Mental health, violence and psychological coercion among female and male trafficking survivors in the greater Mekong sub-region: a cross-sectional study

Modern slavery is the term that has emerged recently to encompass extreme forms of exploitation, including human trafficking, forced labor and forced marriage [1, 2]. These abuses are a pervasive global phenomena that have important implications for public health and human rights [1, 2]. Estimates suggest that 40.3 million women, men, and children are in modern slavery situations, with 24.9 million exploited as forced laborers in different economic sectors (e.g., fishing, agriculture, construction, domestic work) and 15.4 million in forced marriage conditions [2]. The Asia Pacific region accounts for the largest number of forced laborers, at 62% of the global total, where four out of every 1000 people suffer from labor exploitation [2].

Perpetrators of trafficking often assert their control and coercion, which are well-recognized tactics related to interpersonal violence (sexual, psychological, or physical), and frequently rely on taking advantage of an individual’s particular vulnerabilities (e.g., age, sex) [3, 4, 5, 6]. For instance, it is known that females trafficked for commercial sex and domestic work are subjected to high levels of sexual violence [4, 6]. Additionally, perpetrators may take advantage of the inherent characteristics of the particular labor sector, such as its informality or engagement of irregular migrants, to assert their power over trafficked individuals [7]. This complex asymmetrical manifestation of power, control and violence over trafficked individuals and the fact that different forms of trafficking tend to be sex specific (i.e., females are more commonly exploited for sex work, men for fishing or construction) suggests that experiences of violence (e.g., sexual, physical or both) and coercion will differ for females and males [8, 9, 10, 11]. However, to date, there has been limited sex-specific or comparative evidence on the mental health impact of human trafficking for different forms of labor exploitation or among culturally diverse populations of females and males (including adults, adolescents, and children). Most research on human trafficking has centered on sex trafficking and females, while other forms of forced labor and trafficking of males remains understudied. This in turn has led to an underestimate of the number of females and males affected by the different forms of exploitation in most locations [12, 13].

Scholars and experts have argued that “exploitation” is at the core of the definition of human trafficking or forced labor and that “coercion” is a key feature [4, 11, 14, 15, 16]. Psychological coercion (threats or deception) and violence (physical, sexual, or both) are interconnected and can be sources of traumatic and chronic stressors [3, 4, 17]. Indeed, trafficked individuals report similar experiences of violence, coercion and corresponding psychological consequences as prisoners of war, torture survivors, survivors of concentration camps, cult members, and victims of domestic violence [3, 4, 18, 19, 20, 21, 22, 23, 24]. Perpetrators exert high levels of power and control over victims’ social, physical, psychological, sexual or economic milieu using systematic organized techniques of disempowerment and disconnection [4, 11, 14].

The substantial inequalities in power and control that are experienced by trafficked individuals are associated with higher levels of physical, psychological, and sexual violence [3, 25]. Deprived living conditions with profound restrictions on basic human needs (e.g., food, water, and shelter) during trafficking, and the fact that enslaved individuals may not be able to predict or control any aspect of their life circumstances, make trafficked individuals more susceptible to chronic disease and mental illness [11, 26, 27, 28, 29]. Studies on human trafficking in females that used screening instruments to assess mental health have reported a very high prevalence of anxiety (48.0–97.7%), depression (52.0–100%), and post-traumatic stress disorder (PTSD, 19.5–77.0%) [26, 30, 31, 32, 33]. Only three studies have evaluated the mental health of trafficked males [34, 35, 36]. One [34] examined symptom associations with different levels of violence, while another reported only descriptive results for 27 males [36]. The third study included only 18 trafficked men who were in contact with secondary mental health services [35], therefore the past evidence is limited.

Studies conducted with trafficked females and males suggest that there are sex-related differences in survivors’ mental health. The present study builds on earlier findings from the Study on Trafficking, Exploitation and Abuse in the Mekong Sub-region (STEAM) [34]. STEAM is a pioneering study as the first and largest health survey of trafficking survivors exploited in various labor sectors among a diverse Southeast Asian population of females and males, including children and adolescents using post-trafficking services [34]. The aim of the study was to examine the experience of violence and coercion in relation to mental health (anxiety, depression, and PTSD) of female and male trafficking survivors. To our knowledge, no studies to date have assessed the sex-specific associations between types of violence or coercion and mental illness in survivors of trafficking. Throughout the paper, the terms human trafficking and forced labor are used interchangeably.

The study advances knowledge about the mental health consequences of various forms of violence and coercion during trafficking among female and male survivors who were exploited in different labor sectors. We found that violence and coercion (receiving personal threats or both personal and family threats) are both independently associated with poor mental health and differed between females and males. For females, experiencing both physical and sexual violence was a strong predictor of symptoms of anxiety, PTSD, and depression, while for males, physical violence with additional threats made with weapons was strongly associated with symptoms of PTSD.

Another key finding in the study was that acts of coercion (personal and both personal and family threats) during the trafficking experience proved to be consistently and strongly associated with anxiety, depression, and PTSD symptoms in both females and males. Coercion in females was particularly strongly related to anxiety and PTSD among those receiving both personal and family threats. This finding on the influence of threats is consistent with previous research on trafficked women [28]. Our results highlight the different coercive experiences between females and males, and indicate that coercion can be as harmful to mental health as any form of physical violence.

Overall, the study results are consistent with past studies of gender-based violence and health trafficking research that report sexual and physical violence to be salient features of the trafficking experience among females [4, 12, 28, 30, 32, 34]. Previous research on human trafficking, gender-based violence and interpersonal violence indicates that experiencing more than one type of abuse (e.g., physical, sexual, and psychological or emotional) increases the probability of having anxiety, depression, or PTSD symptoms as well as the severity of those symptoms [34, 59, 60, 61, 62]. Likewise, our results are in accordance with interpersonal violence (IPV) research that reports that psychological coercion for both men and women is strongly associated with an increased risk of symptoms of depression and PTSD [63, 64, 65].

In sum, violence and coercion for many trafficked individuals is a central element of the trafficking experience [4, 34, 66], and it was a salient feature in the present study. The systematic implementation of coercive tactics used by perpetrators reinforces control, depletes individual psychological resources and ultimately contributes to poor mental health [4, 6]. Sexual and physical violence are powerful methods to terrorize, dominate, and humiliate the enslaved individual, but sexual violence in particular is intentionally meant to produce psychological trauma [4, 15, 66]. We found that experiencing both sexual and physical violence was strongly associated with poor mental health in women and girls.

Beyond the trauma, sexual violence is also associated with an increased risk of human immunodeficiency virus (HIV) and other sexually transmitted diseases that can exacerbate physical and mental health problems [67]. Therefore, experiencing both types of violence, sexual and physical, may be an added burden to the harm inflicted on the mental health of female trafficking survivors.

Physical violence with additional threats made with weapons was an important risk factor for PTSD for males in this population. Threats with weapons are another common method to exert psychological coercion, but this is the first study to document this impact in a population of male survivors of trafficking [4, 68]. However, our finding is consistent with the relatively scant research about the nonfatal use of weapons in the context of interpersonal violence [69, 70]. Threats with weapons allow the aggressor to assert dominance in interpersonal relationships because they convey a pernicious threat, elicit compliance, and create extreme fear and intimidation, all of which are the hallmarks for coercive control [69, 70]. Psychological coercive control, a key feature of human trafficking, is known to have deleterious effects on mental health as it involves terror, fear, isolation, and helplessness which consequently affects an individual’s self-efficacy and autonomy [3, 6, 64].

Although the female burden of suffering both physical and sexual violence was expected and documented in previous research [26, 27, 28, 29, 34, 71], the elevated prevalence for anxiety, depression, and PTSD in this population is of considerable concern. Similar elevated prevalence of depression and PTSD had been observed among populations exposed to mass conflict and displacement in which torture and trauma emerged as the strongest risk factor for PTSD and depression [72]. Overall, these findings are consistent with previous research that highlights the need to amplify our understanding of the diversity and complexity of what constitutes human trafficking and how it is carried out globally in diverse countries and through many labor sectors for females and males [34, 73].

An important limitation of this analysis is the cross-sectional design; hence causality and the temporal relationship between violence, threats, and mental health symptoms (anxiety, PTSD, and depression) cannot be established. Individuals with poor mental health could be more vulnerable to being trafficked or have a history of violence. However, previous studies on human trafficking, violence and women’s health suggest that mental health problems are more likely to be the result of abuse rather than its precursor [3, 26, 67, 74]. Assessment of mental health symptoms was conducted with screening instruments with robust psychometric properties. These instruments are commonly used in general populations in some of the study countries and in post-trafficking services. However, these instruments are not gold-standard diagnostic tools to clinically assess these disorders, therefore overestimation of the prevalence ratio of mental health outcomes is possible. It is also plausible that trafficked individuals under the harshest forms of slavery and exploitation are the ones with worse mental health and may be less likely to be reached in post-trafficking services. In this case, our estimates of the prevalence ratio will be underestimates. Nonetheless, the direction and magnitude of the associations observed are consistent with similar previous studies [26, 30, 32, 34].

The study population represents a sample of survivors of trafficking using post-trafficking services. Service eligibility and screening processes for referral to post-trafficking services may vary between countries as human trafficking is often defined according to the legal framework of the country. Therefore, the results of the study may not be generalizable to the broader population of trafficked individuals. However, this population is likely to be representative of survivors of trafficking receiving post-trafficking services in similar forced labor conditions in the countries in question, as violence and coercion are known to be core components of any human trafficking situation.

Another plausible limitation is underreporting of sexual violence in males. Overall, research on sexual abuse and sexual assault of men and boys in all settings is scarce [75, 76]. Previous studies indicate that the perpetration of sexual violence in males is more common in boys than in adult males [77, 78, 79]. Children, in particular, rarely disclose sexual abuse after the event, and disclosure tends to be a process rather than a single question or interview [76]. Male adults are more likely to be sexually assaulted by multiple assailants and to have weapons used against them [80, 81]. Sexual abuse and violence against trafficked males needs further research as well as consideration of the role that culture plays in sexual violence.

The study has important clinical, public health, and policy implications. The elevated prevalence of anxiety, depression, and PTSD in this sample of survivors indicates that addressing their mental health needs is complex and requires a coordinated, culturally sensitive, holistic, and multi-tiered system approach. Care should include immediate and continuous services (e.g., mental and physical health, social services, safety, housing, legal counsel, economic aid, and community and societal reintegration), which should be provided regardless of an individual’s country of origin, legal status, or participation in legal proceedings against traffickers. Building a network of services prepared to address the complex needs that survivors face after being trafficked is needed [7, 82].

A fundamental element of care for trafficked individuals should involve a collaborative approach and a safe space that prioritizes empowerment of survivors. Service providers need to respect survivors’ perspectives, and acknowledge their rights. Given the diverse demographic background and traumatic experiences endured by trafficked individuals, it is important that service providers be well trained with strong multicultural competencies and knowledge of the various forms of exploitation, abuse, and violence as well as ways to screen for potential cases of human trafficking.

Poor mental health and exposure to traumatic events that involve violence can have long lasting health effects, this is particularly concerning for children and adolescents. Yet, to date, the efficacy of psychological treatments for survivors of human trafficking in Southeast Asia has not been investigated. Western treatments may not fully capture the complexity of the psychological responses that arise from individuals who have experienced human rights violations [83]. However, evidence -based treatments, such as Narrative Exposure Therapy (NET) or Trauma-Focused Cognitive-Behavioral Therapy (TF-CBT), have been used with female survivors of sex trafficking and refugees [84, 85, 86]. NET was originally developed for multiple traumatized victims of organized violence in resource-poor settings, where it could be delivered by trained non-professionals [84]. A modified version of TF-CBT has been developed for children exposed to multiple complex traumas, and it is commonly used in children and adolescents with PTSD [87]. Systematic evaluation on the implementation, delivery, and outcomes of mental health interventions is essential for treatment programs, stakeholders and policy makers to improve care and bring accountability to the care of trafficking survivors.

In conclusion, it is important for policy makers and stakeholders to consider the complex and severe effects that violence and coercion inflict on the mental health of survivors of trafficking. We observed differences in the experiences of violence and coercion in female and male trafficking survivors. We found a substantially elevated prevalence of anxiety (≈ 40.0%), depression (> 50%), and PTSD (> 35%) among survivors of trafficking compared to estimates of the general population in Cambodia (≈ 3.2–3.4%), Thailand (≈ 3.5–4.4%), and Vietnam (≈2.2–4.0%), respectively [88]. Our findings highlight the importance of mental health treatment as an integral part of service provision, recovery and re-integration for female and male survivors. Strengthening mechanisms to protect survivors of trafficking and family members susceptible to retaliation and coercion from traffickers is critical. Further research on the development and implementation of evidence based mental health treatments for survivors of trafficking is warranted. Public health interventions and epidemiological approaches could be valuable to furthering understanding of human slavery within a health equity framework to strengthen individuals’ and communities’ capacities to prevent and address forced labor globally.