TORONTO -- A significant proportion of high school students appears to be consuming high-caffeine energy drinks, and for some of them at least there seems to be a link with mental health issues, substance use and sensation-seeking behaviour, a study has found.
The findings have prompted the researchers to call for a reduction in the amount of caffeine in energy drinks and reduced access to the beverages for teens.
In the study of more than 8,200 high school students in Atlantic Canada, researchers at the University of Waterloo and Dalhousie University in Halifax found that about two-thirds of respondents reported consuming an energy drink in the previous year.
About one in five students said they drank the beverages once or more each month, said the study published in the journal Preventive Medicine.
"We also found something very interesting," said principal investigator Sunday Azagba, a researcher at the Propel Centre for Population Health Impact at the University of Waterloo in southwestern Ontario.
"The more intense users tend to be more likely to be depressed, they're more likely to have substance use," he said, referring to alcohol and marijuana.
Sensation seeking -- taking part in novel activities that provide excitement -- also was higher among those who reported consuming energy drinks compared to those who don't imbibe the caffeine-charged drinks, the researchers found.
"While it remains unclear why these associations exist, the trend is a concern because of the high rate of consumption among teenagers," said Azagba. "These drinks appeal to young people because of their temporary benefits like increased alertness, improved mood and enhanced mental and physical energy."
The study, based on data from the 2012 Student Drug Use Survey of high school students in Nova Scotia, New Brunswick and Newfoundland and Labrador, found that younger teens were more likely to consume energy drinks than their older peers.
"Marketing campaigns appear designed to entice youth and young adults," said Azagba, noting that brand names like Monster Energy, Red Bull and Rockstar Energy can be appealing to young people.
"It's a dangerous combination, especially for those at an increased risk for substance abuse."
Kathleen Miller, a senior scientist at the Research Institute on Addictions at the University at Buffalo, said the findings are troubling but not surprising, as they're in line with the body of emerging evidence on energy drinks and their potential effects.
The study's findings on the tie-in between sensation seeking and energy drink consumption are among the strongest "we've encountered yet," she said.
While clearly intended to provide a bit of a caffeine buzz, most regular or "mainstream" energy drinks contain about the same amount of the stimulant as a cup of coffee, Miller said Thursday from Buffalo. "So it's not just the caffeine. There's something else going on here.
"I think it's more to do with the way these energy drinks are subculturally understood, the way they're marketed and the narrative behind them. The whole message is take risks, live on the extreme, live on the edge," she said, pointing out that Red Bull, for instance, is a major sponsor of virtually "every extreme sport on the planet, literally."
Energy drinks have been associated with a number of adverse health effects, including cardiovascular symptoms, sleep disorders, nervousness and nausea. The side-effects are caused by the beverages' high concentration of caffeine.
"Given the negative effects of excessive caffeine consumption as well as the coincident occurrence of the use of energy drinks and other negative behaviours in teens, the trends we are seeing are more than cause for concern," said Azagba.
In recent years energy drink consumption has skyrocketed. In the U.S. alone, sales are expected to reach $20 billion in 2013.
"In our opinion, at the very least, steps should be taken to limit teens' access to energy drinks, to increase public awareness and education about the potential harms of these drinks and to minimize the amount of caffeine available in each unit," said Azagba.
"This won't eliminate the problem entirely, but steps like these can help mitigate harm to our youth that appears to be associated with consumption of these drinks."
The Canadian Beverage Association (CBA), which represents most manufacturers of non-alcoholic beverages in Canada, said the study findings reflect only an association, not causality, as the researchers themselves admit.
"The use levels reported by the researchers reinforce the fact that the vast majority of teens, over 80 per cent, rarely or never consume energy drinks," the association said in statement. "Further, there is no evidence -- here or anywhere else -- to indicate that the consumption of energy drinks in any way led to substance abuse or to the sort of behaviour associated with substance abuse."
Noting that energy drinks are regulated in Canada and have a capped caffeine content, the CBA said "contrary to the misperception perpetuated by this paper, most mainstream energy drinks contain only about half the amount of caffeine of a similar size cup of coffeehouse coffee."
Miller, who was not involved in the study, is researching the connection between sexual risk-taking and the use of energy drinks mixed with alcohol -- which many researchers deem a dangerous combination.
"What we're finding is that drinking them together seems to put you at greater risk than just drinking alcohol," she said, suggesting that the stimulating effect of caffeine in energy drinks may mask the effects of alcohol, so a person may not realize their level of impairment.
"When you drink alcohol alone, it makes you slower, it makes you sleepy and it makes you stupid because it has an effect on cognitive judgment," she said. "What the caffeine does is take away the sleep part and reduce the slow part.
"You're still stupid, but you're in a better position to do something about it. So it's a recipe for trouble."
