You've asked a question that psychologists and others have been wrestling with for years. There is no easy answer. It is quite possible that your physical condition has developed independently of your anxiety disorder. However, consistent levels of stress might be a risk factor because stress can affect the blood clotting mechanism. Stress may also have an indirect effect such as increasing blood pressure, decreasing your level of exercise, increasing alcohol, smoking, eating unhealthy foods and so on.
As far as the individual is concerned much more is known about risk factors, but to say that a psychological condition is the single cause of an illness, remains elusive.
Hope this helps.
I wish you well with your treatment.
Jerry