Extinctie, Vermijding en Generalisatie in het Ontstaan en de Behandeling van Angst

Individuals differ in their susceptibility to anxiety disorders and in their response to treatment: where some quickly develop symptoms after an anxiety-inducing experience, others remain unaffected, and while some benefit from treatment, others show less improvement or may relapse afterward. However, the mechanisms underlying these individual differences are still only partially understood. While laboratory models of fear acquisition have long been used to study anxiety, recent research suggests that alternative learning processes - such as fear extinction, avoidance, and generalization - may offer stronger insights into why some individuals are more resistant to developing anxious symptomatology and why some respond better to treatment compared to others. However, current research on these processes remains somewhat limited, and the existing studies typically examine one process independently instead of all in combination. To address this gap, the first part of the dissertation investigates to what extent laboratory-based measures of acquisition, extinction, avoidance, and generalization predict individual differences in anxiety development (Chapter 1) and treatment outcomes (Chapter 2). The prospective studies in Chapter 1 and 2 assess these processes both separately and in interaction to evaluate their potential as predictors of future anxiety symptoms. Chapter 3 moves beyond these processes by exploring intolerance of uncertainty as a potential predictor of treatment outcomes. The second part of this dissertation shifts to a potential clinical implication of the findings from Part 1. It explores the potential to improve exposure outcomes through a heightened focus on overcoming avoidance, specifically by increasing engagement with feared stimuli through the promotion of approach behavior. Chapter 4 introduces this theme, setting the stage for two studies that explore the efficacy and underlying mechanisms of this strategy. Chapter 5 evaluates the impact of approach behavior on fear extinction outcomes in a controlled laboratory setting, additionally exploring potential mechanisms: increased expectancy violation, altered stimulus valence, and altered action tendencies. Chapter 6 applies this strategy to an exposure protocol for spider-fearful individuals, assessing both short- and long-term effects on fear and avoidance while also exploring potential mechanisms, in this case including expectancy violation, stimulus valence, and self-efficacy. Finally, a general discussion synthesizes findings from the preceding chapters, highlighting their relevance for both anxiety research and clinical practice.