Freud's various cathexis

The word "cathexis" was invented by James Strachey in his translation of Freud's works. Freud had a few types of cathexis, including hypercathexis and decathexis, as an explanation for human processing of emotions.

The term cathexis is an English translation coined by James Strachey for Freud's German term "Besetzung". The German word means "occupation" or "investment" (as in troops occupying a position, or capital invested in an enterprise). Strachey created the "cathexis" term based on Greek words.

Cathexis was Freud's idea of energy or standard emotional investment. Two types of cathexis:

Hypercathexis

When you put excessive or additional investment, focus into something. Examples might be in grief - processing the memories of a person or a symbolic object. Freud used the term in his 1917 essay Mourning and Melancholia, to represent the psychological labor required to get over a loss. The ego brings up every memory, expectation, and hope tied to the lost person. Each memory is charged, and the mind "tests" reality against that memory.

In Melancholia (what we would today call clinical depression), the hypercathexis goes wrong. In the DSM this is known as Prolonged Grief Disorder - where a person is 'stuck'

Decathexis

Withdrawal of your emotional and mental energy from something, e.g. removing your investment. This is the final step of mourning, which could also apply to a relationship - someone unconsciously begins to detach emotionally.