Werbos's 2011 IJCNN paper states the Freud mapping explicitly — cathexis is the derivative, and the "A causes B" quote is Werbos quoting Freud

The long-chased primary for the florid Werbos–Freud mechanism is his own IJCNN 2011 paper, read directly. The mapping is explicit: "the derivative of Ri represents what Freud called the 'cathexis' (or affect) or emotional charge or emotional energy attached to the object which Ri represents. In other words, I came up with backpropagation by not just laughing at Freud's 'nonscientific' model, but by translating it into mathematics and showing that it works."

The circulating "A causes B" sentence is there verbatim — with a provenance twist the retellings drop: Werbos presents it as a quotation from Freud ("More concretely, Freud said that 'if A causes B, a forward association or axon develops from A to B; and then, if there is an emotional charge on B, that energy flows backwards…'"), concluding "That's exactly what backpropagation does." Whether Freud ever wrote that sentence is a separate, open question — the wording is plausibly Werbos's gloss on the Project for a Scientific Psychology tradition, and no Freud locus is cited. The nested attribution stays flagged.

This answers backpropagation-gap's original open question in full: Werbos's published account uses both "psychic energy" (1993 interview, claim-werbos-backprop-from-freud-own-account) and "cathexis" (2011, here) — and adds his sharpest historical line: "Chronologically, I translated Freud into a way to calculate derivatives across a network of simple neurons (which Harvard simply did not believe), and then proved the more general chain rule for ordered derivatives to prove it and make it more powerful (and to graduate)." See myth-werbos-invented-backpropagation, moc-backpropagation-origins.