Anxiety is a human condition that affects many people. It affects how we feel, how we behave and has very real physical symptoms. It feels a bit like fear but whereas we know what we are frightened of, we often don't know what we are anxious about. Mild anxiety is vague and unsettling, while severe anxiety can be extremely debilitating.
A lack of faith can be a primary cause of anxiety (see: Atheism and cowardice). In addition, a false perception of reality, an exaggerated dependence on things outside of one's control, and a lack of meaningful purpose can be contributing causes.
Causes of Anxiety
A number of factors including stress appear to contribute to the development of anxiety.
Anxiety is often triggered by stress in our lives. Some of us are more vulnerable to anxiety than others, but even those who become anxious easily can learn to manage it well. We can also make ourselves anxious with negative self-talk - a habit of always telling ourselves the worst will happen. 
How to Recognize Anxiety
Some of the following physical symptoms could be present:
- Excessive worry and tension
- Tense muscles
- Churning stomach
- Heart palpitations
- Numbness or "pins and needles" in arms, hands or legs
Symptoms of anxiety could be confused with physical illness; for example: becoming worried that you might be suffering a heart attack or stroke could increases anxiety. We all become anxious from time to time. It becomes a problem when it interferes with life in the absence of real threat, or goes on too long after the danger has past. Avoiding situations that make you anxious might help you feel better in the short term. The trouble is when the anxiety keeps returning, and has a habit of spreading to other situations. This could lead to you avoiding things like shops, crowded places, lectures or tutorials. So although avoidance makes you feel better, that relief is only temporary and sometimes you may worry about what will happen next time. Every time you avoid something it could be harder next time you try to face it. Gradually you could want to avoid more and more things. Ibidem
Relaxation techniques and regular exercise could help in the treatment of anxiety.