The juxtaposition of melancholy and sadness is justified by the general picture of both conditions. The causes for both diseases also coincide, being reduced to the influences of living conditions in those cases where these causes can be established. Sadness is always a reaction to the loss of a loved one or an abstract concept that has replaced him, such as fatherland, freedom, an ideal, etc. Under the same influence, melancholy occurs in some people instead of sadness, which is why we suspect them of a morbid predisposition. It is also quite remarkable that it never occurs to us to regard sadness as a disease state and to leave it to the doctor for treatment, although it entails serious deviations from normal behavior in life. We hope that after some time it will be overcome, and we consider interference inappropriate and even harmful.
Mentally, melancholy is characterized by deep suffering dejection, the disappearance of interest in the outside world, the loss of the ability to love, the delay in all activity, and a decrease in well-being, expressed in reproaches and insults at one’s own address and growing to the delirium of expectation of punishment. This picture becomes clear to us if we take into account that sadness also differs in the same signs, with the exception of only one sign: with it there is no disturbance of well-being. In all other respects the picture is the same. Severe sadness — a reaction to the loss of a loved one — is distinguished by the same suffering mood, a loss of interest in the outside world, since it does not resemble the deceased, — a loss of the ability to choose some new object of love, which would mean replacing the mourned one, by the refusal of any activity, not relating to the memory of the deceased. We easily understand that this delay and restriction of the «I» is an expression of an exclusive absorption in sadness, in which there are no interests and no intentions for anything else. In fact, such behavior does not seem pathological to us only because we are able to explain it well.
We also accept the analogy that calls the mood of sadness suffering. The correctness of this will become clear to us if we are able to characterize this suffering economically.
What is the work done by sorrow? I think it would be no stretch to portray it this way: the investigation of reality has shown that the beloved object no longer exists, and reality suggests the demand to take away all libido associated with this object. Quite understandable resistance rises up against this; in general, one must take into account that a person does not easily leave the position of libido even when a replacement is foreseen. This resistance can be so strong that there is a withdrawal from reality and the object is held by a hallucinatory psychosis embodying desire… Under normal conditions, respect for reality wins, but its demand cannot be immediately fulfilled. It is carried out partially, with a great expenditure of time and energy, and before that the lost object continues to exist mentally. Each of the memories and expectations, in which the libido was connected with the object, is suspended, acquires an increased active force, and the release of the libido takes place on it. It is very difficult to point out and justify economically why this compromise work of demanding reality, carried out on all these separate memories and expectations, is accompanied by such exceptional mental pain. It is remarkable that this pain seems to us understandable by itself. In fact, at the end of this work of sorrow, the «I» becomes again free and liberated from delays.