I ask because ECT seems to upregulate trophic factors, rather than downregulating them. Some sort of hippocampal injury does seem like it could explain memory-related side effects, but it apparently doesn't actually happen (e.g., https://jamanetwork.com/journals/jamapsychiatry/fullarticle/...)
That’s an unreviewed letter to the editor, not an actual research report.
Look, I’m not arguing that ECT is the best thing ever. The side effects are awful for some people, no one understands the mechanism, and so on. However, it sometimes works when other treatments—-which aren’t great either—-fail. Clearly, better therapies are needed all around.