 This could perhaps be due to the increased difficulty in discriminating between anxiety and depression in older adults due to "de-differentiation" of the symptoms of anxiety with the aging process, as hypothesized by Krasucki et al.Many questions of the Beck Anxiety Inventory include physiological symptoms, such as palpitations, indigestion, and trouble breathing.Because of this, it has been shown to elevate anxiety measures in those with physical illnesses like postural orthostatic tachycardia syndrome, when the Anxiety Sensitivity Index did not.