Sigmund Freud prøver å slutte å røyke, og lurer på om han lider av en logisk eller hypokondrisk depresjon

Sigmund Freud skriver til sin venn Wilhelm Fliess i Berlin (her gjengitt i engelsk oversettelse -- originalen er på tysk):

"Since everyone needs the suggestive influence of someone else in order to obtain a respite from his own criticisms, I have in fact not had anything warm between my lips since then (today it has been three weeks); and today I can already watch others smoke without envying them and even again imagine life and work without this support. It has not been long since I reached this point; moreover, the misery of abstinence has been far greater than I ever imaginedóbut that, of course, is obvious. 

It is too distressing for a medical man who spends every hour of the day struggling to gain an understanding of the neuroses not to know whether he is suffering from a logical or a hypochondriacal mild depression."