Read Dianetics. Then read Ellis' article on REBT. Dianetics came out in 1950; Ellis was published in 1956. Both are based on Jung, who rejected Abreaction because he said, basically, it was unreliable because the subject may invent details. But if those details were "real" or "invented" they still represent reality to the subject, so to the subject those "imaginary" details are just as real and, therefore, still influence behavior, emotion, and thinking.
Get past the 50's racism and the bullshit about thetans and diabetes being character faults; focus just on the science and you can see Dianetics predates, and is, modern cognitive therapy made understandable for the lay person. Whatever you think of Hubbard, he was a communicator.