I assume the reason he retracted was lack of evidence, but it really doesn’t excuse the fact that the whole procedure is methodologically flawed. There’s is no question to me that dissociatives can cause brain damage if used excessively. Onley’s Lesions appear to NOT be the cause of DXM-related brain damage in primates. I believe it’s excitotoxicity causing the problem.
There is quite a bit of DXM health info here.
It should also be mentioned that the lesions are believed to be caused by all dissociatives (NMDAR’s) but in the trials DXM seems to be the favored drug. Why? What about all of those people who are chronic K-heads for years and step out of their addiction mentally unscathed?