thoroughly
assessed psychologically and physically, in terms of feelings, thoughts, behaviours and various other
A thorough history would have been taken in order to understand how various features developed.
Various treatments would have been tried on groups of these patients, in a controlled fashion, to
assess their effectiveness.
Diagnostic categories would then be established by determining exactly which patterns of presenting
problems, with what kind of history, developed in which particular manner and responded
differentially to various treatments.
o Different symptom clusters, with dissimilar histories and differing normal progression,
would signal different syndromes
o Each sign or symptom would be found in only one diagnostic category; there would be no
overlap in the symptoms
o Treatment modalities would be so thoroughly developed that we would have at our disposal
a perfect cure for each diagnostic category, which would alleviate suffering for people who
fit that category with pinpoint accuracy
Practicalities preclude us from being able to systematically observe and measure many aspects of
functioning in large numbers of people, in a controlled way, over long periods of time Human beings are complex, rapidly changing, and multiple interacting events and processes
contribute to both adaptive and maladaptive behaviour.
The history of therapeutic interventions has also revealed how difficult it is to implement procedures
following strict scientific principles
Functions of a Good Classification System
1. Organization of clinical info It provides the essentials of a patient’s condition coherently and concisely
2. Shorthand communication It enhances the effective interchange of info, by clearly transmitting
important features of a disorder and ignoring unimportant features
3. Prediction of natural It allows accurate short-term and long-term prediction of an individual’s
4. Treatment It allows accurate predictions of the most effective interventions
5. Heuristic Value It allows the investigation and clarification of issues related to a problem
area. It also enhances theory-building
6. Guidelines for financial
support It provides guidelines to service needed, including payment of caregivers
THE HISTORY OF CLASSIFICATION
Classification is a fundamental activity of all humans – our understanding of classifying objects
becomes more sophisticated and refined as we grow older.
Classification is also of vital importance to science – the ability to categorize info allows scientists to
better identify and understand various phenomena.
World Health Organization decided to add mental health disorders to the International List of the
Causes of Death
o The list was then expanded to become the International Statistical Classification of Diseases,
Injuries, and Causes of Death (ICD)
ICD is a comprehensive listing of all diseases, including abnormal behaviour
The American Psychiatric Association published its own classification system; the Diagnostic and
Statistical Manual (DSM)
o The original DSM proved highly unsatisfactory – these two volumes were brief and
contained only vague descriptions of the diagnostic categories
o The current system contains 407 separate categories
o DSM-I and DSM-II were also greatly influenced by psychoanalytic theory, focused on internal
unobservable processes, were not empirically based, and contained few objective criteria.
o The system proved unreliable and as a result wasn’t unusual for clinicians to come up with
widely differing diagnoses for the same person.
DSMI-III version placed greater emphasis on empirical research
o These versions of the manual became atheoretical – they moved away from endorsing any
one theory of abnormal psychology, becoming more pragmatic as they moved to more
precise behavioural descriptions.
o To increase precision, they defined the required number of symptoms and specified how
long the symptoms had to last in order to meet the criteria DSM-III-R was developed to be polythetic – an individual could be diagnosed with a certain subset of
symptoms without having to meet all criteria
Multiaxial – Each DSM has five parts; each part is called an axis and contains different type of
information about the diagnosis
In addition, old data sets were reanalyzed and an additional 12 multisite field trials were conducted
to collect new data.
o These field trials:
were constituted to ensure participants represented diverse socio-economic,
cultural , and ethnic backgrounds
included 70 sites, and evaluated some 6000 patients
assessed the validity of the diagnoses, and set out to establish improved criteria
DSM-IV- was then revised to be even more scientifically sound and will integrate findings from
clinical research, animal studies, genetics, neuroscience, epidemiology, and cross-cultural research
o It’s the most widely used in Canada and US and is most used for research in psychopathology
DSM-IV-TR: A MULTIAXIAL APPROACH
Previously, clinicians typically rated patients on the most conspicuous aspect of their abnormal
o Beginning with DSM-III, the system acknowledged that a person’s life circumstances as a
whole need to be considered
o Diagnosticians were required to evaluate an individual on a broad array of info that might be
With DSM-IV-TR, clinicians assess patients under five different axes or a person’s condition
AXIS I: AXIS II: AXIS III:
CLINICAL DISORDERS PERSONALITY GENERAL MEDICAL CONDITIONS
Disorders usually first diagnosed in Paranoid Infectious and parasitic
infancy, adolescence Schizoid diseases
Delirium, dementia, amnesia, and Schizotypal Neoplasms
other cognitive disorders Antisocial Endocrine, nutritional, and
Substance-related disorders Borderline metabolic diseases
Schizophrenia and Other Psychotic Histrionic Diseases of the blood and
Disorders Avoidant blood-forming organs
Mood Disorders Dependent Disease of the nervous system
Anxiety Disorders Obsessive-compulsive and sense organs
Somatoform Disorders Diseases of the circulatory
Factitious Disorders system
Dissociative Disorders Diseases of the respiratory
Sexual and Gender Identity Disorders system
Eating Disorders Diseases of the digestive system
Sleep Disorders Diseases of the genitourinary
Impulse Control Disorders system
Other Conditions That May Be a
Focus on Clinical Attention Axis I – records most obvious disorders (describes what the patient has)
Axis II – focuses on the presence of generally less severe long-term disturbances, which may interfere
with a person’s life. (describes what the patient is)
o Usually individuals with these problems can function in jobs and relationships, albeit with
Axis III – covers any medical disorder that might be relevant to understanding or managing the case
o Recognizes that medical disorders;
may psychological disorders,
affect future development or treatment
Axis IV – collects info on the patient’s life circumstances, recognizing that individuals live within a
social milieu and that stressful social events might contribute to symptom onset.
Axis V – measures how well a person is able to cope with the circumstances related to his/her
o this info can be indicative of the need for treatment and of the persons’ coping mechanisms
and can assist in planning intervention
some critics contend that DSM-IV-TR does not really facilitate a comprehensive evaluation of
patients, and further suggest that the coding of all of the axes is rarely implemented in practice
CATEGORIES OF DISORDER IN DSM-IV-TR
DISM-IV-TR groups all of the disorders listed on either Axis I or Axis II into 15 categories, on the basis
of broad similarities in how they affect people, or how the people suffering from them may appear to
1. Disorders Usually First Diagnosed in Infancy, Childhood, or Adolescence
In this category are the intellectual, emotional, and physical disorders that typically begin before
Under general classification of “Attention Deficit and Disruptive Behaviour Disorders” are attention
deficit/hyperactivity disorder – the individual displays maladaptive levels of inattention,
hyperactivity, or impulsivity, or a combination of these;
o oppositional defiant disorder – there is a recurrent pattern of negativistic, defiant,
disobedient, and hostile behaviour toward authority figures
o conduct disorder – children persistently violate societal norms, rules, or the basic rights of
other diagnostic categories include:
o separation anxiety disorder – child becomes excessively anxious over the possibility of
separation from parents or significant others
o mental retardation – below-average intelligence with impairments in social judgment
which is identified at an early age
o autistic disorder – the child shows severe impairments in several areas of development,
including social interactions and communications
o learning disorders – the person’s functioning in particular academic skills areas is
significantly below average
o motor skills/communication disorders – the individual experiences significant
developmental problems with coordination or has difficulty with the reception or expression
of language o feeding and eating disorders
o tic disorders – the body moves repeatedly, quickly, suddenly, and/or uncontrollably (can
occur at any body part or can be vocal)
o elimination disorders – refer to the repeated passage of urine (enuresis) or feces
(encopresis) at inappropriate times and inappropriate places
frequently, children may develop disorders that are most commonly seen in adults, such as
depression or schizophrenia, and these are diagnosed according to the same basic criteria, with
minor amendments as those used for adults.
2. Delirium, Dementia, Amnesia, and Other Cognitive Disorders
Delirium – clouding of consciousness, wandering attention, and an incoherent stream of thought.
o It may be caused by several medical conditions as well as by poor diet and substance abuse.
Dementia – a deterioration of mental capacities, is typically irreversible, and is usually associated
with Alzheimer’s disease, stroke, several other medical conditions, and substance abuse.
Amnestic syndrome – involves impairment in memory when there is no delirium or dementia, and is
frequently linked to alcohol abuse.
3. Substance-Related Disorders
These disorders are brought about by the excessive use of a substance, which h can be defined as
anything that is ingested in order to produce a high, alter one’s senses, or otherwise affect functioning.
It is a considered a mental disorder when the use of these substances result in:
o Psychological, or
o Physical problems
People with this diagnosis may be unable to control or stop their use of substance and may have
become physically addicted to them.
On occasion, anxiety and mood disorders can result from substance abuse.
Such substance-induced mental disorders are categorized in the DSM-IV-TR along with the other
disorders whose symptoms they share.
Included in the group of substance abuse disorders are:
o Alcohol use disorders
o Opioid use disorders
o Amphetamine use disorders
o Cocaine use disorders
o Hallucinogen use disorders
4. Schizophrenia and Other Psychotic Disorders
Schizophrenia – severe debilitation in thinking and perception
o People with this disorder suffer from a state of psychosis, often characterized by delusions
(false beliefs) and hallucinations (false perceptions)
o People also lose the ability to care for themselves, relate to others, and function at work
Thought disorder is often prominent, demonstrated by:
o incoherent speech, loose associations (unconnected pieces of thoughts)
o inappropriate affect (such as laughing while at a funeral)
o and disorganized behaviour (such as public masturbation)
people in psychotic state have lost contact with the world and with others 5. Mood Disorders
The most prominent and prevalent mood disorder is major depressive disorder – a person is
extremely sad and discouraged, and displays a marked loss of pleasure from usual activities.
Clinically depressed people often have:
o severe problems sleeping,
o experience weight loss or gain,
o lack energy to do things,
o have difficulty concentrating,
o feel worthless, hopeless, and sometimes suicidal
mania – a condition where a person seems extremely