Just a few weeks into her deployment as a medic working with detainees at Guantanamo Bay, Navy corpsman Nichole York started having nightmares.

“I was being attacked by detainees,” she said of the dreams she had during her nine-month deployment in 2010. “I had nightmares where they would somehow get ahold of me and grab my hair and slam my face off a steel door.”

York felt totally isolated and often afraid; to cope, she started drinking heavily. But her experience of suffering, largely in silence, was hardly unique among the 28,000 troops who have served at the U.S. military prison since it opened in 2002 to indefinitely detain captives in the “war on terror.”

Between 2008 and 2011, the joint task force that operates the detention facility secretly evacuated at least 19 troops who had worked in detainee operations due to severe “behavioral health reasons,” according to an Army Institute of Public health study obtained exclusively by VICE News.

Watch VICE News Tonight for more on Guantanamo troops’ experience with post-traumatic stress, Tuesday, Oct. 25, at 7:30 ET on HBO.

This study, combined with two internal military reports on the mental health of troops and interviews with two former Guantanamo guards, show that the invisible wounds of war largely associated with combat-related deployments also affected troops who worked at the detention facility. President Obama has said he still hopes to close the prison, located in an isolated corner of the 45-square-mile naval base that overlooks Guantanamo Bay in southeastern Cuba, by the time he leaves office. At its peak, Gitmo held 779 detainees; today, 60 remain.

For years, journalists have tried to obtain information from the military about whether Guantanamo personnel suffer from post-traumatic stress during and after their deployments. The military never supplied any figures, but in 2010 the Army Institute of Public Health conducted a behavioral health study at the base after a number of troops were evacuated. A year later, two reports were prepared. The findings, which have remained secret until now, paint a dire picture of deteriorating mental health among personnel who served there.

The study found that of the 1,422 troops who were surveyed, 565 developed behavioral health conditions and showed signs of post-traumatic stress that were directly associated with their Guantanamo deployments. Nearly 300 who were screened, or 1 in 5, were considered a “high [behavioral health] risk,” meaning they had suicidal thoughts or a behavioral health condition, such as anxiety or severe depression, requiring “intensive medication management and/or therapy.”

The study noted that the Army did not pre-screen soldiers to determine whether they suffered from behavioral health conditions before they were sent to work with detainees, though it also found that 75 percent of the troops who were evaluated did not have pre-existing behavioral health conditions before arriving at the base. (The Navy, on the other hand, did conduct pre-screenings.)

The highest rates of positive screening for behavioral health conditions were found among Army and Navy troops whose work required them to have “routine detainee exposure” — interacting with detainees for an hour or more per day. The study said that within the Army, troops who worked in detainee operations “had greater positive screenings for suicidal ideation, severe depression & trouble sleeping,” while Navy troops showed “greater positive screenings for severe PTS [post-traumatic stress], aggressive behavior & problematic alcohol use.”

Forty-four percent of personnel surveyed engaged in “potentially hazardous alcohol use,” according to the study, and that use was “highest” within the unit that worked directly on detainee operations. Forty-four percent of those in the Navy specifically said their deployment was “harming my relationship with my spouse/significant other” and exacerbating stress associated with 12-hour work shifts.

The severity and rate of behavioral health conditions affecting Guantanamo troops — aside from alcohol use — was on par with U.S. troops who served at detention facilities in Iraq.

VICE News obtained the reports from United States Southern Command, which oversees the joint task force that operates Guantanamo, in response to a 3-year-old Freedom of Information Act lawsuit.

The study found that the stress troops experienced during their average nine-month deployment was due in part to poor living conditions — troops felt the detainees received better food than they did, and 82 percent of Army and 60 percent of Navy troops surveyed said that overall, detainees were treated better than they were. Troops also cited an inability to “react” to detainees’ verbal and physical abuse, and inadequate training prior to being sent to Guantanamo as contributing to their stress.

Andrew Turner, a Navy petty officer first class when he was discharged, served at Guantanamo in 2009 and 2010. Both he and Nichole York were members of Task Force Platinum, the military unit that works out of the infamous and top-secret Camp 7, where Khalid Sheikh Mohammed and 14 other former CIA captives are held. Both York and Turner said they had no idea what Task Force Platinum was before they arrived, and that they did not receive any special training to deal with the high-value detainees.

“We were taught how to do forced cell extractions,” said Turner, now 43, referring to a procedure in which guards in riot gear restrain and remove a combative detainee from his cell. “We were taught how to cuff detainees in different ways. We had a few days of combatives training, which is the Army’s version of mixed martial arts…. I felt incredibly unprepared and very vulnerable.”

VICE News made numerous email and telephone queries over the past month to spokespeople for the Army, the Navy, and the Department of Defense seeking comment on the Army Institute of Public Health study and the treatment of troops before and after their deployment to Guantanamo. Those spokespeople directed us to Capt. John Filostrat, a spokesman for the detention facility. When VICE News asked Filostrat about the study and York’s and Turner’s deployments, he said he could not answer questions about individual service members nor could he answer questions about the study because he was not familiar with it.

Turner and York spoke with VICE News about their Guantanamo experience in the hopes that it would encourage current and former Gitmo troops who suffer from PTSD symptoms to seek diagnosis and medical treatment. Because they worked at a top-secret camp whose location and operational procedures are highly classified, neither Turner nor York would discuss individual Guantanamo detainees with whom they interacted or the extent of their work with Task Force Platinum. No other member of Task Force Platinum has ever spoken publicly about Camp 7.

Turner initially thought his deployment to Guantanamo would be a “cakewalk,” he said. He wasn’t alone. According to the study, before being sent to Guantanamo, 70 percent of troops surveyed “perceived the assignment as less stressful than a combat deployment.” But once they got to work, only 40 percent still believed that — and among the troops who interacted directly with detainees, the share was even smaller: 25 percent.

York was 20 years old at the time of her deployment in 2010. When she arrived on the island and discovered she would be working with high-value detainees — and that she was the only female medic on Task Force Platinum — she wept.

“We got in our temporary rooms, and I was the only female,” she said. “I literally sat there and bawled for three days…. I kind of thought like, where the fuck am I, and what the fuck is gonna happen? Or what did the Navy get me into?”

Even though her deployment did not entail physical combat, “mentally [and] emotionally, it’s combat.” She says she has nightmares to this day about being attacked by detainees.

Turner, however, did suffer physical harm during his deployment. Just two weeks in, his hand was crushed during a forced cell extraction when he and a team of guards tried to prevent a detainee from slamming his own head into the concrete floor of his cell.

“I was so fucking scared, and I still have nightmares of that day,” Turner said. “I was trying to keep that fear down inside me. That was the only way I could deal with it. To just be twice as tough as everybody else, when really inside I was scared to fucking death…. You just didn’t know what was coming around that next corner, and it was 99 percent boredom and then 1 percent just pure, unadulterated craziness.”

Turner never regained full use of his hand; the injury effectively ended his military career.

York and Turner’s combined 15-month deployments to Guantanamo have left them with profound psychological scars; Veterans Administration doctors diagnosed both with PTSD.

“Each day I’ve got to figure out how I’m gonna function, and it sucks,” Turner said. “I didn’t have to do that before. I don’t like crowds; I used to not have any problem with them, but now they cause me to have a little bit of a panic issue. Loud noises [and] really bright lights kind of can cause me some issues. These are all things that weren’t going on before I went on that deployment.”

Both York and Turner said they were aware that Guantanamo had a facility that assisted troops with emotional and psychological stress but that seeking treatment there was not encouraged and carried stigma. It wasn’t until they both returned to the mainland that they realized something was wrong and they needed help. Their spouses pushed them to get it.

A spokesperson for the Guantanamo facility said anyone on the joint task force can take advantage of counseling on the base to deal with depression and stress through the Joint Stress Mitigation and Restoration Team.

The Army public health study recommended that Southern Command work with the joint task force to “revise pre-deployment training to be more mission-specific, better preparing troopers mentally and emotionally for what to expect by making the training.”

Additionally, the study recommended the military pre-screen all troops prior to their deployment to Guantanamo to identify pre-existing behavioral health conditions in order to prevent “those at increased risk for negative behavioral health outcomes from being assigned” to the base.

“This would, in turn, likely reduce the number of soldiers evacuated from [Guantanamo] for behavioral health conditions,” the study said.

Filostrat, the Guantanamo spokesman, would not confirm whether the study’s recommendations were implemented.