Common cause vs dynamic mutualism: an empirical comparison of two theories of psychopathology in two large longitudinal cohorts
Mental disorders are highly prevalent, and among the leading causes of global disease burden. To respond in a timely and effective manner, a strong understanding of the structure of psychopathology and its development is critical. We compared the ability of two competing frameworks, the dynamic mutualism theory and the common cause theory, to explain the development of individual differences in psychopathology. We formalized these theories into statistical models, and applied them to two domains of psychopathology, at two different developmental periods, using two large developmental cohorts: the p factor (i.e. general psychopathology) from early to late adolescence (N = 1,482), and major depressive disorder in middle adulthood and old age (N = 6,443). The development of the p factor was better explained by a mutualistic account. In contrast, the evidence for the development of major depression was more ambiguous. Our results support a multicausal approach to understanding psychopathology and showcase the value of translating theories into testable statistical models for understanding developmental processes in clinical sciences.