Freud does not give actual case material, but his clinical description is as follows:

There are certain people who behave in a quite peculiar fashion during the work of analysis. When one speaks hopefully to them or expresses satisfaction with the progress of the treatment, they show signs of discontent and their condition invariably becomes worse. One begins by regarding this as defiance and as an attempt to prove their superiority to the physician, but later one comes to take a deeper and juster view. One becomes convinced, not only that such people cannot endure any praise or appreciation, but that they react inversely to the progress of the treatment. Every partial solution that ought to result, and in other people does result, in an improvement or a temporary suspension of symptoms produces in them for the time being an exacerbation of their illness; they get worse during the treatment instead of getting better. They exhibit what is known as a ‘negative therapeutic reaction’.