The issue here is that the theory that predicts that CBT should be effective is called “Stoicism” and has been around for a long while prior to the concept of a psychological research process.
If you are looking for a therapy or action that arose from psychological theory directly, I would recommend looking into the treatment of PTSD (not even recognized as a treatable condition until the 1970s) or something—CBT has been informed and refined by the research process, but its underpinnings existed prior to the research process itself.
The issue here is that the theory that predicts that CBT should be effective is called “Stoicism” and has been around for a long while prior to the concept of a psychological research process.
If you are looking for a therapy or action that arose from psychological theory directly, I would recommend looking into the treatment of PTSD (not even recognized as a treatable condition until the 1970s) or something—CBT has been informed and refined by the research process, but its underpinnings existed prior to the research process itself.