Mnemonic Discrimination and Psychopathology: An Investigation of Clinical Correlates, Potential Mechanisms, and Interventions

Abstract

Cognitive biases or errors whereby safe and threatening contexts are conflated may play an important role in the development of clinical anxiety. In this vein, the present projects are designed to enhance a mechanism-focused conceptualization of anxiety by exploring the process of mnemonic discrimination. This feature of episodic memory reflects the adaptive integration of old and new experiences and allows similar entities to be differentiated. When impaired, poor mnemonic discrimination could cause individuals to overgeneralize their construals of threat. However, there is little empirical work testing insufficient memory resolution, or poor mnemonic discrimination, as a contributory mechanism of anxiety or related emotional disorders. The present projects provide an initial examination of whether mnemonic discrimination is a promising target for anxiety research. This dissertation addresses three foundational questions: (1) Is weaker mnemonic discrimination associated with symptoms of anxiety? (2) Is overgeneralization of fear a plausible mediating mechanism connecting poor mnemonic discrimination to clinical anxiety? (3) Is mnemonic discrimination sensitive to acute intervention, such that manipulating certain variables could affect improvement or impairment in performance? In Paper 1, I assessed mnemonic discrimination in adults ranging widely in anxiety severity under three conditions: neutral, psychological threat (social evaluative stressor), and physical threat (aversive sounds). Contrary to extant theories of mnemonic discrimination and anxiety disorders, there was no relationship between mnemonic discrimination in neutral conditions, as typically assessed, and anxiety. However, poor mnemonic discrimination performance following the psychological stressor, but not the physical stressor, was associated with more severe symptoms of anxiety. In Paper 2, consistent with hypotheses, poor mnemonic discrimination performance was related to broader generalization of subjective fear responses. Although broader generalization gradients were also associated with clinical levels of anxiety, the absence of a direct effect of mnemonic discrimination on anxiety precluded a mediation analysis. In Paper 3, participants who engage in more regular aerobic exercise demonstrated better mnemonic discrimination than participants who were less active or sedentary. Acute exercise in the laboratory further widened this gap. Notably, this augmentation effect did not hold for participants experiencing moderate to severe mood symptoms. Results suggest that poor mnemonic discrimination could increase vulnerability for overgeneralization of fear and consequently the development of anxiety disorders. Encouragingly, results also suggest that certain interventions, such as aerobic exercise, may enhance performance or at least protect against its decline. Findings also highlight limitations and hypothesized boundary conditions to consider for future research. For example, difficulties with mnemonic discrimination under states of psychological distress or for disorder-relevant content may be more fruitful targets than basic or domain-general mnemonic discrimination abilities. Furthermore, the success of targeted interventions may vary widely depending on clinical status or illness duration. Taken together, this research justifies additional exploration of mnemonic discrimination, its role in anxious psychopathology, and its malleability, but also encourages caution that these connections may not be as clear or direct as previously proposed.