Stress and anxiety are ubiquitous in life. Although they often are conceptualized as negative emotions, centuries of thought from diverse fields have highlighted their importance to creativity, motivation, and survival (Barlow, 2002). According to Tsigos, Kyrou, Kassi, and Chrousos (2000), stress is a state of threatened homeostasis caused by physical or emotional stressors, whether real or imagined, that results in a complex repertoire of physiological and behavioral responses to maintain or reestablish equilibrium. In the short term, a robust physiological stress response may be advantageous to appropriately respond and adapt to threatening situations or circumstances that pose imminent danger. However, persistent, unrelenting, or excessive activation of stress response systems-including the autonomic nervous system (ANS) and the hypothalamicpituitary-adrenocortical axis-may result in changes to the underlying neural circuitry that subserves normal, healthy functioning and may increase susceptibility to a number of physical and mental health conditions, including anxiety disorders.Anxiety is an emotion characterized by feelings of tension, heightened vigilance, excessive and inappropriate worrying, and physical symptoms of arousal, such as increased muscular tension, tachycardia, dyspnea, or gastrointestinal distress (Stein & Craske, 2017). Other symptoms of anxiety include restlessness, fatigue, difficulty concentrating, irritability, and sleep disturbances. When these symptoms are persistent, excessive or disproportionate to the demands of a situation, and interfere with normal day-to-day functioning, they constitute an anxiety disorder. Anxiety disorders result in significant distress, are frequently comorbid with mood and substance use disorders, and are associated with an increased risk of suicide (Bentley et al., 2016). Importantly, stress and anxiety disorders are associated with a variety of physical illnesses, including gastrointestinal disorders (Rieder, Wisniewski, Alderman, & Campbell, 2017), cardiovascular disease (Tully & Cosh, 2013), and all-cause mortality (Watkins et al., 2013). Together, the anxiety and stress-related disorders are among the most prevalent psychiatric conditions in the United States, annually affecting more than 20% (more than 40 million) of American adults (National Institute of Mental Health [NIMH], 2016).The lifetime prevalence of any anxiety disorder is approximately 30%, suggesting that one in every three individuals will suffer from an anxiety disorder in his or her lifetime. Many seemingly healthy individuals also suffer from high levels of daily life stress and subsyndromal anxiety symptoms. The World Health Organization (Murray & Lopez, 1996) Global Burden of Disease survey estimated that mental disease, including stress-related psychopathology, will be the second leading cause of disabilities by the year 2020. Although it is impossible to measure the true estimates of prevalence and costs attributable to chronic stress and anxiety, clinical anxiety disorders