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DIAGNOSING PSYCHOLOGICAL DISORDERS:The categorical approach, Prototypical approach

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Abnormal Psychology ­ PSY404
VU
LESSON 16
DIAGNOSING PSYCHOLOGICAL DISORDERS
The term classification refers to any effort to construct groups or categories and to assign objects or people
to these categories or groups on the basis of their attributes, characteristics or relations. Methods of
classification include:
1.
Classical categorical system
2.
Dimensional system
3.
Prototypical approach
In order to classify the psychological disorders we need a classification system. The term classification refers
to process to construct categories and to assign people to these categories on the basis of their attributes or
relations. Classification in scientific context refers to taxonomy. It also refers to nomenclature, which
describes the names and labels that may make up a particular disorder such as schizophrenia or depression.
Classification is at the heart of every science. If we can not label and order objects or experiences or
behaviors scientists could not communicate with one another and our knowledge will not advance.
Therefore, we develop a system with which we could define or classify behavior. Abnormal psychology is
based on the assumption that a behavior is part of one category or disorder and not of another one.
Psychologists use three approaches or strategies to classify disorders:
1.
The categorical approach
2.
Dimensional approach
3.
Prototypical approach
The categorical approach
It was Kraepelin, the first psychiatrist to classify psychological disorders from a biological or
medical point of view. For Kraepelin in term of physical disorders, we have one set of causative factors
which do not overlap with other disorders. We have one defining criteria, which every body in the category
or in the group should meet.
Example  Schizophrenia
Dimensional Approach
A second strategy is a dimensional approach, in which we note the variety of cognitions, moods,
and behaviors with which the patient presents and quantify them on a scale. For example, on a scale of 1 to
10, a patient might be rated as severely anxious (10), moderately depressed (5), and mildly manic (2) to
create a profile of emotional functioning (10, 5, 2). Although dimensional approaches have been applied to
psychopathology, they are relatively unsatisfactory.
Prototypical approach
A third approach, for organizing and classifying behavioral disorders which is an alternative to the
first two. It is called a prototypical approach. It identifies some essential characteristics of a disorder and it
also allows for certain non-essential variations that do not necessarily change the classification. With this
approach classifying the disorder by different possible features or properties any candidate must meet (but
not all) of them to fall in that category. In depression, there are five important symptoms such as:
1.
Depressed mood all of the day
2.
Weight loss
3.
Insomnia
4.
Fatigue
5.
Feeling of worthlessness
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Abnormal Psychology ­ PSY404
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For a person might have three or four of the characteristics of the depression but not all five of them. Yet
we still diagnose the person as depressed.
Categories versus Dimensions
·  After a category has been defined, an object is either a member of the category or it is not. A
categorical approach to classification assumes that distinctions among members of different
categories are qualitative.
·  In other words, the differences reflect a difference in kind (quality) rather than a difference in
amount (quantity).
·  An alternative, scientists often employ a dimensional approach to classification--that is, one
that describes the objects of classification in terms of continuous dimensions.
·  Rather than assuming that an object either has or does not have a particular property, it may be
useful to focus on a specific characteristic and determine how much of that characteristic the object
exhibits.
From Description to Theory
·  Mental disorders are currently classified on the basis of their descriptive features or symptoms.
·  We need a classification system for abnormal behavior for two primary reasons.
·  First, a classification system is useful to clinicians, who must match their clients' problems with the
form of intervention that is most likely to be effective.
·  Second, a classification system must be used in the search for new knowledge.
Brief History of Classifying Abnormal Behavior
Brief Historical Perspective
·  Currently, two diagnostic systems for mental disorders are widely recognized.
·  1--One--the Diagnostic and Statistical Manual (DSM)--is published by the American Psychiatric
Association.
·  2--The other--the International Classification of Diseases (ICD)--is published by the World Health
Organization.
·  During the 1950s and 1960s, psychiatric classification systems were widely criticized. One major
criticism focused on the lack of consistency in diagnostic decisions.
·  Renewed interest in the value of psychiatric classification grew steadily during the 1970s,
culminating in the publication of the third edition of the DSM in 1980.This version of the manual
represented a dramatic departure from previous systems.
The DSM-IV-TR System
·  More than 200 specific diagnostic categories are described in DSM-IV-TR. These are arranged
under 18 primary headings.
·  The manual lists specific criteria for each diagnostic category.
·  The DSM-IV-TR employs a multiaxial classification system; that is, the person is rated on five
separate axes.
·  Each axis is concerned with a different domain of information.
·  Two are concerned with diagnostic categories and the other three provide for the collection of
additional relevant data.
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Abnormal Psychology ­ PSY404
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DSM is not a perfect document but this imperfect document gives valuable information. Each axis of DSM
provides an important piece of information related to a person's behavior. Each axis is like a piece of a
puzzle and when all the pieces or axes are put at the right places we get a complete picture.
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Table of Contents:
  1. ABNORMAL PSYCHOLOGY:PSYCHOSIS, Team approach in psychology
  2. WHAT IS ABNORMAL BEHAVIOR:Dysfunction, Distress, Danger
  3. PSYCHOPATHOLOGY IN HISTORICAL CONTEXT:Supernatural Model, Biological Model
  4. PSYCHOPATHOLOGY IN HISTORICAL CONTEXT:Free association, Dream analysis
  5. PSYCHOPATHOLOGY IN HISTORICAL CONTEXT:Humanistic Model, Classical Conditioning
  6. RESEARCH METHODS:To Read Research, To Evaluate Research, To increase marketability
  7. RESEARCH DESIGNS:Types of Variables, Confounding variables or extraneous
  8. EXPERIMENTAL REASEARCH DESIGNS:Control Groups, Placebo Control Groups
  9. GENETICS:Adoption Studies, Twin Studies, Sequential Design, Follow back studies
  10. RESEARCH ETHICS:Approval for the research project, Risk, Consent
  11. CAUSES OF ABNORMAL BEHAVIOR:Biological Dimensions
  12. THE STRUCTURE OF BRAIN:Peripheral Nervous System, Psychoanalytic Model
  13. CAUSES OF PSYCHOPATHOLOGY:Biomedical Model, Humanistic model
  14. CAUSES OF ABNORMAL BEHAVIOR ETIOLOGICAL FACTORS OF ABNORMALITY
  15. CLASSIFICATION AND ASSESSMENT:Reliability, Test retest, Split Half
  16. DIAGNOSING PSYCHOLOGICAL DISORDERS:The categorical approach, Prototypical approach
  17. EVALUATING SYSTEMS:Basic Issues in Assessment, Interviews
  18. ASSESSMENT of PERSONALITY:Advantages of MMPI-2, Intelligence Tests
  19. ASSESSMENT of PERSONALITY (2):Neuropsychological Tests, Biofeedback
  20. PSYCHOTHERAPY:Global Therapies, Individual therapy, Brief Historical Perspective
  21. PSYCHOTHERAPY:Problem based therapies, Gestalt therapy, Behavioral therapies
  22. PSYCHOTHERAPY:Ego Analysis, Psychodynamic Psychotherapy, Aversion Therapy
  23. PSYCHOTHERAPY:Humanistic Psychotherapy, Client-Centered Therapy, Gestalt therapy
  24. ANXIETY DISORDERS:THEORIES ABOUT ANXIETY DISORDERS
  25. ANXIETY DISORDERS:Social Phobias, Agoraphobia, Treating Phobias
  26. MOOD DISORDERS:Emotional Symptoms, Cognitive Symptoms, Bipolar Disorders
  27. MOOD DISORDERS:DIAGNOSIS, Further Descriptions and Subtypes, Social Factors
  28. SUICIDE:PRECIPITATING FACTORS IN SUICIDE, VIEWS ON SUICIDE
  29. STRESS:Stress as a Life Event, Coping, Optimism, Health Behavior
  30. STRESS:Psychophysiological Responses to Stress, Health Behavior
  31. ACUTE AND POSTTRAUMATIC STRESS DISORDERS
  32. DISSOCIATIVE AND SOMATOFORM DISORDERS:DISSOCIATIVE DISORDERS
  33. DISSOCIATIVE and SOMATOFORM DISORDERS:SOMATOFORM DISORDERS
  34. PERSONALITY DISORDERS:Causes of Personality Disorders, Motive
  35. PERSONALITY DISORDERS:Paranoid Personality, Schizoid Personality, The Diagnosis
  36. ALCOHOLISM AND SUBSTANCE RELATED DISORDERS:Poly Drug Use
  37. ALCOHOLISM AND SUBSTANCE RELATED DISORDERS:Integrated Systems
  38. SCHIZOPHRENIA:Prodromal Phase, Residual Phase, Negative symptoms
  39. SCHIZOPHRENIA:Related Psychotic Disorders, Causes of Schizophrenia
  40. DEMENTIA DELIRIUM AND AMNESTIC DISORDERS:DELIRIUM, Causes of Delirium
  41. DEMENTIA DELIRIUM AND AMNESTIC DISORDERS:Amnesia
  42. MENTAL RETARDATION AND DEVELOPMENTAL DISORDERS
  43. MENTAL RETARDATION AND DEVELOPMENTAL DISORDERS
  44. PSYCHOLOGICAL PROBLEMS OF CHILDHOOD:Kinds of Internalizing Disorders
  45. LIFE CYCLE TRANSITIONS AND ADULT DEVELOPMENT:Aging