Gamers and politicians in Germany have been calling for more official support and funding for e-sports, the competitive form of online computer gaming, which has won over millions of fans around the world in recent years.

And yet one leading criminologist has strongly criticised efforts to build up the e-sports community, which he sees as a threat to boys and young men.

Many online tournaments, such as those with football games like FIFA, might seem harmless at first, but they give the boys access to other, more addictive games, says Christian Pfeiffer.

"It's a gateway drug," the long-standing director of the Criminological Research Institute in the German state of Lower Saxony says.

In his view, there is a lack of political discussion of research findings on the impact of e-sports on performance over the past 10 years.

"The nationwide performance crisis of male adolescents and young men is based to a large extent on an increase in the intensity and daily duration of their computer games," Pfeiffer said, citing previous studies.

While there are no empirical findings to suggest that poorer school performance in Germany is solely due to gaming, a look at research in the US suggests that this may be the case.

Research from economists from the US universities of Princeton and Chicago found that the group of 21 to 30-year-old men in particular are less interested in working and spend more time in their own, private computer world, notably playing video games.

"Since 2004, time-use data show that younger men, ages 21 to 30, shifted their leisure sharply to video gaming and other recreational computer activities," the researchers write.

"Over the same period, these younger men exhibited a larger decline in work hours than older men or women."

Education experts, on the other hand, stress that the performance differences between boys and girls cannot be attributed to one cause and can have many reasons - including the school system.

In Germany, the proportion of male youths who spend at least 4.5 hours a day exclusively playing computer games increased from 16% to 24% between 2007 and 2017 compared to the data of a 2007/2008 nationwide youth survey.

"If weekends and holidays are also included in the calculation, every fourth 15-year-old boy [here] spends more time playing computer games than in school lessons," says Pfeiffer.

Researchers in Hong Kong's Department of Health meanwhile have said that while a clear health impact of e-sports canot yet be concluded, the community's potential role in the broader rise in addictions should be watched.

"When gaming activity is being further promoted under the umbrella of e-sports, it seems reasonable to expect an increase in problematic gaming and thus increased prevalence of gaming disorder and hazardous gaming," the authors wrote in the Journal Of Behavioral Additions in 2019.

However, many leading voices in the e-sports community dispute that competitive gaming leads to poorer school performance and say this develops quick responses, a social community and a sense of competitiveness.

Germay's e-sports society ESBD swiftly rejected Pfeiffer's criticism as "not appropriate".

"If someone claims something over 20 years without evidence, it doesn't make the argument any more correct, it just makes it old-fashioned," said ESBD President Hans Jagnow.

"Those who dismiss it as sitting in front of the screen are still stuck in their heads as digitisation refusers in the last century."

The comments come a year after the World Health Organization added addictive digital gaming to its International Classification of Diseases.

The decision to add gaming addiction to the WHO's list triggered protest from the gaming industry, which was worried that intensive playing could become seen as something that requires therapy.

However, the WHO specifies that gaming disorder should only be diagnosed if the addiction lasts for at least a year, and if it significantly damages the player's ability to function in school, at work, or among his family and friends.

 - dpa