Understanding mental illnesses - Juice of the books

One out of every four of us suffers each year from a problem related to mental or psychological health, and anxiety and depression alone affect more than 500 million people around the world. Why do these issues spread on such a wide scale? And what is it that makes our modern life have this impact on our mental and psychological health? And why is there still so much confusion around these issues? And why do we still continue to stigmatize discussions about such topics?