Expectation of Unpleasant Events in Anxiety Disorders

    Not Recruiting
  • End date
    Jul 1, 2023
  • participants needed
  • sponsor
    National Institute of Mental Health (NIMH)
Updated on 8 August 2022
panic disorder
specific phobia
mood disorder
Accepts healthy volunteers


Fear and anxiety are normal responses to a threat. However, anxiety is considered abnormal when the response to the threat is excessive or inappropriate. This study will examine changes in the body and brain that occur during unpleasant learning experiences in healthy volunteers with high, moderate, and low levels of anxiety.

A high degree of generalized anxiety is a component of many anxiety disorders and is regarded as a marker of vulnerability for these disorders. People with anxiety disorders and individuals with high degrees of anxiety have inappropriate expectations of unpleasant events. This study will investigate the development of expecting unpleasant events in healthy volunteers with varying degrees of anxiety using aversive conditioning models. A later phase of the study will enroll participants with anxiety disorders and compare their responses to those of healthy volunteers.

Patients who meet criteria for an anxiety disorder, and healthy volunteers who have no history of psychiatric or major medical illness will be enrolled in this study. Volunteers will come to the NIH Clinical Center three times for outpatient testing.


High-generalized anxiety is a concomitant of many anxiety disorders and is often regarded as a vulnerability marker for these disorders. One characteristic of patients with anxiety disorders and high trait-anxious individuals is inappropriate expectancies of aversive events. The overall aim of the present protocol is to investigate mechanisms that may promote the development of these aversive expectancies using expectancy-based, associative-learning models.

During aversive conditioning in which a phasic explicit-cue (e.g., a light) is repeatedly associated with an aversive unconditioned-stimulus (e.g., a shock), the organism develops fear to the explicit cue as well as to the environmental context in which the experiment took place. We have obtained preliminary evidence suggesting that contextual fear represents aspects of aversive states that are central to anxiety disorders. In this protocol, we seek further evidence for the relevance of contextual fear to mood anxiety disorders.

One important determinant of contextual fear in both humans and animals is predictability: contextual fear increases when aversive events (e.g., electric shock) are unpredictable, as opposed to when they are predictable. The present protocol will examine the role of predictability of aversive states and of conditioning on threat appraisal in individuals with mood and anxiety disorders.

A second aim is to examine the interaction between experimentally-induced anxiety and cognitive processes, more specifically working memory, in mood and anxiety disorders.

Condition Anxiety Disorders
Treatment Acoustic startle, Electric Shock
Clinical Study IdentifierNCT00055224
SponsorNational Institute of Mental Health (NIMH)
Last Modified on8 August 2022

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