Distinguishing Between the Validity and Utility of Psychiatric Diagnoses

Abstract

It is important to distinguish between validity and utility in considering psychiatric diagnoses. Diagnostic categories defined by their syndromes should be regarded as valid only if they have been shown to be discrete entities with natural boundaries that separate them from other disorders. Although most diagnostic concepts have not been shown to be valid in this sense, many possess high utility by virtue of the information about outcome, treatment response, and etiology that they convey. They are therefore invaluable working concepts for clinicians.

Quality of life in children with OCD before and after treatment

“…However, there is little evidence that most mental disorders are separated by natural boundaries (Angold & Costello, 2009;Kendell & Jablensky, 2003). This is illustrated in a study by Fergusson and colleagues (2005) that explored the continuity of depressive symptoms from youth to adulthood.…”

Should cognitive impairment be included in the diagnostic criteria for schizophrenia?

“…The ability of a diagnostic refinement to improve the distinction between two entities and thus create an increased non-overlap between them is considered to be a crucial determinant for inclusion (14). Thus, the first question to be considered is whether adding the above definition of cognitive impairment to the criteria for schizophrenia will help define a "point of rarity" with other diagnostic entities, particularly affective disorders.…”

“…Even if the inclusion of a definition of "cognitive impairment" in the criteria for schizophrenia does not increase the point of rarity between schizophrenia and other psychotic disorders, it should be considered whether such a change would be able to "provide useful information not contained in the definition of the disorder that helps in decisions about management and treatment" (14). Psychiatrists rarely consider cognitive function in their evaluation of patients with schizophrenia.…”

Problem behaviours and symptom dimensions of psychiatric disorders in adults with intellectual disabilities: An exploratory and confirmatory factor analysis

“…The weak relationship between categorical diagnoses and clinical outcomes is recognised as an important limitation to the clinical utility of categorical diagnoses. However, categorical diagnoses make a useful contribution to communication with service users and between health professionals (Kendell & Jablensky, 2003), so dimensional models are best considered as complementary, rather than an alternative, to categorical diagnoses (Kotov et al, 2011). Using dimensional models alongside categorical diagnoses may provide more accurate information on prognosis, and facilitate clinical decision making about management.…”