These guys take about 100 years to get off their backs and seize the institutions. After that, it is all downhill.
One thing that all psychopaths have in common is a desire to limit the information available to everybody else. Information like that at the link above, for example.
The most important side effect of psychopaths running everything is that almost anybody who wants to merely survive will be forced to act like a psychopath themselves. Before you know it, everyone will act like a psychopath just in order to get by and of course there is no such thing as a civilization when everyone in it acts this way. Psychopathy only pays off with a majority of rubes to pluck.
For example, nearly all psychopaths pretend to be altruists interested in universal principles of right and wrong. They cannot succeed in this ruse when everybody else is merely pretending to adhere to these standards themselves. They also cannot succeed where people have a strong instinctual sense of what constitutes universal altruism and can apply these principles. They recognize the psychopath as a fraud.
They thrive at the helm of a declining civilization on it's way out pretending to be altruists and later after it has collapsed they thrive as openly barbaric people in the wreckage that remains. Psychopaths thrive because Homo Sapiens is a busted animal who doesn't work right.
I believe firmly there was no such thing as a Neanderthal sociopath. They never existed. If Neanderthals were psychopaths they would have gotten zero traction with their general tribes and would certainly be sent on the long walk with expulsion. Sometimes Homo Sapiens has expressed the opinion this system sounds cruel ... they never think to look at their own societies to see what results when this genetic hygiene is not adhered to. Before you know it, the rejects will be running the place. Fact.