According to the Hooley text the categories of Depressive Disorders and Anxiety Disorders have many overlapping clinical features and symptoms.  What are they?  What is the point of critical distinction where the anxiety disorders and depressive disorders differ and become distinct diagnostic categories?

Please be sure to consider and respond to all aspects of the question.  Please use complete sentences to write your answers.  Well-reasoned, well-organized, concise, but complete answers to the questions are expected.  Please appropriately cite your references.