The distinguishing mental features of melancholia are a profoundly painful dejection, cessation of interest in the outside world, loss of the capacity to love, inhibition of all activity, and a lowering of the self-regarding feelings to a degree that finds utterance in self-reproaches and self-revilings, and culminates in a delusional expectation of punishment. This picture becomes a little more intelligible when we consider that, with one exception, the same traits are met with in mourning. The disturbance of self-regard is absent in mourning; but otherwise the features are the same. Profound mourning, the reaction to the loss of someone who is loved, contains the same painful frame of mind, the same loss of interest in the outside world—in so far as it does not recall him—the same loss of capacity to adopt any new object of love (which would mean replacing him) and the same turning away from any activity that is not connected with thoughts of him. It is easy to see that this inhibition and circumscription of the ego is the expression of an exclusive devotion to mourning which leaves nothing over for other purposes or other interests. It is really only because we know so well how to explain it that this attitude does not seem to us pathological. — Freud, Mourning and Melancholia.