Abstract
Objectives:
Undocumented immigrants are a highly vulnerable population, frequently exposed to violence and trauma in their country of origin, along the migration journey, and in the host country. This study investigates which factors experienced before, during, and after migration influence the development of post-traumatic stress disorder (PTSD). It also investigates whether PTSD relates to high-risk health behaviors in France.
Methods:
We relied on a survey representative of undocumented immigrants attending facilities providing assistance to vulnerable populations in Paris and Bordeaux (France). Analyses relied on several multivariate probit models (N = 1,060).
Results:
Overall, 54.1% of respondents experienced at least one traumatic event, and 17.2% currently suffer from PTSD. Factors associated with an increase probability to develop PTSD are: coming to France for safety reasons (before migration), entering France without appropriate documentation (during migration), food insecurity and poor housing conditions (after migration). PTSD is also associated with an increase probability to engage in high-risk alcohol consumption.
Conclusion:
Although pre-migration factors cannot be addressed by destination-country policies, our findings suggest that interventions targeting deprivation may help reducing PTSD and substance use among undocumented immigrants.
Introduction
In 2024, 918, 925 individuals were found to be present in the European Union (EU) without appropriate documentation. Undocumented immigrants were estimated to account for approximately 0.2% of the total European population [1]. According to the European Commission, an undocumented immigrant refers to a person living in “a new place of residence or transit that takes place outside the regulatory norms of the sending, transit and receiving countries” [2]. Some immigrants entered documented but become undocumented by overstaying their visa. Others entered and stayed undocumented in the destination country.
Undocumented immigrants face legal, social, and economic vulnerabilities making the investigation of their mental health particularly important. They are often exposed to violence throughout their migration journey [3], placing them at high risk of developing post-traumatic stress disorder (PTSD). PTSD is a mental and behavioral disorder that can occur after exposure to a traumatic event. It is characterized by re-experiencing, avoidance, hyperarousal, and emotional numbing, with symptoms persisting for weeks or longer, and significantly impairing social functioning [4, 5].
Exposure to trauma can occur at all stages of the migration (that is, before, during, and after) and may be worsened by precarious living conditions such as, inadequate housing, food insecurity, language barriers, and social isolation in the host country [3, 6]. These conditions can exacerbate trauma, deplete physical and psychological resilience, and increase the likelihood of developing chronic PTSD [7, 8, 9].
A large body of the literature showed that refugees experienced high rates of PTSD, depression, and other affective disorders [10–12]. Existing studies investigated the mental health of undocumented immigrants have relied either on small samples, which limits the statistical power of the analysis [13–17] or on larger but selected samples of specific country of origin [18] or drawn from healthcare facilities [19, 20]. Supplementary Table A1 provides a summary of the sampling characteristics of the above-mentioned studies.
This study investigates which factors experienced before, during, and after migration that influence the development of PTSD. It also investigates whether PTSD relates to high-risk health behaviors in France. To do so, we relied on a representative sample of undocumented immigrants attending facilities providing assistance to vulnerable populations in Paris and Bordeaux (France). We believe this dataset allowed us to contribute to the existing literature for the following reasons. First, by scaling-up the number of observations, which allow to control for important confounding factors and to improve the statistical power of the analysis. Second, other datasets surveyed undocumented immigrants in healthcare facilities, thereby introducing a selection bias toward individuals in poorer health. Third, individuals attending assistance facilities represent a particularly relevant population, as they can be more readily identified and reached through targeted public interventions.
Methods
The empirical analysis relies on data from the “Premiers pas” (first steps) survey. It was designed and conducted by IRDES (Institute for Research and Information in Health Economics, a French research center specialized in health economics), and funded by the French Research National Agency. The survey was launched from February to April 2019 in the greater Bordeaux area and in Paris. The survey protocol followed a two-stage procedure. In the first stage, facilities providing assistance to vulnerable populations were selected—these facilities were attended by immigrants regardless of legal status and by low-income French individuals. These facilities offered various assistance services: administrative supports, food and cloth distributions, hygiene and healthcare services, as well as educational and cultural activities. Among these facilities, 113 mentioned that at least 20 undocumented immigrants came in a typical week, and 63 of them agreed to administer the questionnaire. By focusing on all these services, we extend the existing literature, which has primarily focused on healthcare structures [21, 22]. However, recruiting in facilities providing assistance generate an additional selection bias, as these services may disproportionally attract individuals with higher levels of social and health-related needs.
In the second stage, interviewers (who were chosen to be first- or second-generation immigrants in order to reduce the cultural distance with the respondents. They spoke at least French and English) collected questionnaires in these facilities. They also completed, in a separated document, the characteristics of the facility (i.e., detailing its organization, and any other information that might affect data collection). In each facility, respondents were randomly selected. 49% of these respondents were not within the scope of the survey (because they were French citizens, documented immigrants, or refugees), 8% did not participate owing to language barriers, 42% refused to participate, and 50% agreed.
Questionnaires were displayed in 14 languages. Of those who participated, 75% responded in French, followed by 8% in Arabic, 7% in English, 4% in Spanish, 2% in Russian, and 2% in Portuguese.
To achieve representativeness of the population attending these facilities, survey weights were constructed for each category of facilities. Each facility reported the average number of undocumented immigrants received during a representative week. On the day of the data collection, interviewers also recorded the actual number of undocumented immigrants present at the facility. Weights were then adjusted to correct for discrepancies between the reported weekly average and the actual attendance observed on the interview day. If the number of undocumented immigrants present during the data collection was lower (higher, respectively) than the reported weekly average, the respondents interviewed at that facility were assigned a higher (lower, respectively) weight to compensate for the underrepresentation (overrepresentation, respectively). More details on the data collection and the design of the survey could be found in Supplementary Figures S1–S3 and in [23].
To measure PTSD we followed [9, 24] and constructed a score based on a two-step procedure. First, respondents were asked whether they had ever experienced a traumatic event. This variable is referred as follow: “sometimes things happen to people that are unusually or especially frightening, horrible, or traumatic. For example,: a serious accident or fire, a physical or sexual assault or abuse, an earthquake or flood, a war, seeing someone be killed or seriously injured, having a loved one die through homicide or suicide”. Those who answered positively were then asked the five following questions: over the past month: (1) Have you had nightmares about the event(s) or thought about them when you did not want to? (2) Have you tried hard not to think about the event(s) or avoided situations that reminded you of them? (3) Have you been constantly on guard, watchful, or easily startled? (4) Have you felt numb or detached from people, activities, or your surroundings? (5) Have you felt guilty or unable to stop blaming yourself or others for the event(s) or for any problems they may have caused? Respondents who answered positively to at least three of these questions were considered as having PTSD. This threshold was chosen because it minimizes false negative screening results, which is especially important in primary care settings to facilitate early detection and treatment of PTSD cases that might otherwise go unrecognized. With a cutoff of 3, [24] identified 94.8% of participants diagnosed with PTSD using the MINI (Mini International Neuropsychiatric Interview). In contrast, a cutoff of 4 identified 82.6%, and a cutoff of 5 only 56.2% of diagnosed cases. Our PTSD variable is a binary variable equal to 1 if individuals have such trouble, and 0 otherwise. This constitutes our main dependent variable. The distributions of responses to these variables are presented in Table 1.
TABLE 1
| Variables | % | Sample size |
|---|---|---|
| Have you experienced a traumatic event? | 54,1 | 1,060 |
| If so, over the past month, have you: | ||
| Had nightmares about the event(s) or thought about the event(s) when you did not want to? | 55.3 | 560 |
| Tried hard not to think about the event(s) or went out of your way to avoid situations that reminded you of the event(s) | 59.7 | 560 |
| Been constantly on guard, watchful, or easily startled? | 35.9 | 560 |
| Felt numb or detached from people, activities, or your surroundings? | 19.8 | 560 |
| Felt guilty or unable to stop blaming yourself or other for the event(s) or any problems the event(s) may have caused? | 26.7 | 560 |
| PTSD: Answered “yes” to at least 3 of the above-mentioned questions | 17.2 | 1,060 |
Construction and distribution of the post-traumatic stress disorder variable (France, 2019).
Reading: 54.1% of individuals have experienced a traumatic event, and 17.2% developed a post-traumatic stress disorder. All results take survey weights into account.
High-risk health behaviors are measured using self-reported questions on alcohol, tobacco, and cannabis consumption (a binary variable for each variable). These variables will be further used as the other dependent variables.
The other variables used in the study as independent variables are: gender, age, age at migration, region of origin, migration motives, whether entered France without appropriate documentation, the length of stay in France, the level of French proficiency, the type of facility, the type of housing, and the food deprivation. These variables reflect different aspects of the factors that occur before, during, and after migration. Table 2 provides a complete description of all variables and their respective percentage in the analyzed sample (N = 1,060). Table 3 provides a description of both the traumatic event locations and the distribution of PTSD over the other variables.
TABLE 2
| Variables | Description | % in the analyzed sample |
|---|---|---|
| Female | Binary variable equal to 1 for women, and 0 for men | 29.4 |
| Age at migration | 18–25 years old | 28.0 |
| 26–30 years old | 23.8 | |
| 31–31 years old | 18.1 | |
| 35–46 years old | 20.5 | |
| 46 years old and more | 9.6 | |
| Region of origin | Binary variable equal to 1 for those coming from sub-Saharan Africa, and 0 otherwise | 62.7 |
| Entered France without appropriate documentation | Binary variable equal to 1 for those entering France without appropriate documentation, 0 otherwise | 58.3 |
| Length of stay | Binary variable equal to 1 for those living in France for 5 years or more, and 0 otherwise | 28.4 |
| Coming to France for economic reasons | Binary variable equal to 1 for those reported coming to France for economic-related reasons, and 0 otherwise | 43.0 |
| Coming to France for health reasons | Binary variable equal to 1 for those reported coming to France for health-related reasons, and 0 otherwise | 10.4 |
| Coming to France for political reasons | Binary variable equal to 1 for those reported coming to France for political-related reasons, and 0 otherwise | 23.2 |
| Coming to France for family reasons | Binary variable equal to 1 for those reported coming to France for family-related reasons, and 0 otherwise | 7.5 |
| Coming to France for security reasons | Binary variable equal to 1 for those reported coming to France for security-related reasons, and 0 otherwise | 14.8 |
| Healthcare facilities | Binary variable equal to 1 for facilities providing healthcare services to vulnerable populations, and 0 otherwise | 7.9 |
| Level of French proficiency | Binary variable equal to 1 for individuals answering the questionnaire in French and self-reported having a very good level of speaking and reading French | 20.4 |
| Food deprivation | Frequent | 33,2 |
| Sometimes | 35,4 | |
| Never | 31,4 | |
| Housing | Living in an apartment | 40.3 |
| Living in a shelter or in social hostel | 30.4 | |
| Homeless | 29.3 | |
| Tobacco | Binary variable equal to 1 if individual reported smoking tobacco every day or occasionally, and 0 if they never smoke tobacco | 32.4 |
| Alcohol | Binary variable equal to 1 if individual is an occasional or chronic risk consumera, and 0 otherwise | 16.0 |
| Cannabis | Binary variable equal to 1 if individuals reported smoking cannabis at least once per week, and 0 if they never smoke cannabis | 14.2 |
Descriptive statistics of our sample (France, 2019).
An occasional risk consumer is defined as a person consuming no more than 21 standardized glasses of alcohol per week for a man (or 14 for a woman), and no more than 6 standardized glasses of alcohol, at most once per month (regardless of gender). A chronic risk consumer is defined as a person consuming at least 22 standardized glasses of alcohol per week for a man (or 15 for a woman) or at least 6 standardized glasses of alcohol per week (regardless of gender). These thresholds are used by the AUDIC-C alcohol consumption questions developed by the WHO [25, 26].
Our analyzed sample contains 1,060 observations. All results take survey weights into account.
TABLE 3
| Variables | Traumatic event occurring in | Facing traumatic event | PTSD among those facing traumatic event | PTSD in the analyzed sample | |||
|---|---|---|---|---|---|---|---|
| Country of origin | Migration journey | France | |||||
| Female | 26.6 | 23.1 | 36.2 | 28.8 | 36.8 | 19.5 | |
| At migration | 18–25 years | 29.5 | 37.5 | 31.4 | 29.3 | 36.8 | 20.8 |
| 26–30 years old | 24.0 | 32.3 | 26.5 | 26.9 | 33.5 | 20.5 | |
| 31–35 years old | 17.1 | 17.5 | 12.3 | 16.5 | 22.7 | 11.1 | |
| 36–45 years old | 23.7 | 11.8 | 23.6 | 22.3 | 29.1 | 17.1 | |
| 46 years old and more | 5.7 | 0.9 | 6.2 | 4.5 | 37.3 | 10.3 | |
| Region of origin | Sub-Saharan Africa | 68.1 | 86.1 | 65.5 | 71.5 | 34.4 | 21.1 |
| Entered France without appropriate documentation | 58.9 | 89.6 | 65.3 | 66.1 | 36.3 | 22.2 | |
| Came in France for | Economic reasons | 31.3 | 36.9 | 36.2 | 35.8 | 18.5 | 8.0 |
| Health reasons | 33.5 | 31.4 | 27.7 | 30.2 | 39.7 | 20.1 | |
| Political reasons | 7.2 | 4.4 | 9.6 | 7.7 | 35.9 | 24.2 | |
| Family reasons | 19.4 | 29.5 | 16.5 | 21.5 | 27.5 | 14.3 | |
| Security reasons | 10.4 | 6.9 | 10.2 | 9.6 | 46.2 | 35.6 | |
| Food deprivation | Frequent | 22.2 | 19.1 | 19.8 | 22.9 | 38.0 | 25.1 |
| Sometimes | 43.0 | 32.9 | 41.8 | 38.7 | 31.9 | 18.9 | |
| Never | 34.8 | 47.9 | 38.4 | 38.4 | 21.4 | 7.9 | |
| Housing | Regular apartment | 34.9 | 22.4 | 35.9 | 34.0 | 22.9 | 10.5 |
| Shelter or social hostel | 35.0 | 33.4 | 36.5 | 33.9 | 38.8 | 23.3 | |
| Homeless | 30.0 | 44.2 | 27.5 | 32.1 | 34.1 | 20.2 | |
Distribution of both the traumatic event locations and the prevalence of post-traumatic stress disorder (France, 2019).
Reading: Among undocumented immigrants facing a traumatic event that occurred in the country of origin, during the migration journey, or in France, 26.6%, 23.1% and 36.2% were women. The prevalence of PTSD is 36.8% for women experiencing at least one traumatic event. The prevalence of PTSD is 19.5% for women in our sample. All results take survey weights into account.
Analyses relied on several multivariate probit models. In our main specification, we used PTSD as the dependent variable, and the other variables are used as independent variables. In a second specification, we used high-risk health behaviors as dependent variables (three separate regressions), and PTSD along with the other variables as independent variables. All estimates use survey weights and estimate robust standard errors, accounting for potential heteroskedasticity across surveyed facilities and the types of services provided.
Results
Results of the multivariate probit models are presented in Tables 2, 3. Tables reported marginal effects, which allows the coefficients to be interpreted in percentage points (pp).
Table 4 estimated how demographics (column 1), migration characteristics (column 2), and living conditions in France (column 3) are correlated with PTSD. These sets of variables are included one after the other in the table. Results showed that among the factors that increase the probability of experiencing PTSD, the strongest is facing food deprivation often and sometimes (+9.2 pp and +7.6 pp, respectively). Migrating for security reasons is also strongly associated with a higher probability of experiencing PTSD (+7.4 pp) as is entering France without appropriate documentation (+6.9 pp). Homeless undocumented immigrants and those living in shelter or in social hostels were also more likely to experience PTSD compared to those living in regular appartements (+5.1 pp and +6.2 pp, respectively). It is worth noting that individuals migrating for economic reasons are less likely to experience PTSD (-11.5 pp).
TABLE 4
| Variables | Probability of experiencing a PTSD | |||
|---|---|---|---|---|
| Marginal effects | (1) | (2) | (3) | (4) |
| Female | 0.0460** | 0.0701*** | 0.0438 | 0.0413 |
| | (0.0180) | (0.0265) | (0.0293) | (0.0285) |
| Ref. age at migration:<26 years Age at migration: 26–30 years | −0.00974 | 0.00652 | 0.0197 | 0.0265 |
| | (0.0323) | (0.0242) | (0.0200) | (0.0179) |
| Age at migration: 31–35 years | −0.104*** | −0.0833** | −0.0707** | −0.0646** |
| | (0.0356) | (0.0418) | (0.0342) | (0.0309) |
| Age at migration: 36–46 years | −0.0436 | −0.0162 | −0.0248 | −0.0177 |
| | (0.0523) | (0.0536) | (0.0398) | (0.0467) |
| Age at migration: >46 years | −0.115*** | −0.0756*** | −0.0524*** | −0.0321*** |
| | (0.0227) | (0.00885) | (0.0159) | (0.0124) |
| Region of origin: Sub-saharan Africa | | 0.0618** | 0.00812 | 0.000350 |
| | | (0.0264) | (0.0140) | (0.0182) |
| Length of stay: 5 years and more | | 0.00309 | −0.00354 | 0.0107 |
| | | (0.0468) | (0.0377) | (0.0220) |
| Entered France without appropriate documentation | | 0.102*** | 0.0943*** | 0.0693*** |
| | | (0.0150) | (0.0191) | (0.0220) |
| Very good level of French proficiency | | −0.0182 | −0.0153 | −0.0164 |
| | | (0.0248) | (0.0210) | (0.0193) |
| Came for economic reasons | | | −0.121*** | −0.115*** |
| | | | (0.0114) | (0.00869) |
| Came for political reasons | | | 0.0608 | 0.0494 |
| | | | (0.0429) | (0.0356) |
| Came for family reasons | | | −0.0204 | −0.00321 |
| | | | (0.0426) | (0.0386) |
| Came for security reasons | | | 0.103* | 0.0741* |
| | | | (0.0602) | (0.0439) |
| Came for health reasons | | | 0.0571 | 0.0496 |
| | | | (0.0691) | (0.0541) |
| Healthcare facilities | | | | 0.0251** |
| | | | | (0.0103) |
| Ref. Food deprivation: never Food deprivation: sometimes | | | | 0.0766*** |
| | | | | (0.0153) |
| Food deprivation: often | | | | 0.0926* |
| | | | | (0.0481) |
| Ref. Housing: regular appartment Housing: shelter or social hostel | | | | 0.0621*** |
| | | | | (0.0134) |
| Housing: homeless | | | | 0.0517*** |
| | | | | (0.0133) |
| Observations R-squared | 1,060 0.017 | 1,060 0.052 | 1,060 0.109 | 1,060 0.131 |
Factors contributing to the development of post-traumatic stress disorder (France, 2019).
Reading: Undocumented immigrants who often face food deprivation have an increased probability of 9.2 percentage points to experience a PTSD, by comparison to those never facing such a deprivation.
Coefficients are marginal effects computed after probit models. All results take survey weights into account.
*indicates p < 0.1, **indicates p < 0.05, ***indicates p < 0.01.
It is worth noting that recently arrived individuals might exhibit more pronounced symptoms due to fresh arrival and higher stress levels for being in a new environment. We, therefore, provide a robustness check using the length of stay measured by a categorical variable distinguishing between in France for less than 2 years, from 3 to 5 years, and for more than 5 years (Supplementary Table A2). We also have provided additional results investigating the correlations between PTSD and other mental health symptoms (Supplementary Table A3).
Table 5 followed the same pattern as Table 4 with a focus on the associations between PTSD and three high-risk health behaviors: alcohol, tobacco and cannabis consumptions. The analysis relied on the same sets of demographics, migration characteristics, and living conditions as displayed in column 4 of Table 4. Results showed that PTSD is positively and significantly associated the probability to be an occasional or a chronic risk alcohol consumer (+5.1 pp), but not with tobacco and cannabis consumption.
TABLE 5
| Variables | Alcohol | Tobacco | Cannabis |
|---|---|---|---|
| Marginal effects | (1) | (2) | (3) |
| PTSD | 0.0516*** | 0.00340 | −0.0127 |
| | (0.0149) | (0.0259) | (0.0152) |
| Female | −0.126*** | −0.152*** | −0.118*** |
| | (0.00708) | (0.0221) | (0.00568) |
| Ref. age at migration: <26 years Age at migration: 26–30 years | −0.0165 | −0.0693** | −0.0859*** |
| | (0.0121) | (0.0333) | (0.0260) |
| Age at migration: 31–35 years | 0.0138 | −0.0972*** | −0.0808*** |
| | (0.0190) | (0.0347) | (0.0197) |
| Age at migration: 36–46 years | 0.0977*** | −0.0366 | −0.119*** |
| | (0.0227) | (0.0249) | (0.0302) |
| Age at migration: >46 years | −0.0565*** | −0.109*** | −0.215*** |
| | (0.0167) | (0.0113) | (0.0311) |
| Region of origin: Sub-Saharan Africa | −0.195** | −0.263*** | −0.199** |
| | (0.0832) | (0.0876) | (0.0827) |
| Length of stay: 5 years and more | 0.0380 | 0.0912** | 0.0968*** |
| | (0.0244) | (0.0378) | (0.0248) |
| Entered France without appropriate documentation | 0.0272 | 0.0513 | 0.0434 |
| | (0.0313) | (0.0471) | (0.0287) |
| Very good level of French proficiency | −0.0142 | −0.0799*** | −0.0437 |
| | (0.0164) | (0.0242) | (0.0577) |
| Came for economic reasons | −0.0330* | −0.00236 | 0.0347* |
| | (0.0186) | (0.0148) | (0.0209) |
| Came for political reason | 0.0555* | −0.0288 | 0.0190 |
| | (0.0302) | (0.0278) | (0.0248) |
| Came for familly reasons | 0.167** | −0.0424 | 0.0664 |
| | (0.0656) | (0.0718) | (0.0939) |
| Came for security reasons | −0.000823 | −0.0218 | 0.0352 |
| | (0.0156) | (0.0207) | (0.0273) |
| Came for health reasons | −0.0161 | −0.142*** | 0.00566 |
| | (0.0284) | (0.0460) | (0.0276) |
| Healthcare facilities | 0.0245 | 0.0389*** | −0.0400** |
| | (0.0235) | (0.00730) | (0.0160) |
| Ref. Food deprivation: never Food deprivation: sometimes | 0.0345 | −0.0260 | 0.00217 |
| | (0.0356) | (0.0161) | (0.0128) |
| Food deprivation: often | 0.00507 | 0.0686*** | 0.0554*** |
| | (0.0296) | (0.0183) | (0.0162) |
| Ref. Housing: regular appartment Housing: shelter or social hostel | −0.100*** | 0.0126 | 0.0139 |
| | (0.0197) | (0.0185) | (0.0185) |
| Housing: homeless | −0.0578 | 0.102*** | 0.0620*** |
| | (0.0431) | (0.0237) | (0.0141) |
| Observations R-sqaured | 1,060 0.161 | 1,060 0.233 | 1,060 0.272 |
Association between post-traumatic stress disorder and high-risk health behaviors (France, 2019).
Reading: Undocumented immigrants experiencing a PTSD had an increase probability of 5.1 percentage points to be an occasional or chronic risk alcohol consumer.
Coefficients are marginal effects computed after probit models. All results take survey weights into account.
*indicates p < 0.1, **indicates p < 0.05, ***indicates p < 0.01.
Discussion
Our findings are threefold. First, the prevalence of PTSD among undocumented immigrants living in France is high, reaching 17.2% — at least eight times greater than what is observed in the general French population [27, 28], and much higher than rates reported in other European countries [20, 29]. Second, both pre-migration, and post-migration factors significantly contribute to the development of PTSD. Third, we showed that PTSD is strongly correlated with a high-risk alcohol consumption after arrival in France.
More precisely, we found that, everything else being equal, individuals who migrated for security reasons were more likely than others to develop PTSD. This is similar to the findings showing that negative push-factors such as war, torture, sexual or gender-based violence, or political persecution explained the immigration decision [30–32]. Push-factors are important to consider because individuals are still choose to migrate despite being aware of the risk of fatality occurring during the migration journey and on the uncertainty of finding employment in destination countries [33]. Once in France, social determinants such as housing instability, food insecurity, and alcohol consumption were other important factors significantly associated with the probability of developing PTSD. These results add up to the reasons explaining the unhealthy acculturation effects reported in several other studies on regular immigration [34–37].
Our study faces the following limitations. First, the cross-sectional nature of the data prevents any causal interpretation of our results. Second, important omitted variables might bias our estimates, such as attitudes toward risk. Risk-taking individuals are found to be more likely to migrate [38, 39], are less prone to healthy behaviors [40–42]. Its omission might lead to spurious correlation between PTSD and the other variables. Third, the associations between PTSD and living conditions might suffer from reverse causality issue. Poor living conditions may be a trigger for and a consequence of PTSD. That is, individuals with poor living conditions are more likely to develop PTSD, and those facing PTSD may me more likely to have poor living conditions. Fourth, while our sample is representative of undocumented immigrants attending facilities providing assistance to vulnerable populations in Paris and Bordeaux, it may not be representative of all undocumented immigrants living in France. In particular, our sample mainly consists of young men from sub-Saharan Africa, many of whom have lived in France for only a few years. This limits the generalizability of our results, particularly if there is self-selection by individuals of specific origins into assistance-providing facilities. Fifth, our PTSD measurement is based on self-reported questions, which might not correspond directly to a clinical diagnosis by a healthcare professional. Additionally, some PTSD items—such as ‘being constantly on guard, watchful, or easily startled’—may partly reflect housing instability, which could contribute to the observed association.
Despite these limitations, we believe that our study can bring valuable insights for policy. Public interventions might, for instance, consider prioritizing undocumented immigrants originating from countries with high levels of violence, as they may face elevated risks of PTSD. Administrative services may, likewise, require special attention, as undocumented immigrants applying for asylum are often obliged to tell their stories, a process that can reactivate traumatic memories. Additionally, previous studies relying on the same representative survey have documented limited access to both healthcare services and health insurance among undocumented immigrants, [43, 44]. Because of this underuse of healthcare services, policy interventions could be more effective in addressing other health determinants, such as access to the formal labor market or to improve living conditions. This could result, for example, in the opening of certain labor market segments to undocumented immigrants with temporary working visas in France. This is likely to be a promise step, as were initiatives like the Deferred Action for Childhood Arrivals (DACA) in the U.S., which have improved mental health and health insurance coverage of undocumented immigrants [45]. Finally, improving access to health and administrative services through dedicated assistance centers would also be another possible public intervention. Future research is nevertheless needed to address the full spectrum of factors shaping undocumented immigrants’ mental health and wellbeing.
Statements
Data availability statement
The data supporting the findings of this study are not publicly available due to confidentiality and legal restrictions. Access to the data is restricted, and they cannot be shared publicly.
Ethics statement
The survey was conducted in compliance with data privacy regulations under the supervision of the National Commission for Data Protection and Liberties (Commission Nationale de l'Informatique et des Libertés, CNIL), declaration MR004, registration number 2203002 v0.
Author contributions
CP conceived the original idea and wrote a first version of the manuscript. VL performed the the first part of the modelisation and conducted the literature review. AM performed the second part of the modelisation and wrote a second version of the manuscript. SG performed the data collection process. FJ supervised the project and discussed the results. JW supervised the project and discussed the results. PD performed a third version of the manuscript and supervised the project. All authors contributed to the article and approved the submitted version.
Funding
The author(s) declared that financial support was received for this work and/or its publication. The research project was supported by the Regional Health Agency (RHA) of Nouvelle-Aquitaine, the Fondation des Amis de Médecins du Monde (2016–2019), and the French National Research Agency (Agence Nationale de la Recherche, ANR), following calls for proposals in 2016.
Conflict of interest
The authors declare that they do not have any conflicts of interest.
Generative AI statement
The author(s) declared that generative AI was used in the creation of this manuscript. We relied on an AI-based tool to proofread the English in our article.
Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.
Supplementary material
The Supplementary Material for this article can be found online at: https://www.ssph-journal.org/articles/10.3389/ijph.2026.1608844/full#supplementary-material
References
1.
Eurostat (2025). Eurostat. Available online at: https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Enforcement_of_immigration_legislation_statistics#Source_data_for_tables_and_graphs (Accessed November 3, 2025).
2.
European Commission (2019). EMN Glossary: Irregular Migration. Brussels: European Commission. Available online at: https://ec.europa.eu/assets/home/emn-glossary/glossary.html?classification=4.2.1&detail=irregular+migration (Accessed November 3, 2025).
3.
AnderssonLMHjernAAscherH. Undocumented Adult Migrants in Sweden: Mental Health and Associated Factors. BMC Public Health (2018) 18:1–9. 10.1186/s12889-018-6294-8
4.
BoffaJWStanleyIHHomMANorrAMJoinerTESchmidtNB. PTSD Symptoms and Suicidal Thoughts and Behaviors Among Firefighters. J Psychiatric Research (2017) 84:277–83. 10.1016/j.jpsychires.2016.10.014
5.
AuxemeryY. Vers Une Nouvelle Nosographie Des Troubles Psychiques Post-Traumatiques: Intérêts Et Limites. Eur J Trauma and Dissociation (2019) 3(4):245–56. 10.1016/j.ejtd.2019.02.002
6.
KuehneAHuschkeSBullingerM. Subjective Health of Undocumented Migrants in Germany–a Mixed Methods Approach. BMC Public Health (2015) 15:1–12. 10.1186/s12889-015-2268-2
7.
SteelJLDunlavyACHardingCETheorellT. The Psychological Consequences of Pre-Emigration Trauma and Post-Migration Stress in Refugees and Immigrants from Africa. J Immigrant Minority Health (2017) 19:523–32. 10.1007/s10903-016-0478-z
8.
JournetFMestreCRemarkFSaglio-YatzimirskyMCVeïsseAWolmarkL. Protéger La Santé Psychique Et Reconnaître L’Exceptionnelle Gravité Des Psychotraumatismes. In: Actualité Et Dossiers En Santé Publique (2020). p. 111.
9.
PattenSBSchopflocherD. Longitudinal Epidemiology of Major Depression as Assessed by the Brief Patient Health Questionnaire (PHQ-9). Compr Psychiatry (2009) 50(1):26–33. 10.1016/j.comppsych.2008.05.012
10.
FazelMWheelerJDaneshJ. Prevalence of Serious Mental Disorder in 7000 Refugees Resettled in Western Countries: A Systematic Review. The Lancet (2005) 365(9467):1309–14. 10.1016/S0140-6736(05)61027-6
11.
PorterMHaslamN. Predisplacement and Postdisplacement Factors Associated with Mental Health of Refugees and Internally Displaced Persons: A Meta-Analysis. Jama (2005) 294(5):602–12. 10.1001/jama.294.5.602
12.
WenKMcGrathMAcarturkCIlkkursunZFuhrDCSondorpEet alPost-Traumatic Growth and Its Predictors Among Syrian Refugees in Istanbul: A Mental Health Population Survey. J Migration Health (2020) 1:100010. 10.1016/j.jmh.2020.100010
13.
NaimoMMassagliADegortesDFavaroACampagnolaNVidottoG. The Psychometric and Psychosocial Dimension of Albanian Immigration: Data from a Preliminary Study. G Ital Med Lav Ergon (2006) 28:104–10.
14.
SchoeversMAVan den MuijsenberghMETCLagro-JanssenAL. Self-Rated Health and Health Problems of Undocumented Immigrant Women in the Netherlands: A Descriptive Study. J Public Health Policy (2009) 30:409–22. 10.1057/jphp.2009.32
15.
HeerenMWittmannLEhlertUSchnyderUMaierTMüllerJ. Psychopathology and Resident status–comparing Asylum Seekers, Refugees, Illegal Migrants, Labor Migrants, and Residents. Compr Psychiatry (2014) 55(4):818–25. 10.1016/j.comppsych.2014.02.003
16.
MyhrvoldTSmåstuenMC. The Mental Healthcare Needs of Undocumented Migrants: An Exploratory Analysis of Psychological Distress and Living Conditions Among Undocumented Migrants in Norway. J Clinical Nursing (2017) 26(5-6):825–39. 10.1111/jocn.13670
17.
AngelettiSCeccarelliGBazzardiRFogolariMVitaSAntonelliFet alMigrants Rescued on the Mediterranean Sea Route: Nutritional, Psychological Status and Infectious Disease Control. The J Infect Developing Countries (2020) 14(05):454–62. 10.3855/jidc.11918
18.
SousaEAgudelo-SuárezABenavidesFGSchenkerMGarcíaAMBenachJet alImmigration, Work and Health in Spain: The Influence of Legal Status and Employment Contract on Reported Health Indicators. Int Journal Public Health (2010) 55:443–51. 10.1007/s00038-010-0141-8
19.
TeunissenETsaparasASaridakiATrigoniMvan Weel-BaumgartenEvan WeelCet alReporting Mental Health Problems of Undocumented Migrants in Greece: A Qualitative Exploration. Eur J Gen Pract (2016) 22(2):119–25. 10.3109/13814788.2015.1136283
20.
MartinFSashidharanSP. The Mental Health of Adult Irregular Migrants to Europe: A Systematic Review. J Immigrant Minor Health (2023) 25(2):427–35. 10.1007/s10903-022-01379-9
21.
BoisguerinBHauryB. Les Bénéficiaires De L'Ame En Contact Avec Le Système De Soins. In: Études Et Résultats (2008).645
22.
Médecins du Monde. Observatoire Européen De L’Accès Aux Soins De Médecins Du Monde: Rapport De L’Enquête (2008).
23.
DourgnonPGuillaumeSJusotFWittwerJ. In: Etudier L’Accés À L’Aide Médicale De L’État (AME) Des Personnes Sans Titre De Séjour. L’Enquête Premiers Pas. Question DEconomie De La Santé N° 244 (2019).
24.
PrinsABovinMJSmolenskiDJMarxBPKimerlingRJenkins-GuarnieriMAet alThe Primary Care PTSD Screen for DSM-5 (PC-PTSD-5): Development and Evaluation Within a Veteran Primary Care Sample. J General Internal Medicine (2016) 31(10):1206–11. 10.1007/s11606-016-3703-5
25.
SaundersJBAaslandOGBaborTFDe la FuenteJRGrantMDevelopment of the alcohol use disorders identification test (AUDIT): WHO collaborative project on early detection of persons with harmful alcohol consumption‐II. Addiction, 88(6), 791-804. Addiction (1993) 86 (6):791–804.
26.
BushKKivlahanDRMcDonellMBFihnSDBradleyKA. The AUDIT Alcohol Consumption Questions (AUDIT-C): An Effective Brief Screening Test for Problem Drinking. Ambulatory Care Quality Improvement Project (ACQUIP). Alcohol Use Disorders Identification Test. Arch Intern Med (1998) 158(16):1789–95. 10.1001/archinte.158.16.1789
27.
VaivaGJehelLCottencinODucrocqFDuchetCOmnesCet alPrévalence Des Troubles Psychotraumatiques En France Métropolitaine. L’encéphale (2008) 34(6):577–83. 10.1016/j.encep.2007.11.006
28.
Darves-BornozJMAlonsoJde GirolamoGGraafRDHaroJMKovess- MasfetyVet alMain Traumatic Events in Europe: PTSD in the European Study of the Epidemiology of Mental Disorders Survey. J Traumatic Stress (2008) 21(5):455–62. 10.1002/jts.20357
29.
AragonaMPucciDMazzettiMMaisanoBGeraciS. Traumatic Events, Post-Migration Living Difficulties and Post-Traumatic Symptoms in First Generation Immigrants: A Primary Care Study. Annali dell’Istituto superiore di sanita (2013) 49:169–75. 10.4415/ANN_13_02_08
30.
PopraweM. On the Relationship Between Corruption and Migration: Empirical Evidence from a Gravity Model of Migration. Public Choice (2015) 163:337–54. 10.1007/s11127-015-0255-x
31.
JamesPBRenzahoAMMwanriLMillerIWardleJGatwiriKet alThe Prevalence of Anxiety, Depression, and Post-Traumatic Stress Disorder Among African Migrants: A Systematic Review and Meta-Analysis. Psychiatry Research (2022) 317:114899. 10.1016/j.psychres.2022.114899
32.
BerniniABossavieLSanchezDGMakovecM. Corruption as a Push and Pull Factor of Migration Flows: Evidence From European Countries. Empirica (2024) 51:263–281. 10.1007/s10663-023-09600-0
33.
BahTLBatistaCGubertFMcKenzieD. Can Information and Alternatives to Irregular Migration Reduce “Backway” Migration from the Gambia?J Development Econ (2023) 165:103153. 10.1016/j.jdeveco.2023.103153
34.
JusotFSilvaJDourgnonPSermetC. Inégalités De Santé Liées À L'Immigration En France. Revue Économique (2009) 60(2):385–411.
35.
MoullanYJusotF. Why Is the ‘Healthy Immigrant Effect’Different Between European Countries?The Eur J Public Health (2014) 24(Suppl. l_1):80–6. 10.1093/eurpub/cku112
36.
KhlatMLegleyeSBricardD. Migration-Related Changes in Smoking Among Non-Western Immigrants in France. Eur Journal Public Health (2019) 29(3):453–7. 10.1093/eurpub/cky230
37.
KhlatMLegleyeSBricardD. Gender Patterns in Immigrants’ Health Profiles in France: Tobacco, Alcohol, Obesity and Self-Reported Health. Int J Environ Res Public Health (2020) 17(23):8759. 10.3390/ijerph17238759
38.
DustmannCFasaniFMengXMinaleL. Risk Attitudes and Household Migration Decisions. J Hum Resour (2023) 58(1):112–45. 10.3368/jhr.58.3.1019-10513r1
39.
GoldbachCSchlüterA. Risk aversion, time preferences, and out-migration. Experimental evidence from Ghana and Indonesia. J Econ Behav Organ, 150:132–48. 10.1016/j.jebo.2018.04.013
40.
AndersonLRMellorJM. Predicting Health Behaviors with an Experimental Measure of Risk Preference. J Health Economics (2008) 27(5):1260–74. 10.1016/j.jhealeco.2008.05.011
41.
GalizziMMMiraldoM. Are You what You Eat? Healthy Behaviour and Risk Preferences. The BE J Econ Anal and Policy (2017) 17(1):20160081. 10.1515/bejeap-2016-0081
42.
Cobb-ClarkDADahmannSCKettlewellN. Depression, Risk Preferences, and Risk-Taking Behavior. J Hum Resour (2022) 57(5):1566–604. 10.3368/jhr.58.1.0419-10183r1
43.
DourgnonPJusotFMarsaudonASarhiriJWittwerJ. Just a Question of Time? Explaining Non-Take-Up of a Public Health Insurance Program Designed for Undocumented Immigrants Living in France. Health Econ Policy L (2023) 18(1):32–48. 10.1017/S1744133122000159
44.
MarsaudonAJusotFWittwerJDourgnonP. Patients like Any Others? Providing Coverage to Undocumented Migrants in France: Effects on Access to Care and Usual Source of Care. Eur J Public Health (2024) 34(6):1157–62. 10.1093/eurpub/ckae143
45.
GiuntellaOLonskyJ. The Effects of DACA on Health Insurance, Access to Care, and Health Outcomes. J Health Econ (2020) 72:102320. 10.1016/j.jhealeco.2020.102320
Summary
Keywords
France, mental health, migration, posttraumatic stress disorder, undocumented immigrants
Citation
Prieur C, Lhote V, Marsaudon A, Guillaume S, Jusot F, Wittwer J and Dourgnon P (2026) Post-Traumatic Stress Disorder Among Undocumented Immigrants. Evidence for the Premier-Pas Survey. Int. J. Public Health 71:1608844. doi: 10.3389/ijph.2026.1608844
Received
28 June 2025
Revised
24 February 2026
Accepted
13 March 2026
Published
15 April 2026
Volume
71 - 2026
Edited by
J. M. Pescarini, University of London, United Kingdom
Reviewed by
Kathryn Mackey, London School of Hygiene and Tropical Medicine, United Kingdom
Two reviewers who chose to remain anonymous
Updates
Copyright
© 2026 Prieur, Lhote, Marsaudon, Guillaume, Jusot, Wittwer and Dourgnon.
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Antoine Marsaudon, marsaudon@irdes.fr
This Original Article is part of the IJPH Special Issue “The Health of Displaced People: A Challenge for Epidemiology and Public Health”
Disclaimer
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.