The purpose of this research is to refine and extend our understanding of how depressive vulnerability factors, such as dependency and self-criticism (Blatt et al., 1976), contribute to negative moods and influence the quality of interpersonal relationships. The main objective of this line of research is to validate an expanded vulnerability model, which examines the effects of vulnerability factors more broadly. The focus of this line of research is on the proximal effects of vulnerability factors on mood, behaviour and social cognition, all of which have a role in the onset, maintenance or amelioration of mood disturbance and interpersonal difficulties. Most studies on depressive vulnerability factors have focused on the direct relation between vulnerability factors and mood, rather than on the indirect effects that vulnerability factors may have on interpersonal functioning which in turn may influence mood. Research on vulnerability factors has examined the relation between vulnerability factors and information processing variables (e.g., Stroop word naming latencies). Only a small number of studies have examined the impact of vulnerability factors on interpersonal behaviour.
Studies I have completed to data have examined how dependency and self-criticism moderate (a) the cognitive representation of events that constitute a threat to self-worth or interpersonal relatedness, (b) the interpersonal responses to such events (whether individual adopt strategies that ameliorate or aggravate the quality of interpersonal relations), (c) memory processes for the recall of events that can be characterised as a threat to self-worth or interpersonal relatedness, as well as sustained mood disturbance (Santor & Patterson, 1999; Patterson & Santor, 1999), and (d) the extent to which depressive vulnerability factors are related to sustained, subthreshold mood disturbances in nonclinical populations. Other related work has examined the nature of dependency and self-criticism (Santor, Zuroff, Mongrain, & Fielding, 1998) and the relation between vulnerability factors and clinical depression (Santor, Bagby, & Joffe, 1998). In general, these studies have shown that dependency and self-criticism are associated with different behaviour responses to events that threaten self-worth or interpersonal relatedness, different cognitive representations of negative interpersonal events, as well as sustained mood disturbances. More recently, I have focused on the importance of psychological needs, and the extent to which psychological needs may mediate the relationship between vulnerability factors, negative life events and depressive symptoms. One theoretical papers (Santor, 2003) and one empirical paper (Kopala-Sibley & Santor, 2009) have been published examining this new approach and two more are under revision.
Traditionally, cognitive and interpersonal models of depression have been viewed as competing or alternative explanations, rather than as components of an integrated model. Numerous studies have been cited to either support or repudiate the causal relation between depression and vulnerability factors, and reviews criticizing both positions have appeared. Although theoretical advances have been made in recent years describing ways in which cognitive and interpersonal processes may be integrated, both cognitive and interpersonal theories can be criticized for ignoring the subtlety of the cognitive and interpersonal deficits individuals demonstrate and the manner in which cognitive and interpersonal processes interact. Cognitive vulnerability models need to consider how disruptive interpersonal events may activate depressive vulnerabilities like dependency and self-criticism and contribute to dysfunctional interpersonal processes, just as interpersonal models need to consider how depressive vulnerability factors may moderate the effects of disruptive interpersonal events, such as a disagreement from a partner.
Progress in understanding the impact of vulnerability factors on distal outcomes such as a mood disorder depends on gaining a better understanding of the vulnerability factors themselves and the proximal effects of vulnerability factors on behaviour, social cognition, and mood. Many of the studies conducted to date have used experimental methods, wherein interpersonal situations are manipulated (e.g., one member of a couple is told they have outperformed another) in order to investigate the impact of threats to self-worth or interpersonal relatedness on interpersonal behaviour and the extent to which behaviour is moderated by dependency and self-criticism. Experimental methods are crucial to understanding how vulnerability factors and interpersonal events contribute independently to disruptive interpersonal environments that have been associated with depressive processes.