*Warning* I majored in psychology and I could go on and on about this!!
Some of his behavior definitely points towards sociopathy IMHO (what is now generally called "Antisocial Personality Disorder"). He certainly could be cold, calculating, cruel and callous, even towards people who had long considered him a close friend.
But I think we have to consider him in the context of his life and times. Even his daughter Queen Elizabeth I, who most definitely was
not a sociopath, had people executed when she considered it necessary--most famously in the case of her cousin Mary, Queen of Scots. Back then, when monarchs had virtually unlimited power and people were constantly scheming against you, it was pretty much the law of the jungle: kill or be killed.
Henry was ruthless and extremely narcissistic, and a man who callously tosses one wife aside (Katherine of Aragon), and murders two others (Anne Boleyn and Catherine Howard) is not what anyone would call a nice guy.
I think he may have had some sociopathic traits, but he is a vivid reminder to me of that old saying:
"Power corrupts, and absolute power corrupts absolutely."
I think that definitely happened in Henry's case!! I'd love to hear other people's opinions on this, since I've wondered about it myself.