Dysfunktionale Erwartungen bei Personen mit depressiver Symptomatik - Relevanz, Aufrechterhaltung und Mechanismen der Veränderung

Numerous studies have provided evidence for the crucial role of dysfunctional cognitions in major depression. However, recent research has suggested that dysfunctional expectations might be a particularly important subgroup of cognitions, because expectations refer to future events more specifically than other cognitions, and therefore expectations might be powerful predictors of future well-being. Thus, the purpose of this dissertation was to investigate the relevance of dysfunctional expectations in major depression. First, a novel questionnaire assessing depression-specific expectations with a high level of situational specificity was developed (Study 1). Using a convenience sample (N=175), the questionnaire has shown good psychometric properties. Subsequently, cross-sectional data analysis using a clinical sample (N=95) indicated that situation-specific dysfunctional expectations (SDEs) represent an important link between global cognitions and depressive symptoms as SDEs mediated the effects of global cognitions on depressive symptoms (Study 2). Further, using longitudinal data from both a clinical (N=52) and a healthy sample (N=47) provided indications that SDEs rather than global cognitions predict later depressive symptoms (Study 3). Since Studies 1-3 have shown that dysfunctional expectations impact depressive symptoms, Studies 4-6 examined to what degree expectations are changed through expectation-disconfirming experiences. In Study 4, a theoretical model was developed, arguing that dysfunctional expectations in major depression often persist despite disconfirming evidence, because disconfirming evidence is devaluated using cognitive immunization strategies. Subsequently, an experimental paradigm was developed in Study 5 to investigate expectation change using a student sample (N=102). Finally, Study 6 provided evidence for the hypothesis that people suffering from major depression (N=58), contrary to healthy individuals (N=59), tend to maintain their expectations despite expectation-disconfirming experiences. Moreover, another experiment (N=59) indicated that cognitive immunization is indeed a mechanism underlying expectation persistence in depression.