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Editors: Tomb, David A.

Title: Psychiatry, 7th Edition

Copyright 2008 Lippincott Williams & Wilkins

> Table of Contents > Chapter 1 - Psychiatric Classification

Chapter 1

Psychiatric Classification

DSM-IVPsychiatric diagnosis has long been criticized as ambiguous and unreliable. Some diagnoses have been based on subjective, unverifiable, intrapsychic

phenomena, whereas others have been heterogeneously broad.

Modern diagnosis attempts to avoid these pitfalls through the use of the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR)

(1), which identifies each disorder by a unique specific collection of symptoms. (Note: throughout this text, the term DSM will be used to represent the most

recent edition, DSM-IV-TR.) It defines a limited number of identifiable (although possibly overlapping) psychiatric disorders and contains specific diagnostic

criteria for each diagnosis. One matches facts from a particular patient's history and clinical presentation with criteria from a likely diagnosis, and if an

adequate number are met (a polythetic diagnosis; not all the criteria are needed to make the diagnosis), that diagnosis should be made. Each disorder has a

unique set of these operationally defined diagnostic criteria. Multiple diagnoses are permitted, and each general group of disorders has one disorder, Not

Otherwise Specified (NOS), that allows placement of the (often many) patients who have unusual presentations. In addition, some disorders have subtypes,

which are mutually exclusive (e.g., paranoid schizophrenia) or specifiers that are not (may change with time; e.g., mild, moderate, and severe, or in full

remission) or both. Finally, it is okay to make a provisional (you are not sure) or a deferred (not enough information) diagnosis.

For example, a patient who (a) has been having delusions and auditory hallucinations that (b) have impaired social relations and functioning at work (c) for at

least 6 months and who is without evidence of (d) a general medical condition or (e) prominent symptoms of a major mood disorder must be given the

diagnosis of schizophrenia. If the patient also has (f) a flat, inappropriate, or

silly affect and (g) disorganized speech and behavior, an additional diagnosis of disorganized subtype should be made.

DSM-IV has improved diagnostic reliability (the likelihood that different professionals would make the same diagnosis on the same patient) but has had only a

modest impact on validity (the certainty that the diagnoses identify unique meaningful conditions). It may well be that DSM-IV has broken psychiatric

conditions into too many pieces and that each piece does not represent a valid condition (2,3). A common criticism is that the criteria allow too many minor

human behaviors to be classed as disorders (false positives), a problem partially corrected by insisting that each set of behaviors has serious clinical

significance (4).

Note also that DSM-IV makes no assumptions about what causes these disorders (it just describes and categorizes them), and in most cases, the etiology is

unknown. Although DSM-IV holds up well across cultures, its use in those settings requires special care in the interpretation of symptoms. DSM-IV is far from

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perfect (5) and thus allows the use of clinical judgment as well as strict application of the criteria in making a final diagnosis. Remember, ultimately it is the

patient and the patient's narrative/life story that we are treating, not the diagnosis.

MULTIAXIAL CLASSIFICATIONIn addition to operationally defined criteria, DSM-IV also uses a multiaxial system of classification to capture other important information. A patient is not fully

classified until coded on each of five axes (although only the first three axes are needed for an official diagnosis):

Axis I: The clinical disorder(s) described earlier.

Axis II: Personality disorders or mental retardation (none may be present) or both.

Axis III: Physical disorders relevant to the mental disorder.

Axis IV: A listing of psychosocial and environmental problems, usually but not always during the preceding year, such as unemployment, divorce, financial

problems, victim of child neglect, and so on.

Axis V: The Global Assessment of Functioning Scale (GAF) (DSM, p. 34), which is a measure, typically, of current general functioning but at times of the

highest functioning over the preceding year (scale range is 1 to 100) and which is used in treatment planning and predicting outcome.

REFERENCES

1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision. Washington, DC: American Psychiatric

Association, 2000.

2. Phillips KA, First MB, Pincus HA. Advancing DSM. Washington, DC. American Psychiatric Association, 2003.

3. Sullivan PF, Kendler KS. Typology of common psychiatric syndromes. Br J Psychiatry 1998;173:312-319.

4. Spitzer RL, Wakefield JC. DSM-IV diagnostic criterion for clinical significance: does it help solve the false positives problem? Am J Psychiatry

1999;156:1856-1864.

5. Tucker GJ. Putting DSM-IV in perspective. Am J Psychiatry 1998;155:159-161.

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