Feeling tense, worried, or having "butterflies in your stomach" is one experience we are all familiar with. While it is not a particularly pleasant experience, normal anxiety serves an important function in our history as a species by helping to alert us to impending dangers. Anxiety is what would help trigger the "fight or flight" response in our ancestors when they encountered a tiger or grizzly bear, thus preserving our species.
These days, a little anxiety can still serve an adaptive role. For example, we might feel nervous the night before a public speaking event. In this case, anxiety would encourage us to rehearse our speech a few more times. In so doing, we improve the likelihood of a successful event the following day! Anxiety, however, is a combined physiological and psychological phenomenon and exists on a continuum. The difference between run-of-the-mill worries and an "anxiety disorder" is the degree to which that experience affects your ability to function.
Let's return to the example of the public speaking engagement. If your level of anxiety is too high, not only will you have a difficult time falling asleep the night before the speech, the anxiety itself could impair your attention and memory, thereby adversely affecting your performance the next day.
So, why does this happen?
In our brains, there are complex networks of nerves that are all interconnected. These different groups of nerve networks are responsible for regulating our mood, memory, attention, anxiety, and even pleasure. Our brains are constantly interfacing with information coming in from the environment around us, through what we see, hear, smell, taste and touch.
When this information is particularly stimulating to our anxiety nerve networks, we start to experience physiological changes such as dry mouth, sweaty palms, racing heart, shakiness, and upset stomach. This is an experience most people can relate to, and it often passes quickly. However, in about 18 percent of the population, this anxiety experience does not pass quickly, and can fill people with fear and uncertainty, significantly impairing their ability to work and play. This is usually the case among people who suffer from anxiety disorders, which can last at least six months and worsen if they are not treated.
A variety of anxiety disorders exist, including: generalized anxiety disorder (constant worrying), panic disorder (which involves "panic attacks"), social phobia, specific phobia, post-traumatic stress disorder, and obsessive-compulsive disorder. While each anxiety disorder manifests itself through different symptoms, what they share is a common excessive fear and impaired ability to function.
The good news is that there are effective therapies for anxiety disorders and a good place to start would be speaking with your doctor if you are concerned about any of the above symptoms. Diet, exercise, deep breathing, yoga, and meditation can always help with day-to-day worries and general anxiety. It is important to know, however, that sometimes medications, specific types of psychotherapy, or both, might be needed because lifestyle changes often cannot treat severe anxiety disorders alone.