A Pentagon study from 2008 claimed that Russian President Vladimir Putin has Asperger's syndrome, giving him a need to exert "extreme control" when faced with crises, according to the report released Thursday.

Experts studying his movements and facial expressions in video footage theorized Putin's neurological development was disrupted in infancy, giving him a sense of physical imbalance and a discomfort with social interaction, according to the report by the Pentagon's internal think tank, the Office of Net Assessment.

"This profound behavioral challenge has been identified by leading neuroscientists as Asperger's Syndrome, an autistic disorder which affects all of his decisions," wrote the study's author, Brenda Connors, a senior fellow at the US Naval War College.

"During crisis, to stabilize himself and his perceptions of any evolving context he reverts to imposing extreme control," wrote Connors, who has analyzed the body language of other world leaders.

USA Today first revealed the study in a report Wednesday, following a Freedom of Information request.

Putin's condition also can prompt him to "withdraw from social stimulation as he did at the time of the Kursk nuclear submarine incident" in 2000, when a Russian sub sank in the Barents Sea, the study claimed.

The theory about Putin's condition could not be definitively confirmed without a brain scan, the report said. But experts cited the Russian president's body movements and "microexpressions" as indicators of Asperger's, a high-functioning form of autism.

- Seeing Putin's 'soul' -

Since coming to power more than a decade ago, Putin has vexed the United States. Washington experts were taken aback by the Russian president's decision to annex the Crimean peninsula last year and back pro-Moscow separatists.

Former president George W. Bush once famously said he looked his counterpart in the eye and was able to see "his soul." But the Pentagon study claimed Putin's unrelenting stare reflected a neurological abnormality and an inability to pick up on social cues.

His condition meant that Putin would display a "hypersensitivity" and "a strong reliance on the fight, flight and freeze responses" instead of a more nuanced social behavior, it said.

Putin is uncomfortable presenting his ideas to "large audiences" and his neurological "challenge" meant that he "simply lacks trust in human interactions," it said.

The study cited a neurobiologist, Stephen Porges, saying that Putin had a form of autism. But when contacted by USA Today, the psychiatry professor at the University of North Carolina said he never saw the final report and was not ready to give a definitive view on whether Putin had Asperger's syndrome.

The Pentagon played down the study, saying it apparently never made its way to the desk of the defense secretary or other top decision makers.

"The Office of Net Assessment did not send these reports to the secretary, and are not aware of any requests from any DoD (Department of Defense) leaders to review these reports," Lieutenant Colonel Valerie Henderson, a Pentagon spokesperson, told AFP.

All indications were that "the reports remained in the office," she said.

The same office paid for another study in 2011 by the same author, analyzing Putin and then-president Dimitry Medvedev, based on their body movements. The report portrayed Medvedev as an "action man" who saw situations in black-and-white terms, while Putin was described as more of "chess player."

The study recommended US officials present Putin with "meaty policy research and white papers" to satisfy his craving for information.

But the report's author, Connors, argued that examining the body movements of leaders and their potential "to predict behavior and decisions is as potent an instrument as an evolving weapon system."

At the start of the US-led invasion of Iraq in 2003, American experts on nonverbal communication were able to confirm that a puffy-looking man in an army uniform speaking on state television was indeed Saddam Hussein and not an imposter, Connors wrote in a 2006 article.