So, thanks to @hood-ex, I had to write this, because there is much of Lloyd de Mause's work which is, simply not factually true. (No relation to the fictional field of Asimov's Foundation series, though they share some similarities.)
So, where to begin? Perhaps the dearth of actual academic departments of psychohistory. (There are none. Partially because they can't decide if it belongs in Psychology or in History, and partially because de Mause is a Freudian at the end of the day. More on that in a bit.)
So, Freud, psychoanalysts are very reverent toward their founder. Freud believed in recapitulation theory (long-discredited among developmental biologists), so psychoanalysts must believe in recapitulation theory. (In particular, Freud viewed the Oedipal/Electra as recapitulating a patricidal past.) De Mause similarly sees postpartum depression as proof of an infanticidal past, and babysitters as proof of a past of outsourcing care of one's children, including pederasty.
Beyond this, Freud is solid gold to psychoanalysts, except, apparently, that part where Freud viewed homosexuality as harmless and incurable; many psychoanalysts offered quack cures to homosexuality. To his credit, and I will credit him when he is right, broken clocks and all, I haven't seen any evidence of de Mause offering such. De Mause himself says Leonardo da Vinci had visions of vultures; this is Freud's conflation of two parts of da Vinci's notes, one being a vision of a swallow and another part about vultures. (But in Freud's work, all birds are phallic symbols; there are so many Indo-European "avian" names for the penis, after all. In English, we have "cock" and "robin". Spanish has "polla". And so on in that manner.)
The simplest problem with de Mause was his hostility to peer review, regarding anyone who disagreed with him in the slightest, even on factual matters such as if children were being sacrificed to Satan in a hidden basement in a daycare center (Hey, sound familiar, anyone? Sound like Pizzagate?) and the children themselves said they were sacrificed. (Yeah, literally, the children told stories of being ritually murdered, but they're better because Jesus showed up and fixed everything. By the way, no one saw the absurdity of this until 1989, over a decade after the first claims of Satanic ritual abuse.)
The absurdities didn't end there. Per de Mause, Japanese women publicly masturbate their sons (gleaned from pages of Jungle King Tar-chan and its phallic humor), but it's a huge secret. (Apparently those two things being incompatible never came to mind.) World War I wasn't caused by imperial rivalries, nor was Nazi Germany (which de Mause conflates with World War I) caused by the culture of antisemitism in Europe; instead, it was all because of German and Austrian parenting practices.
This is actually not new for psychoanalysts. Erikson drew on secondhand reports about Luther's life in his biography of Martin Luther. And we already covered Freud, da Vinci, and vultures.
So, what do we have? People who trust the words of deviants, the words of very alive self-styled murder victims, plenty of quote mining, second-hand sources (at best), and outright fabrication. We have very discredited theories, urban legend, and conspiracy theories. I have to give psychohistory an F, but I could see how it was popular in the cult-obsessed 70s.
