Fear, information control and personality disorders, all play a vital role for dictators to maintain power and keep their people under stringent control, a new study has revealed.

Psychologists and sociologists have asserted that dictators place themselves as people's only salvation.

"Our behavior is still affected by what went on thousands of years ago," Alice LoCicero, a Cambridge, Mass.-based clinical psychologist and researcher on leadership and terrorism, said.

"It's easier to understand why it's adaptive and common for people to bond to powerful leaders. In Darwinian evolution, the people who bonded with the leader survived. That instinct got passed along."

LoCicero has studied terrorist leadership and victims of terrorism from all five continents. She says that in some cultures, it's important to show respect to leaders, whether it''s North Korea''s Kim family of dictators or just the local schoolteacher, the Discovery News reported.

"It would be embarrassing to a family or individual if they didn''t show a great deal of respect," she said.

Dictators also have the ability to rule with more practical tools, such as fear and control of information, according to Jerrold Post, director of the political psychology program at George Washington University.

"Controlling information and controlling dissent are part of what goes into maintaining a totalitarian state," Post said.

"Any manifestation of disloyalty or dissent is brutally punished."

Frederick Coolidge, professor of psychology at the University of Colorado, Colorado Springs and colleague Daniel Singer had previously developed a personality test of sorts for dictators and used it to analyze both Hitler and Hussein. Late Jong-il's score came out pretty close.

"For the personality disorders, it appeared that a 'big six' emerged: sadistic, paranoid, antisocial, narcissistic, schizoid and schizotypal," Coolidge and Singer wrote in their 2009 research paper.

"All three dictators also showed evidence of psychotic thought processes," they added.