Since 1980, the U.S. has seen an increase in the prevalence of reported anxiety disorders of more than 1,200 percent. Research over the past decade shows that feeling anxious is how the brain's emotion centers send signals to its thinking centers that something is amiss. "There is great evolutionary and survival value in anxiety, which makes it difficult to identify as an illness or pathology," said psychologist Frank Farley, a professor in Temple's Department of Education.