Psychosis within dimensional and categorical models of mental illness

Abstract

There has been recent interest in dimensional and super-ordinate factor models of psychopathology. While early studies modelled psychopathology in terms of two dimensions representing “Internalising” and “Externalising” behaviours, more recent studies have begun to identify a distinct “Psychosis” dimension. This study estimated a global dimensional model of psychopathology that included all three dimensions. A categorical model was also used to explain heterogeneity across the dimensions. Using data from the National Comorbidity Survey, 11 Axis I diagnoses, conduct disorder and three indicators of psychosis were used in exploratory and confirmatory factor analyses which identified three correlated dimensions: Internalising, Externalising and Psychosis. Latent profile analysis, based on the factor scores from these dimensions, identified five homogeneous groups that differed both qualitatively and quantitatively. The benefits of person-centred modelling of the hierarchical dimensions of psychopathology are discussed.

Keywords:

• psychopathology
• psychosis
• internalising
• externalising
• dimension