Effects of Arousal and Stress in Anxiety

This study has several parts. One part will examine the influence of factors such as personality and past experience on reactions to unpleasant stimuli. Others will examine the effect of personality and emotional and attentional states on learning and memory.

When confronted with fearful or unpleasant events, people can develop fear of specific cues that were associated with these events as well as to the environmental context in which the events occurred via a process called classical conditioning. Classical conditioning has been used to model anxiety disorders, but the relationship between stress and anxiety and conditioned responses remains unclear. This study will examine the relationship between cued conditioning and context conditioning . This study will also explore the acquisition and retention of different types of motor, emotional, and cognitive associative processes during various tasks that range from mildly arousing to stressful.

Objective: Fear and anxiety are adaptive responses to different types of threats. Fear is a short-duration response evoked by explicit threat cues and anxiety a more sustained state of apprehension evoked by unpredictable threat. This protocol studied fear using Pavlovian fear conditioning in two studies. Studies 1 and 3. Study 2 focused on anxiety. Studies 1 and 3 will be discontinued to focus uniquely on the study of anxiety. Specifically, we will examine the interactions between anxiety induced experimentally using verbal threat and cognitive processes. We will seek to 1) characterize the effect of anxiety on key cognitive processes including working memory and attention control and 2) examine the extent to which performance of cognitive tasks distract from anxiety.

Study population: This more-than-minimal-risk protocol will test medically and psychiatrically healthy volunteers aged 18-50. Pregnant or nursing women will be excluded.

Method: Fear and anxiety will be measured using the startle reflex to brief and loud sounds. Fear conditioning will be assessed using shock as unconditioned stimulus. Cognitive performance will be examined during periods of unpredictable shock anticipation.

Outcome measures: The study will include cognitive performance and measure of aversive states, primarily the startle reflex.

Eligibility Criteria:
* INCLUSION CRITERIA:
* Males and females
* Age 18-50

EXCLUSION CRITERIA:

* Pregnancy
* Any current ongoing medical illness
* Current Axis I disorders
* Past significant psychiatric disorders (e.g., psychotic disorders) according to Diagnostic and Statistical Manual (DSM)-IV
* Current alcohol or substance abuse according to DSM-IV criteria
* History of alcohol or substance dependence based on DSM-IV criteria within 6 months prior to screening
* Current psychotropic medication use
* Current or past organic central nervous system disorders, including but not limited to seizure disorder or neurological symptoms of the wrist and arms (e.g., carpal tunnel syndrome). The latter exclusion is for shock studies only.
* Positive urine toxicology screen
* Employees of National Institute of Mental Health (NIMH) or an immediate family member of a NIMH employee.