The good news is that nothing could be further from the truth. Yet even from the vantage point of robust good health, I find my senses will still try and tell me the blues are here to stay. If even today this sentiment holds sway for me (albeit momentarily), how much more for the person in the middle of their own life's storm.
This is where the people around the sufferer can be a great help even if they feel inadequate for the task of relating to the depressed/anxious person in a positive and life-affirming way. They can affirm what the sick person cannot. Here is how Abraham Lincoln put it in 1859 when consoling an American crowd in the middle of great turbulence:
"It is said an Eastern monarch once charged his wise men to invent him a sentence, to be ever in view, and which should be true and appropriate in all times and situations. They presented him the words: "And this, too, shall pass away." How much it expresses! How chastening in the hour of pride! How consoling in the depths of affliction! "And this, too, shall pass away." And yet let us hope it is not quite true. Let us hope, rather, that by the best cultivation of the physical world, beneath and around us; and the intellectual and moral world within us, we shall secure an individual, social, and political prosperity and happiness, whose course shall be onward and upward, and which, while the earth endures, shall not pass away."
Apparently as a child, Lincoln had very few books available to read. His stepmother said that Lincoln sought to learn and understand every detail of the texts. She said when something was "fixed in his mind to suit him he never lost that fact or the understanding of it". It may require some repeating to get through to the sufferer that "this, too, shall pass". It certainly took a while with me. It remains one of the most valuable truths I have ever learned.