Genetics: Furthermore, as noted later in this section of the application, investigators have identified abnormalities in functioning of key structures (e.g., amygdala and insula) within the brain's anxiety circuitry in anxiety-prone subjects and there is evidence that certain genes (e.g., SLC6A4) influence the extent of activation in these regions. The focus of this project is to determine to what extent variation in CRF system genes (i.e., CRF, CRF-R1, CRF-R2, UCN, UCN2, UCN3) is associated with anxiety disorders.