Experts who surveyed 171 countries found a clear link between levels of private gun ownership and the likelihood of an individual causing carnage with a firearm.
They also blamed the unusual emphasis placed on success and achievement in American society for the high proportion of mass shooters in the US, home to just 5 per cent of the world’s population.
The research drew on data from the New York City Police Department, the FBI and multiple international sources to correlate gun ownership and mass shooting incidents involving the deaths of four or more people between 1966 and 2012.
Dr Adam Lankford, an associate professor of criminal justice at the University of Alabama, said: “My study provides empirical evidence ... that a nation’s civilian firearm ownership rate is the strongest predictor of its number of public mass shooters.
“Until now, everyone was simply speculating about the relationship between firearms and public mass shootings. My study provides empirical evidence of a positive association between the two.”
He added: “The most obvious implication is that the United States could likely reduce its number of school shootings, workplace shootings and public mass shootings in other places if it reduced the number of guns in circulation.”
Gun ownership is hugely controversial in the US, where the right to bear arms is written into the nation’s constitution under the second amendment of the bill of rights.
President Barack Obama has pushed for stricter gun controls but has been frustrated by the pro-gun lobby, led by the powerful National Rifle Association which has many friends in Congress.
Around 300 million firearms are estimated to be in the hands of civilians in the US. In 2011 a Gallup survey found that 47 per cent – almost half – of all US adults reported keeping a gun in the home.
Speaking at the American Sociological Association’s annual meeting in Chicago, Dr Lankford said the US, Yemen, Switzerland, Finland and Serbia were the five countries in the world with the most private firearms per head of population.
“All five are ranked in the top 15 countries in public mass shooters per capital,” he pointed out. “That is not a coincidence.”
The study excluded domestic incidents or shootings that were primarily gang-related or involved hostage taking or robberies .
It found that mass shooters in the US were 3.6 times more likely to have used multiple weapons than those in other countries.
American mass shooters had claimed an average of 6.87 victims each, surprisingly lower than the 8.81 killed by those in other parts of the world.
This could be due to US police being better trained to respond to such incidents – a side effect of long and grim experience which kept down the number of casualties, said Dr Lankford.
US public mass shooters were also more likely to carry out their attacks in schools, factories or warehouses, and office buildings. Non-US killers tended to strike in military settings, such as bases, barracks and checkpoints.
Private gun ownership was not the only factor in the US. Psychology was also important, with certain individuals being pushed over the edge as they saw their “American dream” shattered.