Temperamental traits of shyness or behavioral inhibition in childhood.
Avoidance, dependence, phobic, introversion type personality traits.
Exposure to stressful and negative life or environmental events in early childhood or adulthood.
Traumatic events leading to persistent anxiety.
A history of anxiety or other mental illnesses in biological relatives.
Physical health conditions, such as thyroid problems or heart arrhythmias.
Caffeine or other substances/medications can produce or aggravate anxiety symptoms.
If the anxiety is very severe then try to breathe in & out of a brown paper bag placing around your mouth & nose.