I'd say that generally speaking I have not. I've made it to a point in my career where I interact with the top management at Fortune 100 companies and I have not at all found them to be psychopathic or power-hungry. Actually generally the opposite: those traits seem to be selected against.
There are of course counter examples but I'd argue they're rare.
I'd say that you'll find the psychopaths and power-hungry individuals in the middle layer of companies with the "do nothing" bureaucrats at the bottom of the management hierarchy, often without any formal people management titles at all.