Anxiety Sensitivity Index (ASI) correlation to positron emission tomography (PET) scans of individuals coping with an anxiety-producing situation

In an attempt to identify neural correlates of the propensity to develop anxiety reactions, Positron Emission Tomography (PET) was used with two groups of healthy young participants (with significantly higher and lower ASI scores) in conjunction with repeated exposure to 8% CO2 inhalation. Hyperventilation is a key symptom in patients with acute anxiety or panic disorder. The Anxiety Sensitivity Index (ASI) has been shown to predict respiratory and subjective responses to an anxiety producing challenge (CO 2 inhalation) in healthy volunteers and patients with panic disorder. The outcome of this study is a correlation of the ASI to the self-reported and imaged results. Implication was determined using regional blood flow (rCBF) changes in correlation with ASI, temperament, and state and trait anxiety scores. Results indicate that there are significant differences in rCBF in the anterior cingulate between subjects with higher and lower ASI scores. In the low group there was a significant deactivation in the right anterior cingulate (z = -6.4) as well as a strong activation in the left anterior cingulate (z = 5.4). In the high ASI group there were similar activations in the right anterior cingulate (z = 6.4), however the deactivation in the left anterior cingulate was minimal and not significant. The cingulate has been linked to regulation of sad emotional information, and this may be the basis for using information from the ASI as a predictor of susceptibility to anxiety disorders and to better understand adaptive and maladaptive brain processes involved in the regulation of anxiety.