Categorical approaches to classification have also dominated psychiatry, in spite of the fact that they often do not fit. Placing a problem into a category requires that the category have strong boundaries, like a box. Categories assume common causal factors for those in the category, and advocates of categories blame fuzzy boundaries on lack of knowledge. In fact, many psychiatric problems area matter of degree. To the extent that the underlying nature of the problem is categorical, a good system requires that the boundaries are defined so they match nature (like cutting "at the joint"). Clinicians have tended to champion this model, preferring to ignore the problem of degree in their diagnostic labels.
Dimensional models propose a limited number of important attributes, and then describe dysfunction by placing the individual along each dimension to represent the strength of the attribute for that person. Dimensions can be formed in different ways. For example, a dimension can reflect amount of a single attribute or reflect degree between two opposing attributes. Thus, instead of categorizing a child as "conduct disordered," a therapist might rate the child as high on anger/hostility, low on impulse control, etc. Dimensional models are readily available for a variety of problems, especially childhood disorders. However, they are essentially unused by any major diagnostic system
The prototypical model is most similar to the categorical model in that it uses categories, but it explicitly allows for fuzziness. Basically, classification relies on idealized lists of criteria that tend to co-occur in the group of those so diagnosed. The idealized list defines the prototype, but diagnostic rules require only some subset of the list, thereby explicitly conceding that many will not fit the entire list. The major diagnostic systems of today rely on this fuzzy categorical approach, as well as traditional categorization. With this approach it is possible for two individuals to receive the same diagnosis but not share a single major symptom.
Reliability and Validity
Reliability refers to the reproducibility or consistency of results. Validity refers to the meaning of the diagnosis. That is, is the diagnosis meaningful or accurate?
Reliability refers to the reproducibility or consistency of results. For a diagnosis to be reliable, different diagnosticians would have to mostly give the same diagnosis to the same person, and people with similar symptoms would have to be diagnosed the same. A diagnosis must have reasonable reliability before it can be valid (that is, a random diagnosis cannot be useful.)
Diagnostic and Statistical Manual of Mental Disorders. As such, the manual provides two types of information: a description of diagnostic criteria, and descriptions of other information, including associated features, causal factors, comorbidity, prevalence, and other disorders to which a specific disorder is most like or with which it is confused.
DSM IV approach
- I Clinical Disorders.
- II Personality Disorders and Mental Retardation.
- III General Medical Conditions.
- IV Psychosocial and Environmental Problems.
- V Global Assessment of Functioning.
charges that diagnoses convey limited understanding, that they sometimes imply attributes that do not fit the person, and that they tend to persist and stigmatize the person even after problems have disappeared.
Brief Psychiatric Rating Scale
Behavior rating scale used to assess the severity of patient problem areas such as guilt feelings and preoccumation with health.
Systematic evaluation and measurement of psychological, biological and social factors in a person presenting with a possible psychological disorder.
Concurrent validity, Construct validity, Content validity
Concurrent: Condition of testing in which the results from one test correspond to the results of other measures of the same phenomenon
Construct: Degree to which signs and symbols used to categorize a disorder relate to each other while differing from those for other disorders
Content: Degree to which the characteristics of a disorder are a true sample of the phenomenon in question
False negative and false positive.
Negative: Assessment error in which no pathology is noted (ie test results are negative) when it is actually present
Positive: Assessment error in which pathology is reported when it is actually not present.
Degree to which two or more observers make the same ratings or measurements
Your mental age based on where you scored on intelligent test
Minnesota Multiphasic Personality Inventory (MMPI)
Developed in late 1930's. Empirically derived standardized personality test that provides scales for assessing such abnormal functioning as depression and paranoia. One of the mose widely used and heavily researched assessment instruments
Categorization system such as in DSM IV, employing several dimensions ore axes, each used for differentiating among the categories.
Classification and naming system for medical and psychological phenomena.
Degree to which an assessment instrument accurately predicts a persons future behavior
Changes in one persons behavior as a result of observing the behavior in another
Process of establishing specific norms and requirements for a measurement technique to ensure it is used consistently across measurement occasions. This includes instructions for administering the measure, evaluating its findings, and comparing these to data for large numbers of people.
Early standardized intelligence test designed to identify children who will experience academic difficulties by assessing their attention, perception, reasoning and comprehension
Wechsler scales of intelligence
IQ tests. 3 kinds: adult, children and preschool