I attended a number of [trauma-informed, 'Risking Connection', 'Intentional Peer Support'] trainings. I found the work of Peer Support facilitator Shery Mead (and her current organization: "Mental Health Peers") to be quite comprehensive, and reviewed favorably by NH-Dartmouth Psychiatric Research Center, among other organizations.
I also had attended CISD training with First Responders - in the late 1980's, but I think the recent development of "Police Intentional Peer Support", now in use in Boston, Cambridge, and North Shore municipalities of Massachusetts-in conjunction with the [now international] On-Site Academy of Gardner, Massachusetts, and initiatives such as Leckey Harrison described, to be noteworthy, as I hadn't heard of any adverse outcomes. But I hadn't heard of any 'adverse outcomes' from "Athenian Theater", either.
At a PTSD continuing education conference at the Veterans Administration, some years ago, it was noted that a British journal reported questions about the efficacy of CISD with automobile accident survivors in Britain.
I would hope that the ISTSS (International Society of Traumatic Stress Studies), might have an "Evidence Base", as well as EMDRIA-an international group of EMDR Clinicians, who now have the "O'Shea/Paulsen [EMDR] protocols". The "EENet" (Evidence Exchange Network of Ontario province in Canada) may also have data.
I regret that I had once encountered "an adverse bias" to Bessel van der Kolk's work, at our National Center for PTSD Library, even though it was while I was there perusing his book: "The Body Keeps the Score:...". I'm not sure that all staff there concurred with the one person who said to me: "We don't like him!" [pointing to van der Kolk's name on the book cover].
I hope this is helpful, at this 'late date'.