The link between gaming loot boxes and problem gambling has been "robustly verified", according to a new report.
The report, carried out by researchers at the universities of Plymouth and Wolverhampton, found that loot boxes "are structurally and psychologically akin to gambling".
It also found that large numbers of children are opening loot boxes.
The UK government is already considering whether gambling laws should cover such loot boxes.
The upcoming Gambling Act review is set to look at the question, with the UK's House of Lords already having weighed in to say that loot boxes should be firmly regulated as "games of chance".
Loot boxes are a video game feature involving a sealed mystery "box" - sometimes earned through playing the game and sometimes paid for with real money - which can be opened for a random collection of in-game items such as weapons or cosmetic costumes.
The new research, commissioned by the GambleAware charity, compiles existing research to examine the strength of links between the in-game random prizes and gambling behaviour. It found:
- Of the 93% of children who play video games, up to 40% opened loot boxes
- About 5% of gamers generate half the entire revenue from the boxes
- Twelve out of 13 studies on the topic have established "unambiguous" connections to problem gambling behaviour
- Young men are the most likely to use loot boxes - with young age and lower education correlating with increased uses
The report said that many games use a "psychological nudge" to encourage people to buy loot boxes - such as the fear of missing out on limited-time items or special deals.
"Many gamers do ascribe discrete financial values to loot box contents - based on purchase or resale price - suggesting that many loot boxes meet existing criteria for gambling regulation," the authors wrote.
The big spenders - the crucial 5% for the industry - can spend more than £70 or $100 a month on the boxes, the report said. But those are not necessarily wealthy people who earn lots of money.
"Our research therefore demonstrates that games developers, unwittingly or not, appear to be generating outsized loot box profits from at-risk individuals (these are likely to include both people with gambling problems or problematic patterns of video gaming) - but not from wealthy gamers," it concluded.
Among the authors' recommendations were that any regulation has extremely precise definitions to avoid any possible workarounds; that loot boxes are included in game labelling and age ratings; that the odds of winning items be clearly shown including the average cost of enough boxes to obtain a rare item; establishing spending limits; and more.
Dr James Close, one of the report's authors from the University of Plymouth, said the study had established the link between loot boxes and "problem gambling behaviours".
"We have also demonstrated that at-risk individuals, such as problem gamblers, gamers, and young people, make disproportionate contributions to loot box revenues," he added.
GambleAware's chief Zoe Osmond said the charity was "increasingly concerned that gambling is now part of everyday life for children and young people".
"It is now for politicians to review this research, as well as the evidence of other organisations, and decide what legislative and regulatory changes are needed to address these concerns," she said.
A spokesman for Ukie, the national games industry body, said that game companies had "already taken action" on the issue.
"Probability disclosure has already been introduced to the major game platforms; a new paid random item descriptor was added to the PEGI age rating system to inform players of their presence in games; settings and tools on all major game devices - and in a number of leading games - already allow players to manage, limit or turn off spend," he said.
"We will also continue to work constructively to support our players in partnership with Government and other organisations."