Emotional Scars Of Modern Slavery Run 'Deeper Than Any Visible Wound'

Some recall getting burned. Others say they've been strangled or attacked by dogs. Many suffer from depression and anxiety. These are only a small sampling of what tens of millions modern slaves endure daily, researchers in London reported Wednesday.

The study, published in The Lancet Global Health, is the largest one, so far, to detail the mental and physical health of people who have survived human trafficking.

Researchers interviewed more than 1,000 men, women and children in Southeast Asia who were forced into sex work, commercial fishing, agricultural businesses, street begging or other labor-intensive industries. Each person was rescued by local organizations two weeks prior to the interviews.

Thazin Mon Htay, 14, has scars on her arms from infections she caught while peeling shrimp for 16 hours a day, seven days a week. She and her father were able to gain their freedom from the shrimp shack after their relatives paid off their debts.

Steve Sapienza/Pulitzer Center on Crisis Reporting for NPR

"Most research to date [on human trafficking] have been conducted on women and sex exploitation," says Ligia Kiss, the study's lead author and an epidemiologist at the London School of Hygiene & Tropical Medicine. "There's very little research on men and boys, and specific studies on fishermen are still scarce."

That may be because the public expects men to work hard, says Michele Clark, a human rights advocate at George Washington University. "When you see a [trafficked] man work, you don't see that he sleeps in a room with 20 other people or that he's been given food with worms in it," says Clark, who wasn't involved in the study. "You see them do work that many men do."

"There's something more visible when you see a woman working in the red light district or an image of a prostituted child," she adds.

In the current study, Kiss and her colleagues interviewed the survivors to learn about their living conditions, where they worked and what kinds of abuse they suffered while they were slaves. The team also documented any persisting health problems and symptoms of anxiety, depression and post-traumatic stress disorder.

More than two-thirds of the men interviewed were exploited in the fishing industry, the team found. Many of the fishermen said they worked as long as 19 hours a day, seven days a week, Cathy Zimmerman, of London School of Hygiene & Tropical Medicine and a co-author on the study, told Reuters.

A fifth of all people in the study said they endure some sort of serious work injury, including back and neck damage and the loss of a body part. Most received no medical care while held against their will.

In many instances, the injury wasn't accidental. Almost half of all participants said that they had been sexually or physically abused or both. Methods of violence were often extreme. Many of the participants reported being beaten up, dragged around, cut with a knife and shot at.

In terms of mental health, more than 60 percent of the people interviewed showed signs of depression. Around 40 percent reported anxiety and 38 percent had PTSD.

About 600 people said they never had the freedom to do what they wanted to do. And nearly 200 reported being locked in a room. These people were twice as likely to have poor mental health.

People who survive human trafficking come out traumatized, Kiss says. "They show a range of physical and mental health symptoms that need to be addressed before they are re-integrated into their communities."

Traditionally, many health services for trafficking survivors are available for only a limited time, Clark says. For instance, an organization may help a survivor as long as his or her court case lasts. But, as the study shows, many people suffer mental problems that are chronic and need long-term treatment.

"The emotional scars worn by men, women and children who have been trafficked are far deeper than any visible wound," Clark says.

And the sheer numbers in this study show that the experiences recounted are not isolated cases, Kiss adds.

The study comes ahead of a larger, 140-page report to be released Friday. That version will look more closely at what increases a person's risk of being trafficked.

That report only examines trafficking in Southeast Asia. But the participants in the study are diverse enough, Kiss says, that the data likely apply to slaves around the world.

"There is no single profile of trafficking victims," she says. "We found in our sample men, women and children of all different ages, backgrounds and origins, and trafficked into different sectors of work. It is a widespread phenomenon."