It's a big mistake to assume Russian President Vladimir Putin is a "psychopath" as there is no evidence to suggest that he is, according to clinical psychologist Dr Jordan Peterson.

Sky News Australia host Piers Morgan asked Dr Peterson whether former US president Donald Trump could be a "psychopath".

"I don't think that he's a psychopath," Dr Peterson said.

"It's very easy to demonise someone that you don't approve of.

"I think it's a mistake to assume that Trump is a psychopath – I think it's a big mistake.

"I think it's a big mistake to assume that Putin is a psychopath – I think it's easy to do that but I don't think the evidence suggests that. You don't want to throw those labels around casually."