The temporal stability of the bifactor model of comorbidity: An examination of moderated continuity pathways.

BACKGROUND: Structural models of psychopathology indicate that common mental disorder comorbidity reflects latent transdiagnostic factors. Multiple studies have replicated transdiagnostic internalizing (mood and anxiety disorders) and externalizing (substance use, antisociality-, and impulsivity-related disorders) factors; other studies support distress and fear sub-factors of internalizing. These factors show a high degree of temporal stability. Recently, a bifactor conceptualization of multivariate comorbidity has emerged, positing the existence of an orthogonal general psychopathology factor that saturates all diagnoses in addition to internalizing/distress/fear and externalizing, although no studies have examined the temporal stability of the factors in this competing model over time among adults.

METHOD: In a large, two-wave nationally representative sample (N=43,093), we investigated the structure of the bifactor model and examined all potential within- and between-factor stability pathways in a structural equation modeling framework.

RESULTS: In general, within-domain stability (e.g., Wave 1 general factor predicting Wave 2 general factor) was high, while between-domain pathways (e.g., Wave 1 general factor predicting the Wave 2 externalizing factor) did not differ significantly from zero. We then tested possible age and gender moderation of factor stability, finding that the stability for all factors, except fear, significantly differed across demographic sub-groups. However, these differences were not clinically meaningful.

CONCLUSIONS: Results indicated that bifactor model factors show varying degrees of temporal stability, with lowest comorbidity continuity over time reflecting distress stability. Findings are discussed with regard to recent evidence that the general factor may, to some extent, represent the negative emotionality captured by internalizing/distress in correlated two- and three-factor solutions.