Anxiety, on the other hand, is more general and complex. It is felt in anticipation of danger, and is associated with the ability to predict, prepare for, and adapt to change. Often, it lasts a long time, and its cause remains ill-defined. For example, someone uneasy about public speaking may experience a tightness in the stomach for days before a scheduled talk.
As long as there's a good reason for fear or anxiety, and it doesn't interfere with the ability to work, play, and socialize, it is not considered a problem. But when anxiety takes on a life of its own and begins to disrupt everyday activities, the situation is no longer normal. A genuine emotional disorder is now at work... and it's time to see a doctor.
Although it's uncommon, certain medical problems can mimic the symptoms of anxiety, or even produce it. The palpitations and shortness of breath caused by an irregular heartbeat can easily be mistaken for anxiety. A clot in the lung (pulmonary embolism) often causes unexplained feelings of anxiety. Neurological problems such as epilepsy and brain disorders can be responsible for symptoms of anxiety. So can anemia, diabetes, thyroid disease, and adrenal problems. In general, these symptoms will disappear when the underlying disease is brought under control, although the anxiety sometimes requires separate treatment.
By learning more about brain circuitry involved in fear and anxiety, scientists may be able to devise new and more specific treatments for anxiety disorders. For example, it someday may be possible to increase the influence of the thinking parts of the brain on the amygdala, thus placing the fear and anxiety response under conscious control.
Scientists are also conducting clinical trials to find the most effective ways of treating anxiety disorders. For example, one trial is examining how well medication and behavioral therapies work together and separately in the treatment of obsessive-compulsive disorder. Another trial is assessing the safety and efficacy of medication treatments for anxiety disorders in children and adolescents with co-occurring attention deficit hyperactivity disorder. For more information about clinical trials, for example the National Library of Medicine's clinical trials database.
Each anxiety disorder has its own distinct features, but they are all bound together by the common theme of excessive, irrational fear and dread.