Anxiety is a common feeling. It's your brain's way of coping with stress and warning you about impending danger. Everyone experiences anxiety from time to time. When faced with a problem at work, before taking a test, or before making a major decision, you may be concerned. Anxiety is normal on occasion. However, anxiety disorders are distinct. They're a collection of mental illnesses that cause uncontrollable anxiety and fear. Excessive anxiety may cause you to avoid work, school, family gatherings, and other social situations that may exacerbate or trigger your symptoms. Many people with anxiety disorders can manage their feelings with treatment.