The demands of comorbidity: Implications for the explanation and classification of mental disorder

A central goal of psychiatric classification is to assist in the assessment and treatment of those who experience mental disorder. This challenge takes on greater significance in complex cases, especially given the high prevalence of psychiatric comorbidity. High rates of comorbidity also challenge the validity of current psychiatric nosology. Etiological classification has been promoted as an alternative to improve the state of psychiatric diagnosis. However, comorbidity makes specific conceptual, explanatory and methodological demands of any such classification strategy. In this thesis, a demand for coherent and integrative explanation of comorbidity acts as a standard by which to assess the strength of different causal models of mental disorder and their resultant concepts. Integrative pluralism is presented as an epistemological framework well-suited to the complexity of this scientific challenge.