Part of our research investigates the links between romantic relationships and psychopathology (i.e., mental illness). Research consistently shows that intimate romantic relationships, particularly marriage, play a vital contextual role in the etiology, development, and course of psychopathology. Both cross-sectional and longitudinal research demonstrates a link between marital distress and various forms of mental illness, including depression, anxiety, and alcoholism. The goal of research in our lab is to explicate the bidirectional nature of the transactions between romantic relationship functioning and psychopathology for different forms of disorders. For instance, we found that the association between specific mental disorders and marital distress can be explained by higher-order spectra of internalizing and externalizing pathology (South, Krueger, & Iacono, 2011). Further, the associations between INT/EXT and marital distress are in turn mediated by communication patterns between spouses (Jarnecke, Reilly, & South, 2016).
In other work, we are interested in examining the relationship between romantic relationships and personality. There has been a long history of research looking for the personality roots of marital dysfunction. Most of this research has centered on more normative personality traits, like neuroticism. In our research, we found that personality disorder symptoms were related to low levels of marital satisfaction, higher levels of verbal conflict, and greater likelihood of physical violence (South et al., 2008). One reason that PD symptoms might be associated with global perceptions of marital dissatisfaction is because people with higher levels of PD symptoms tend to display negative behaviors with their spouse on a daily basis (South, 2014)
Finally, the third area of research in the lab investigates links between personality and psychopathology. Personality and psychopathology are inevitably linked, although the specific mechanisms and models for how they may influence each other are still under theoretical and empirical debate. The model receiving perhaps the greatest amount of empirical support to explain the personality-psychopathology link is the spectrum model, which proposes that personality is correlated with various forms of psychopathology, which are in turn correlated with each other, because they are all manifestations of a higher-order spectrum. The personality trait of negative emotionality (or neuroticism) is easily added to the internalizing spectrum (South & Krueger, 2008). Dr. South is a member of the HiTOP Consortium (https://renaissance.stonybrookmedicine.edu/HITOP), a group of researchers who investigate dimensional ways of conceptualizing and categorizing mental illness using structural models of psychopathology.