There have also been tests that people are aided by writing down or discussing their experiences in detail while under the influence of a medicine that lowered their heart rate. It's mentioned in the podcast I mentioned in a comment. "The science of reframing, and how to do it" by anette prehn

An often overlooked part of why therapy helps is that not only are you receiving new perspectives and coping mechanisms from your therapist, you're talking about it, and essentially reliving it through that recollection, while in a safe environment