Am J Psychiatry 1993; 150:197-206
Copyright © 1993 by American Psychiatric Association
Diagnostic decision making in psychiatry
DA Zarin and F Earls
Developmental Epidemiology Research Unit, Judge Baker Children's Center, Boston.
The purpose of this article is to examine the consequences of and possible
responses to uncertainty in psychiatric diagnosis. Uncertainty is
inevitable because of the overlap in characteristics, or test results,
between populations with and without a psychiatric disorder. As a result,
there is never one correct method of identifying cases and noncases (i.e.,
case definition). In this paper principles of decision analysis and
clinical epidemiology are used to develop a framework for thinking about
the consequences of different diagnostic schema and for choosing among
them. The framework illustrated here involves choosing an external
validator, choosing a separator, and choosing a cutoff. This framework is
applied to the problems facing three hypothetical researchers, and the
consequences for their research of different diagnostic choices are
explored. It is demonstrated how the relevance of research to clinicians
and policy makers rests on the choice of the case definition process. The
prevalent use of structured psychiatric interviews has not been accompanied
by adequate attention to the problem of determining a diagnosis once the
information is obtained. It is argued that more attention must be given to
this process if we are to make optimal use of available resources for
research and treatment.
