Problematic or Proper?

Scotti and Morris  (2000) identify several problems with classification:

• Labels stick.
• The recent addition of everyday problems (e.g., caffeine-induced sleep disorder), might make diagnoses less meaningful.
• DSM/ICD diagnoses are Eurocentric and do not take ethnicity or culture into account.
• Their reliability and validity are constantly questioned.

• reliability
• internal consistency
• specificity
• external validity
• utility
• Has DSM evolved into a proper classification system?
• Reliability is function of the method used.  For example, structured interviews lead to more reliable diagnosis.  DSM has improved reliability with DSM-III and DSM-IV.
• Internal consistency varies across diagnoses.  For some, the client must meet only a fraction of the criteria to receive a diagnosis.
• Clearly, specificity has increased in DSM-III and DSM-IV with the addition of explicit criteria.
• External validity seems related to internal consistency.  Some diagnoses are useful summary variables while others offer little information about the individual.
• Utility varies by clinician but DSM-IV has taken steps to improve it.

    Although DSM may seem imperfect, remember that Linneaus’ taxonomy preceded Darwin’s theory of evolution by nearly a century.  Psychiatric classification may just be waiting for its Darwin to appear.

Two quotations from Frances and Egger (1999) summarize the past and current state of psychiatric classification:

In the present state of our knowledge, no classification of insanity can be erected upon a pathological basis for the simple reason that, with but slight exceptions, the pathology of the disease is unknown… we are forced to fall back on the symptomology of the disease.                                                                                                                                             

                                                                                                                                           Pliny Earle
                                                                                                                             Contemporary of Kraepelin                                                                                                                                                                                   

Science strives for simplicity of explanation… We are at the epicycle stage of psychiatry where astronomy was before Copernicus and biology before Darwin.                                                                                                         

                                                                                                                                Frances and Egger, 1999