Deriving the Transdiagnostic Scales From the Personality Assessment Inventory and SPECTRA: Indices of...

Transdiagnostic models of psychopathology address many of the shortcomings common to categorical diagnostic systems. These empirically derived models conceptualize psychopathology as a few broad interrelated and hierarchically arranged dimensions, with an overarching general psychopathology dimension, the p-factor, at the apex. While transdiagnostic models are gaining prominence in mental health research, the lack of available tools has limited their clinical translation. The present study explored the potential of creating transdiagnostic scales from the joint factor structure of the Personality Assessment Inventory, Alternative Model of Personality Disorder trait scales (AMPD), and the clinical scales of the SPECTRA: Indices of Psychopathology (SPECTRA). Exploratory factor analysis in a clinical sample (n = 212) identified five factors corresponding to the Negative Affect/Internalizing, Detachment, Antagonism/Externalizing, Disinhibition/Externalizing, and Thought Disorder transdiagnostic dimensions. Goldberg's "Bass-Ackward" method supported a hierarchical structure. Five composite transdiagnostic scales were created by summing each factor's highest loading PAI and SPECTRA scales. A global psychopathology scale was created by summing the five composite scales. All the composite scales demonstrated adequate internal consistency. Correlations between the composite scales and the NEO Five-Factor Inventory-3 provide initial validity evidence for four composite and global scales. The composite thought disorder scale had no conceptually corresponding NEO domain. Clinical implications and study limitations are discussed.