Sunday, April 29, 2012

Psychiatric diagnosis: pros and cons of prototypes - World Psychiatric Association

World Psychiatric Association / English

Psychiatric diagnosis: pros and cons of prototypes
vs. operational criteria


Mario Maj
President, World Psychiatric Association

The development of operational diagnostic criteria for
mental disorders in the 1970s was a response to serious concerns
about the reliability of psychiatric diagnosis. Initially
intended only for research purposes, the operational approach
was subsequently proposed also for ordinary clinical
practice by the DSM-III. That this approach increases the
reliability of psychiatric diagnosis in research settings is now
well documented. Much less clear, even in the US, is whether
the approach is commonly used by clinicians in ordinary
practice, thus really resulting in an increase of the reliability
of psychiatric diagnosis in clinical settings. It has been, for
instance, reported that several US clinicians have difficulties
to recall the DSM-IV criteria for major depressive disorder
and rarely use them in their practice (e.g., 2). Furthermore,
some of the DSM-IV cut-offs and time frames have been
found not to have a solid empirical basis (e.g., 3) and to
generate a high proportion of sub-threshold and “not otherwise
specified” cases (e.g., 4).
More in general, it has been maintained that a “prototype
matching” approach is more congruent with human (and
clinical) cognitive processes than a “defining features” approach
(e.g., 5). The spontaneous clinical process does not
involve checking in a given patient whether each of a series
of symptoms is present or not, and basing the diagnosis on
the number of symptoms which are present. It rather involves
checking whether the characteristics of the patient
match one of the templates of mental disorders that the clinician
has built up in his/her mind through his/her training
and clinical experience.
Moreover, some recent research focusing on various
classes of mental disorders (i.e., personality disorders, eating
disorders, anxiety disorders) suggests that a diagnostic system
based on refined prototypes may be as reliable as one
based on operational criteria, while being more user friendly
and having greater clinical utility (e.g., 6).

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