Anxiety is something we all experience from time to time. Most people can relate to feeling tense, uncertain and perhaps fearful at the thought of sitting an exam, going into hospital, attending an interview or starting a new job. You may worry about feeling uncomfortable, appearing foolish or how successful you will be.  In turn, these worries can affect your sleep, appetite and ability to concentrate.  If everything goes well, the anxiety will go away.

Short-term anxiety can be useful. Feeling nervous before an exam can make you feel more alert, and enhance your performance. However, if the feelings of anxiety overwhelm you, your ability to concentrate and do well may suffer.

Anxiety can be triggered by a number of factors. Something distressing may have happened to you in the past, and because you were unable to deal with the emotions at the time, you may become anxious about encountering the situation again, just in case it stirs up the same feelings of distress.

You may worry about the future. Sometimes, if we feel we are not in control of different aspects of our lives, we can start to feel anxious about events beyond our control, such as the threat of war, of being attacked, of developing an illness, or losing our job.

Feeling anxious can also be a learned response - something that you picked up early on in life. Your family may have tended to see the world as a hostile and fearful place, for example. Research suggests that people may even inherit a tendency to be more anxious. We all become anxious under pressure, but one person may succumb more easily than another, because of a mixture of personality, current circumstances and childhood experience.

On a daily basis, caffeine, excess sugar, poor diet, tiredness, stress and the side effects of certain medication can also cause anxiety.

After a while, people can start to fear the symptoms of anxiety, especially feeling out of control. This sets up a vicious circle. They feel anxious because they dread feeling the symptoms of anxiety, and then they experience those symptoms because they are having anxious thoughts.