The US military’s addiction to energy drinks like Rip-It and Wild Tiger is exacerbating mental health issues soldiers acquire during deployment, a new medical study has found. The study found that people who drink more high-caffeine drinks are also less responsive to Post-Traumatic Stress Disorder (PTSD) treatments.

The US military has a bad addiction to powerful energy drinks, with soldiers using the high-caffeine beverages to stave off sleep and retain awareness during long deployments and patrols, the Military Times noted. Being cheap, omnipresent, useful and addictive, nearly half of troops down at least one can of what they colloquially call "crack" each day. Energy drinks now seem as much of a necessity for mission success as body armor and adequate armament.

A study published in Military Medicine in late August found that soldiers who drank multiple energy drinks per day displayed more aggressive behaviors and were also more likely to suffer from mental health problems after the end of their deployment, Task and Purpose reported Tuesday.

The authors defined high energy drink use as consuming two or more drinks per day, which they associated with a higher rate of "mental health problems, aggressive behaviors and fatigue." The number of soldiers found to meet the high use threshold, Military Times noted, was five times higher than previous studies that analyzed the consumption patterns of airmen and non-military youth.

For example, Army Staff Sergeant Matthew Riker told Thrillist that he'd "caught privates filling their CamelBaks with the stuff in lieu of water and sipping it through a straw."

What's worse, a frat-party attitude has developed about who can drink the most — a challenge called a "case race," which is, as Shane Snell, a US Army Ranger-turned blogger put it, when "you and your squad, fire team, gun team, or any other team, try to finish an entire case/24 pack of Rip-Its the fastest."

This, Snell says, "is a really bad idea."

The authors of the study, titled "Energy Drink Use in US Service Members After Deployment: Associations With Mental Health Problems, Aggression, and Fatigue," would likely agree with Snell's sentiment.

For the study, the authors surveyed 627 male infantry soldiers, most of them junior enlisted men between the ages of 18 and 24, seven months after returning from combat deployment, and noted some worrisome trends. For example, 66 percent displayed extreme irritability, while 35 percent had sleep issues, and 29.8 percent suffered from alcohol abuse; 9.6 percent suffered from depression, and 11.2 percent suffered higher rates of PTSD. Soldiers who drank less than one energy drink per week did not show these symptoms at such a high rate.

The authors noted that 75 percent of the surveyed soldiers consumed energy drinks leading up to the month of the survey and that 16 percent "reported continuing to consume two or more energy drinks per day in the post-deployment period."

The authors attributed many of these problems to long-term sleep deprivation caused by high caffeine intake. "Interestingly, energy drink use was associated with fatigue," the authors noted. "This relationship suggests that energy drink use may potentially exacerbate, rather than alleviate, fatigue."