In the most general terms, cathectic energy is the energy attached to various psychic formations. Freud used this expression in two different contexts: one where it clearly designates a libidinal cathexis, and another where by implication the energy in question is of a different nature—neutral or desexualized.
In this last, narrower sense, cathectic energy appears in the letter to Wilhelm Fliess of January 1, 1896, as "free psychic energy," small quantities of energy bound to the phenomena of attention and consciousness. In The Interpretation of Dreams (1900a), cathectic energy is the energy invested in thoughts by the preconscious as opposed to the countervailing "energy of the unconscious": "[the primary processes] appear whenever ideas are abandoned by the preconscious cathexis, are left to themselves and can become charged with the uninhibited energy from the unconscious which is striving to find an outlet" (p. 605). Freud would continue throughout his career to maintain this distinction between the energy whose displacements regulate the processes of thought and fuel cathexis, on the one hand, and the countercathexes of the instinct on the other.
As for the origin of this energy, Freud wrote in The Ego and the Id (1923b), for example, that he "reckoned as though there existed in the mind ...a displaceable energy, which, neutral in itself, can be added to a qualitatively differentiated erotic or destructive impulse, and augment its total cathexis. ...It seems a plausible view that this displaceable and neutral energy . . . proceeds from the narcissistic store of libido—that it is desexualized Eros" (p. 44). The adherents of ego psychology have made this supposed neutral energy into the energy powering their "conflict-free ego."
See also: Psychic energy.
Freud, Sigmund. (1900a). The interpretation of dreams. SE, 4-5.
——. (1923b). The ego and the id. SE, 19: 1-66.