Barnett and Gotlib (1988b) have suggested that a diathesis-stress model is an appropriate framework for conceptualizing the development of depression. In particular, the cognitive theory of depression developed by Beck (1967) hypothesized that dysfunctional self-schemata or a self-deprecating attributional style which develops from early life experiences may cause an individual to hold rigid and inappropriate beliefs or attitudes toward oneself and the world (Beck et al., 1979). These dysfunctional attitudes include the need for perfectionistic achievement and constant approval by others, and may place individuals at greater risk for depression under certain conditions. It is thought that through their interaction with stressful life events, dysfunctional attitudes may trigger the onset of the somatic, affective, and motivational symptoms of depression (Beck et al., 1979).
The most widely used measure of cognitive vulnerability to depression is the Dysfunctional Attitudes Scale (DAS; Weisman & Beck, 1978). Studies using the DAS (with such samples as college students and psychiatric patients) have reported that depressed subjects exhibit significantly more dysfunctional attitudes than nondepressed subjects (Barnett & Gotlib, 1988a; Penedo et al., 2001). However, when stressful life events are also investigated, the findings are inconsistent. Some studies have found that a significant interaction of dysfunctional attitudes with stressful life events is a good predictor of depressive symptoms (Wise & Barnes, 1986), whereas other studies have not supported this hypothesis (Barnett & Gotlib, 1988a, 1990). In their studies of the effects of stressful life events and social support on depressive symptoms in college students, Barnett and Gotlib (1988a, 1990) found that the interaction of dysfunctional attitudes with social support accounted for the severity of the depressive symptoms, but the interaction of dysfunctional attitudes with negative life events did not. Analysis of the former interaction suggested that subjects who had higher dysfunctional attitudes were more likely to report severe depressive symptoms when they perceived themselves to have lower levels of social support. Barnett and Gotlib's explanation was that depressed people maintain their self-esteem through dependent relationships with others. Low social support or the absence of social support for people with dysfunctional attitudes may threaten their self-worth, resulting in more severe depression.
The interplay of negative life events, dysfunctional attitudes, and social support in the development of depression has not yet been explained satisfactorily. In fact, there have been few studies addressing the interrelationships among these variables. Klocek, Oliver, and Ross (1997) investigated the role of dysfunctional attitudes, negative life events, and social support in the prediction of depressive dysphoria; specifically, they conducted a longitudinal study which measured dysfunctional attitudes at time 1, negative life events and social support at time 2, and dysphoria at time 3. Hierarchical multiple regression revealed no significant two-way interactions among the variables. In contrast, there was a significant three-way interaction among negative life events, dysfunctional attitudes, and social support. Klocek et al. further divided subjects into eight groups based on median splits on the three psychosocial predictor variables. Analysis of variance indicated that the combination of higher dysfuncti onal attitudes and a high number of negative life events predicted higher levels of depressive dysphoria regardless of the reported size of the social support network; moreover, lower levels of negative life events together with a larger social support network resulted in less severe symptoms of depressive dysphoria.
Although Klocek et al. (1997) have provided some information about the interaction between these variables, their work nevertheless does not especially elucidate the interplay of social support and dysfunctional attitudes. …