As noted previously, normal anxiety is actually beneficial. However, anxiety becomes a problem when it overstays its welcome (duration), and/or is of an intensity or frequency which begins to interfere with a person's functioning and overall well-being. These three factors- duration, intensity, and frequency- distinguish normal, adaptive anxiety from abnormal, pathological anxiety. As such, abnormal anxiety is different from normal anxiety because it is disproportionate to the situation that elicited the anxious response. When the intensity, duration, and/or frequency of anxiety become distressful and chronic, such that it interferes with a person's functioning, it is often referred to as pathological anxiety. Anxiety disorders represent variant forms of this pathological anxiety.
Therefore, the difference between normal anxiety and abnormal anxiety is this: anxiety is considered normal and adaptive when it serves to improve peoples' functioning or wellbeing. In contrast, abnormal anxiety is a chronic condition that impairs peoples' functioning and interferes with their well-being. This impairment causes them significant distress. There are specific symptoms that accompany each anxiety disorder. However, the main criteria used to distinguish normal anxiety from an anxiety disorder is that it results in significant distress, or impairs social, occupational, or other important areas of functioning (APA, 2013). This distinction is important. For instance, I may have a phobia about going to see the dentist. I may even have panic attacks prior to a dental visit. Nonetheless, I still go to see the dentist regularly and it does not create health problems or enormous distress for me. Therefore, I do not meet criteria for a phobia disorder. More information about the diagnosis and classification of anxiety disorders is provided in another section.
According to the National Institute of Mental Health (NIMH, 2008), approximately 40 million American adults (i.e., 18.1 %) have an anxiety disorder in a given year, with their first episode occurring before the age of 21.5. This prevalence rate is really quite astonishing: roughly one person in five will have experienced an anxiety disorder during that year. Interestingly, these estimates are not unique to the United States. Similar prevalence rates are reported for the global population. Moreover, evidence suggests that women tend to experience anxiety disorders more frequently than men do; approximately a 2:1 ratio (APA, 2013).
There are several reasons it is important to make this distinction between normal, adaptive anxiety, versus anxiety as a disorder. First, it would be incorrect to conclude someone is suffering from an anxiety disorder simply because they are experiencing some degree of anxiety. As explained above, anxiety as an emotion is a normal reaction to certain situations and even serves a useful purpose. Thus, it is neither necessary, nor beneficial, to attempt to rid ourselves of all anxiety.
Second, it is important for each of us to recognize that our own normal experiences of ordinary anxiety are qualitatively different from a person experiencing an anxiety disorder. Often, well-intentioned family and friends will offer advice to people attempting to recover from anxiety disorders. Unfortunately, these well-meaning friends and family cannot understand why the person-in-recovery reacts so negatively to their genuine efforts to help them "get over it." These sorts of techniques may be useful for coping with ordinary anxiety, but are not effective once anxiety has reached a pathological level. Indeed, without proper information about anxiety disorders, people-in-recovery and their loved ones may find themselves becoming increasingly frustrated with each other. This is why education for family and loved ones can be very beneficial.