# Genes - some of us seem to be born more anxious than others. Research suggests these problems can be inherited through our genes. But even someone who doesn’t naturally worry can, under enough pressure, become uncomfortably anxious.
# Circumstances - sometimes it’s obvious what is making you anxious. When the problem disappears, so does the anxiety. However, some extreme situations are so threatening that the anxiety goes on long after the event. You can feel nervous and anxious for months or years, even if you were physically unharmed. This is called post-traumatic stress disorder.
# Drugs - recreational drugs like amphetamines, LSD or ecstasy can all make you anxious – for some people, the caffeine in coffee is enough.
# Life experience - bad experiences in the past or big life-changes such as pregnancy, changing job, becoming unemployed or moving house.