Expectation of Unpleasant Events in Anxiety Disorders
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.
|Official Title:||Predictability and Aversive Expectancies in Anxiety and Depressive Disorders|
|Study Start Date:||February 2003|
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 anxious individuals.
A second aim is to examine processes that may promote the development of contextual fear. Classical aversive-conditioning is an ideal technique to explore cognitive, attentional, and emotional processes underlying the development of aversive expectations to explicit and contextual cues. We will attempt to relate conditioned performance to measures of 1) autonomic reactivity (orienting response and heart-rate variability) and 2) attentional bias. Substantial evidence suggests that autonomic reactivity has broad implication for cognitive and affective regulation and that attentional biases may imply a role in generating and/or maintaining maladaptive levels of anxiety.
A third aim is to use socially-relevant stimuli to examine fear and anxiety in social anxiety disorders. These include a speech stressor given in a virtual reality environment and using faces as conditioned stimuli and social words in a classical conditioning experiment.
Finally, given the high comorbidity between anxiety and depression, a last aim is to examine the role fo depression on these measures of fear and anxiety.
Please refer to this study by its ClinicalTrials.gov identifier: NCT00055224
|Contact: Marilla Geraci, R.N.||(301) email@example.com|
|Contact: Christian Grillon, Ph.D.||(301) firstname.lastname@example.org|
|United States, Maryland|
|National Institutes of Health Clinical Center, 9000 Rockville Pike||Recruiting|
|Bethesda, Maryland, United States, 20892|
|Contact: For more information at the NIH Clinical Center contact Patient Recruitment and Public Liaison Office (PRPL) 800-411-1222 ext TTY8664111010 email@example.com|
|Principal Investigator:||Christian Grillon, Ph.D.||National Institute of Mental Health (NIMH)|