The largest survey to date of the health of trafficking survivors has found high levels of abuse and serious harm associated with human trafficking. For the first time, the findings reveal severe mental and physical health problems experienced by men, women and children trafficked for forced labour and sexual exploitation in Southeast Asia. The study, published in The Lancet Global Health, also highlights frequent physical and psychological abuse and extremely hazardous living and working conditions.
Recent estimates suggest that worldwide more than 18 million people are in forced labour as a result of trafficking, although the hidden nature of trafficking and the difficulties in defining it make estimates uncertain. 
The new study, published today (18 February), was carried out by the London School of Hygiene & Tropical Medicine and the International Organization for Migration. It was commissioned and funded by the Anesvad Foundation with additional funding from the IOM Development Fund, and support from the Economic and Social Research Council, UK.
The researchers carried out face-to-face interviews with 1,015 people entering post-trafficking services in Cambodia, Thailand and Vietnam. These participants had been trafficked to work in various sectors including sex work (32%), fishing (27%), and factories (13%).
Researchers asked participants about their living and working conditions, experiences of violence, and health outcomes. They also measured for symptoms of anxiety, depression and post-traumatic stress disorder. 
Almost half of participants (48%) had been physically or sexually abused (or both) and many suffered violence such as knife and dog attacks, burning and choking. Almost two thirds (61.2%) reported symptoms of depression, and approximately two fifths reported symptoms of anxiety (42.8%) and/or post-traumatic stress disorder (38.9%).
Participants who experienced extremely excessive overtime at work, restricted freedom, bad living conditions, threats, or severe violence were more likely to report mental health issues.
Study lead author, Dr Ligia Kiss, Lecturer of Social Epidemiology at the London School of Hygiene & Tropical Medicine, said: "Our findings highlight that survivors of trafficking urgently need access to health care to address a range of needs, and that mental health care should be an essential component of this. Research is needed to identify effective forms of psychological support that can be easily implemented in low-resource settings and in multilingual, multicultural populations."
Key findings on working and living conditions of participants: - 48% experienced physical and/or sexual violence (481 of 1,015 participants) - 35% of women and girls reported sexual violence (198 of 566 women and girls) - 47% were threatened (478 of 1,015 participants) and 20% (198) were locked in a room - 70% of participants with data available worked seven days per week (685 of 985 participants) - 30% of participants with data available worked at least 11 hours per day (296 out of 989)
Key findings on health outcomes among participants: - 22% (222 of 983 participants with data available) had sustained a serious injury at work, such as deep cuts, back or neck injury, eye injury or even losing a body part - Only 28% of these reported receiving medical care for the injury (62 of 222) - Headaches, dizzy spells and back pain were the most prevalent physical health problems - 61.2% of participants reported symptoms of depression - 42.8% reported symptoms of anxiety - 38.9% reported symptoms of post-traumatic stress disorder - 5.2% had attempted suicide in the past month
Dr Cathy Zimmerman, study author from the London School of Hygiene & Tropical Medicine, said: "Our study shows there is no single profile of a trafficked person - we spoke to men, women and children of all different ages, from different countries, and with a range of experiences of exploitation.
"We believe the wide range of labour sectors in which abuse occurs points to the need for greater government regulation, stringent health and safety standards, and regular inspections of sectors that are susceptible to human trafficking.
"Exploitation of human beings is age-old. Although it is disheartening to see that human trafficking exists in such proportions in the 21st century, it is encouraging that various forms of these violations are increasingly recognised for what they are: modern-day slavery."
The authors note some limitations to the study, including the fact that their sample only included clients of post-trafficking services, rather than the general population of trafficked individuals. However, they state that the large sample size across different settings (such as NGO or government shelters, and support centres for women and children across the three countries), enabled them to collect data from a diverse range of individuals. They note that caution must be used when comparing subgroups, as some had small sample sizes.
The study publication comes ahead of a detailed report on the findings along with further recommendations, which will be launched in Thailand on 27 February 2015.
Ligia Kiss, Nicola S Pocock, Varaporn Naisanguansri, Soksreymom Suos, Brett Dickson, Doan Thuy, Jobst Koehler, Kittiphan Sirisup, Nisakorn Pongrungsee, Van Anh Nguyen, Rosilyne Borland, Poonam Dhavan, Cathy Zimmerman, Health of men, women, and children in post-trafficking services in Cambodia, Thailand, and Vietnam: an observational cross-sectional study. The Lancet Global Health. DOI: 10.1016/S2214-109X(15)70016-1
For more information or to request a copy of the paper or an interview, please email email@example.com or telephone +44(0)207 927 2802.
Notes to editors:
Once published the paper will be available to view at the following link: http://www.
 ILO. Global Estimate of Forced Labour: Results and Methodology. Geneva: International Labour Organization, 2012.
 Researchers measured for symptoms of anxiety and depression with the Hopkins Symptoms Checklist and post-traumatic stress disorder with the Harvard Trauma Questionnaire.
About the London School of Hygiene & Tropical Medicine
The London School of Hygiene & Tropical Medicine is a world-leading centre for research and postgraduate education in public and global health, with 3,900 students and more than 1,000 staff working in over 100 countries. The School is one of the highest-rated research institutions in the UK, and was recently cited as the world's leading research-focused graduate school. Our mission is to improve health and health equity in the UK and worldwide; working in partnership to achieve excellence in public and global health research, education and translation of knowledge into policy and practice. http://www.