Anxiety is a feeling of nervousness, worry or fear that can be acute or chronic. There are numerous reasons behind anxiety such as stress from work, bullying, use of drugs, etc. Anxiety does not usually happen at a fixed age but can start at a young age around 6. This type of anxiety is common and bullying, stress from school, etc. can be the reason behind such anxiety. 

The anxiety that occurs in teens and adults is extremely common. Stress from work, financial stress, stress fr personal relationships can be the reason behind such type of anxiety. Anxiety also occurs in older adults (60+). Fear of separation, declining health, etc. can be the reason behind anxiety in old people.