Anxiety is an unpleasant  state  that  involves  a  complex  combination of emotions , that  include  fear , apprehension  and   worry. It my exists as   primary brain disorder or may be associated  with  other  mental problems  including other   psychiatric   disorders . It is   often accompanied  by physical  sensations  such as   heart palpitation , nausea  chest pain shortness of  breath or tension   headache