Anxiety disorder

The term anxiety disorder is a term for a number of psychiatric disorders. These disorders can be classified into two very broad groups:
Anxiety conditions include phobia, social anxiety disorder and generalized anxiety disorder. Other anxiety disorders include agoraphobia and panic disorder. Stress from life events, including past abuse, being intimidated or health worries, can trigger anxiety problems for many people. Symptoms include headache, spasms in the muscle, trembling, fatigue and exhaustion. There are various manners for treating anxiety disorders. These include medication and therapy. There is some recent research.
When people talk about feeling, they use the words anxiety and fear without making much of a difference. When professionals talk about them, there is a difference, though: Fear always has a cause, people are afraid of something or of something happening. So fear is the emotional response to an external threat. Anxiety is more general, the cause is either not known, or not controllable easily. 
Both fear and anxiety are normal reactions, to protect against a threat. Someone feeling fear or anxiety now and then does not have an anxiety disorder. Only when they occur so often that they impact people's lives do they become a disorder.