The relevance of recent developments in classical conditioning to understanding the etiology and maintenance of anxiety disorders

Abstract

Current etiological models of anxiety disorders emphasize both internal diatheses, or risk factors, and external stressors as important in the development and maintenance of clinical anxiety. Although considerable evidence suggests personality, genetic, and environmental variables are important to these diathesis–stress interactions, this general approach could be greatly enriched by incorporating recent developments in experimental research on fear and anxiety learning. In this article, we attempt to integrate the experimental literature on fear/anxiety learning and the psychopathology literature on clinical anxiety, identify areas of inconsistency, and recommend directions for future research. First, we provide an overview of contemporary models of anxiety disorders involving fear/anxiety learning. Next, we review the literature on individual differences in associative learning among anxious and non-anxious individuals. We also examine additional possible sources of individual differences in the learning of both fear and anxiety, and indicate where possible parallels may be drawn. Finally, we discuss recent developments in basic experimental research on fear conditioning and anxiety, with particular attention to research on contextual learning, and indicate the relevance of these findings to anxiety disorders.

Introduction

Current etiological models of many mental disorders emphasize the importance of regarding psychopathology as the product of both internal diatheses that confer vulnerability and external (or internal) stressors that further increase the likelihood of developing particular disorders. This conceptualization recognizes the need for understanding individual differences among people that serve as vulnerability factors (such as dispositional traits, or early experiential differences), as well as a variety of environmental stressors that people are exposed to (such as stressful life events or perturbations of the neurochemical environment), and any potential interactions between the two. In the area of clinical anxiety, considerable research is accumulating to suggest certain personality, genetic, and early learning experiences as important diatheses. More proximal stressors often interact with these diatheses and culminate in the onset of a certain disorder. For instance, personality traits such as high trait anxiety or behavioral inhibition appear to be significant diatheses for a variety of anxiety disorders, and early aversive learning experiences have also been found to be important risk factors for the development of these disorders. More proximal adverse circumstances such as exposure to unpredictable and uncontrollable stress, or more discrete conditioning experiences, have been found to serve as stressors in this diathesis–stress framework.

Somewhat less attention, however, has been focused on the mechanisms of the putative diathesis–stress interactions central in the development of the anxiety disorders. Experimental research on fear learning in animals and humans, although largely a distinct research tradition from psychopathology and individual differences research, is highly relevant for understanding such mechanisms. Individual differences in the ability to learn about various aspects of the environment, combined with actual environmental differences provide parsimonious explanations for how diathesis–stress models may operate with the anxiety disorders. Unfortunately, the gap between the rich experimental literature on fear learning and the growing literature on individual differences as vulnerability factors has prevented an appreciation of these areas as complementary approaches. In this article, we attempt to integrate these two traditions and identify possible areas of inconsistency. We also recommend future directions for research to further explore this diathesis–stress perspective on anxiety disorders.