Study characteristics

Studies included were published between 1998 and 2024, with varied designs (see Supplementary Table 1 available at https://doi.org/10.1192/bjp.2025.10385): mixed methods (n = 1), cross-sectional (n = 21), longitudinal (n = 8), randomised control trial data (n = 1), secondary data analysis (n = 1) and qualitative studies (n = 6). The research spanned multiple countries: Australia (n = 10), Austria (n = 3), Germany (n = 4), Israel (n = 2), Jordan (n = 1), Norway (n = 1), Serbia (n = 1), Sweden (n = 1), Switzerland (n = 2), Turkey (n = 2), Uganda (n = 1), UK (n = 2), USA (n = 7) and a European collection of countries (n = 1). In total, 15 394 participants were included, representing diverse populations. Samples involved displaced populations who were Congolese (n = 1), Vietnamese (n = 2), Syrian (n = 4), Somali (n = 1), Eritrean (n = 2) Afghan (n = 5), Cambodian (n = 2), Bosnian (n = 1), Yugoslavian (n = 1) and of mixed nationalities (n = 19). Reasons for leaving their homes and specific traumatic events included: war and/or conflict (n = 2), persecution under oppressive systems targeting LGBTQIA + individuals (n = 1), violence and abuse (n = 1), a lack of basic needs (n = 1), being close to death (n = 1), individual (n = 1), family (n = 1) and collective trauma (n = 1), trafficking/torture (n = 3), separated and not separated from family (n = 1), genocide (n = 1), and others reported traumatic events more generally (n = 24).

Risk of bias

We carefully evaluated all papers for potential bias, using the MMAT for 37 papers and AACODS for one non-peer-reviewed paper (see Appendix B in the Supplementary material). The risk of bias highlights some key areas where the findings should be interpreted with caution. Many quantitative studies clearly defined their inclusion and exclusion criteria, but ten papers lacked clarity in this regard or failed to report these details. Thirty-three papers acknowledged the limited generalisability of their findings. This limitation was often due to the use of convenience or snowball sampling methods, or a focus on specific target populations – such as individuals who were from a particular country, highly educated, technology proficient or married. One research team conducted a structural equation model, while acknowledging their study did not have sufficient statistical power. Two other papers did not provide information on the validity of their measurement tools. Meanwhile, five papers had incomplete outcome data, or it was difficult to determine their completeness, although all papers did control for confounders. One descriptive paper appeared to be at risk for non-response bias.

All qualitative research studies showed minimal bias, while the sole mixed-methods paper fell short of certain criteria. It lacked a clear rationale for using mixed methods and failed to effectively integrate both quantitative and qualitative results. Lastly, the one grey literature paper³⁶ reviewed met all the AACODS grading criteria.

Themes

Five key social functioning themes arose out of the literature, these were: post-migration living difficulties, everyday functioning, acculturation and integration, social relationships, and employment and education (see Supplementary Table 1).

Post-migration living difficulties

Eight studies reported on the impact of trauma on post-displacement living difficulties (PMLDs), i.e. learning a new language, loneliness, discrimination and access to support).^{Reference Silove, Sinnerbrink, Field, Manicavasagar and Steel37} The research consistently linked PTSD and traumatic experiences to heightened PMLDs.^{Reference Schick, Zumwald, Knöpfli, Nickerson, Bryant and Schnyder38–Reference Byrow, Liddell, O’Donnell, Mau, McMahon and Bryant44} Specifically, trauma significantly predicted worries about the future, including visa insecurity and emergency return concerns.^{Reference Liddell, Byrow, O’Donnell, Mau, Batch and McMahon45} A latent class analysis (LCA) provided support for this result, showing that individuals facing severe PMLDs had experienced more traumatic events than those in moderate or low-PMLD groups.^{Reference Byrow, Liddell, O’Donnell, Mau, McMahon and Bryant44} Only one study found no association between the total number of traumatic events and the total number of PMLDs.^{Reference Spaaij, Schick, Bryant, Schnyder, Znoj and Nickerson46,Reference Williamson, Murphy, Katona, Curry, Weldon and Greenberg47}

Everyday functioning

Five studies explored how trauma affects everyday functioning, with mixed results. Ainamani et al^{Reference Ainamani, Elbert, Olema and Hecker21} identified a significant positive correlation between PTSD and psychosocial dysfunction. Qualitative data highlighted several underlying mechanisms, including shame-induced low mood leading to self-neglect, post-trauma physical health challenges and a progressively negative self-perception.^{Reference Baumgartner, Renner, Wochele-Thoma, Wehle, Barbui and Purgato48} Other studies failed to find a relationship between traumatic experiences and daily functioning^{Reference Byrow, Nickerson, Specker, Bryant, O’Donnell and McMahon49,Reference Slewa-Younan, Yaser, Guajardo, Mannan, Smith and Mond50} or between trauma and help-seeking.^{Reference Tartakovsky and Saranga51}

Acculturation and integration

Evidence of the impact of trauma on integration and acculturation in a host country was mixed. Nine studies demonstrated negative effects on integration. Trauma severity correlated with increased acculturation difficulties.^{Reference Nicholson and Walters26} Trauma was further associated with reduced sociocultural adaptation,^{Reference Kurt, Acar, Ilkkursun, Yurtbakan, Acar and Uygun52} as well as diminished ethnic and host cultural orientation and adoption,^{Reference Kartal, Alkemade, Eisenbruch and Kissane19,Reference Starck, Gutermann, Schouler-Ocak, Jesuthasan, Bongard and Stangier53,Reference Jorgenson and Nilsson54} and reduced cultural competency.^{Reference Teodorescu, Heir, Hauff, Wentzel-Larsen and Lien55} This relationship can be mediated by emotion-focused coping,^{Reference Starck, Gutermann, Schouler-Ocak, Jesuthasan, Bongard and Stangier53} negative contacts with host country civilians^{Reference Kurt, Acar, Ilkkursun, Yurtbakan, Acar and Uygun52} and acculturative stress.^{Reference Jorgenson and Nilsson54} Individuals with PTSD symptoms showed similar patterns – with reduced social integration^{Reference Schiess-Jokanovic, Knefel, Kantor, Weindl, Schäfer and Lueger-Schuster56} and difficulties with language acquisition in those with complex PTSD cluster.^{Reference Kurt, Ekhtiari, Ventevogel, Ersahin, Ilkkursun and Akbiyik57}

However, recent studies revealed more nuanced relationships between trauma and integration. Using structural equation modelling, Kurt et al^{Reference Kurt, Ekhtiari, Ventevogel, Ersahin, Ilkkursun and Akbiyik57} found that traumatic events negatively predict heritage culture maintenance while positively predicting destination culture adoption, even though initial bivariate correlations had suggested no relationship with host culture adoption.;^{Reference Baumgartner, Renner, Wochele-Thoma, Wehle, Barbui and Purgato48} Limited effects were observed in relation to trauma on societal participation, except when individuals experienced violence and abuse, which significantly impaired participation.^{Reference Birman and Tran58}

Conversely, eight studies reported minimal or no effects of trauma on acculturation outcomes. Traumatic events were found to have no association with acculturation,^{Reference Teodorescu, Heir, Hauff, Wentzel-Larsen and Lien55,Reference Nakash, Nagar, Shoshani and Lurie59} integration in Norwegian culture^{Reference Teodorescu, Heir, Hauff, Wentzel-Larsen and Lien55} and orientation toward host or origin culture,^{Reference Jorgenson and Nilsson54} nor did they predict cultural identity or English language competency.^{Reference Teodorescu, Heir, Hauff, Wentzel-Larsen and Lien55} While Hunkler and Khourshed^{Reference Hunkler and Khourshed60} reported an effect of traumatic events on cognitive-cultural integration, this effect was not significant. Regarding community engagement, PTSD symptoms at a first measurement timepoint did not predict later engagement.^{Reference Nickerson, Liddell, Keegan, Edwards, Felmingham and Forbes61} Additionally, no differences were observed in socioeconomic conditions, discrimination, family concerns or residence insecurity in those with complex PTSD compared with those with standard PTSD.^{Reference Kurt, Ekhtiari, Ventevogel, Ersahin, Ilkkursun and Akbiyik57}

Social relationships

Eighteen studies presented mixed findings in relation to the impact of trauma on social relationships, with the majority of studies reporting a negative effect of trauma on positive social relationships. In one study, over 70% of participants with PTSD reported social withdrawal and inactivity.^{Reference Schiess-Jokanovic, Gösling-Steirer, Kantor, Knefel, Weindl and Lueger-Schuster27} Additionally, in an LCA, participants allocated to a social disconnection group had experienced a greater variety of traumatic events compared with other groups (i.e. fear of immigration, low/moderate difficulties classes).^{Reference Byrow, Liddell, O’Donnell, Mau, McMahon and Bryant44} Trauma was linked with weaker social networks^{Reference Schiess-Jokanovic, Knefel, Kantor, Weindl, Schäfer and Lueger-Schuster56} and predicted fewer contacts with the host society, through the impact on mental health symptoms.^{Reference Birman and Tran58} Trauma further predicted more post-migration living difficulties related to isolation and loneliness, predicting subsequent depression, PTSD and disability.^{Reference Liddell, Byrow, O’Donnell, Mau, Batch and McMahon43} Increased post-traumatic cognitions were associated with less social connectedness,^{Reference Dolezal, Alsubaie, Sheikh, Rosencrans, Walker and Zoellner62} although more traumatised individuals still yearned for social contact.^{Reference Kivling-Bodén and Sundbom63} Eritrean participants further reported the negative impacts of trauma on relationships with both fellow Eritreans and Israelis.^{Reference Kurt, Acar, Ilkkursun, Yurtbakan, Acar and Uygun52}

The role of mistrust, leading to isolation and strained relationships was highlighted in the qualitative research.^{Reference Baumgartner, Renner, Wochele-Thoma, Wehle, Barbui and Purgato48,Reference Jankovic-Rankovic, Oka, Meyer, Snodgrass, Eick and Gettler64,Reference Rizkalla, Alsamman, Bakr, Masud, Sbini and Segal65} Specifically, trafficking survivors reported that their perpetrators were often friends which compounded the loss of trust.^{Reference Baumgartner, Renner, Wochele-Thoma, Wehle, Barbui and Purgato48} Others felt shame about their traumatic experiences, contributing to their isolation. Additionally, challenges in sharing their experiences arose due to a lack of empathy or understanding from others.^{Reference Rizkalla, Alsamman, Bakr, Masud, Sbini and Segal65} Injuries from torture caused shame in social settings while trauma-induced insomnia made social interactions more difficult. Other difficulties that arose as a result of the trauma included fear of commitment, heightened aggression and obsessive behaviours – all of which influenced their relationships with others.^{Reference Rizkalla, Alsamman, Bakr, Masud, Sbini and Segal65}

Our analysis indicated that trauma has a negative impact on family relationships. Over 50% of refugees and asylum seekers reported avoiding social contact due to unfulfilled family expectations following experiences of trauma.^{Reference Schiess-Jokanovic, Gösling-Steirer, Kantor, Knefel, Weindl and Lueger-Schuster27} Participants identifying as LGBTQIA+ distanced themselves from family members, viewing their family as part of the oppressive system.^{Reference Attia, Das, Tang, Li and Qiu66} Some respondents hesitated to share their experiences, both to protect their loved ones from hearing about their torture and out of fear of criticism.^{Reference Rizkalla, Alsamman, Bakr, Masud, Sbini and Segal65} In some cases, family members held participants responsible for their detention, contributing to a fractured relationship.^{Reference Rizkalla, Alsamman, Bakr, Masud, Sbini and Segal65} Traumatic events also predicted more worries for family members in their home country or in detention,^{Reference Liddell, Byrow, O’Donnell, Mau, Batch and McMahon43} and others felt family life was unachievable.^{Reference Baumgartner, Renner, Wochele-Thoma, Wehle, Barbui and Purgato48}

Nevertheless, some positive outcomes of trauma exposure were also reported, including greater family unity, stronger emotional bonds and enhanced interpersonal understanding.^{Reference Rizkalla, Alsamman, Bakr, Masud, Sbini and Segal65} Those who were survivors of a genocide found the trauma increased their compassion, with a greater sense of interconnectedness.^{Reference Uy and Okubo28} The positive effect of experiencing trauma extended to their family members where they had a new sense of appreciation. Other research found that trauma can have a positive impact on the support they received from their spouse.^{Reference Nakash, Nagar, Shoshani and Lurie59} This positive effect extended past family connections with analyses showing that group membership was 1.08 times higher for each point increase in trauma exposure.^{Reference Slewa-Younan, Yaser, Guajardo, Mannan, Smith and Mond50}

Notably, however, three studies found no relationship between trauma and social engagement^{Reference Nickerson, Liddell, Keegan, Edwards, Felmingham and Forbes61,Reference Nickerson, Byrow, O’Donnell, Bryant, Mau and McMahon67} or social network size.^{Reference Schiess-Jokanovic, Knefel, Kantor, Weindl, Schäfer and Lueger-Schuster56} However, ongoing PTSD was associated with a weak social network.^{Reference Schiess-Jokanovic, Knefel, Kantor, Weindl, Schäfer and Lueger-Schuster56} Another study found that while traumatic events prior to resettlement were negatively associated with social support, adding trauma to their predictive model did not improve its explanatory power.^{Reference Jankovic-Rankovic, Oka, Meyer, Snodgrass, Eick and Gettler64}

Employment and education

Fifteen studies investigated the impact of trauma on employment or education. Although the majority of studies indicated the negative effects of trauma on employment, some results were mixed. In one study, over 50% described avoiding stressful situations such as searching for a job following rejection.^{Reference Schiess-Jokanovic, Gösling-Steirer, Kantor, Knefel, Weindl and Lueger-Schuster27} In addition, those experiencing PTSD often had lower employment opportunities^{Reference Dietrich, Estramiana, Luque and Reissner68} or trauma was associated with unemployment.^{Reference Schiess-Jokanovic, Knefel, Kantor, Weindl, Schäfer and Lueger-Schuster56,Reference Kivling-Bodén and Sundbom63} Participants expressed not feeling mentally well-enough to work,³⁶ and others felt they had lost hope and trauma had led to a negative view of the world, where employment did not seem possible.^{Reference Baumgartner, Renner, Wochele-Thoma, Wehle, Barbui and Purgato48}

When in work, task-oriented performance was affected in individuals suffering from PTSD (i.e. work that demonstrates problem solving, coping with stress and learning).^{Reference Stasielowicz69} Longitudinally, traumatic experiences negatively predicted employment status, labour income, labour force participation, permanent job status, skilled occupation, hours worked a week and work in agriculture.^{Reference Dang, Trinh and Verme70} Traumatic events additionally predicted economic post-migration living difficulties, which were then related to increased depressive symptoms.^{Reference Liddell, Byrow, O’Donnell, Mau, Batch and McMahon43} Additional results^{Reference Rizkalla, Alsamman, Bakr, Masud, Sbini and Segal65} supported the findings of negative impacts.^{Reference Rizkalla, Alsamman, Bakr, Masud, Sbini and Segal71} Trauma following torture led to difficulties in committing to work. For others, it motivated them to engage in activism for their home country, shifting priorities away from employment in the host country. However, in some cases post-traumatic growth is possible, with a direct effect on adaptive performance: handling stress and emergencies, creative problem-solving, interpersonal adaptability, coping with unpredictable work environments and learning new tasks.^{Reference Stasielowicz69} For instance, Cambodian leaders who were displaced in the USA used their trauma as a strength.^{Reference Uy and Okubo28} Participants felt that trauma shifted their priorities and goals, inspiring a new dedication to higher education or career advancement. Being in the USA provided additional opportunities, fostering a belief that nothing is impossible and giving participants a renewed sense of purpose. Some embraced new missions, pursuing meaning through political activism, community engagement or helping others. In trafficked survivors, trauma resulted in a drive to create a better future, with a focus on education and careers which help others.^{Reference Baumgartner, Renner, Wochele-Thoma, Wehle, Barbui and Purgato48} Despite this, five studies found that traumatic events had no effect on employment^{Reference Schweitzer, Melville, Steel and Lacherez40,Reference Teodorescu, Heir, Hauff, Wentzel-Larsen and Lien55,Reference Schiess-Jokanovic, Knefel, Kantor, Weindl, Schäfer and Lueger-Schuster56,Reference Hunkler and Khourshed60,Reference Dolezal, Alsubaie, Sheikh, Rosencrans, Walker and Zoellner62} or education.^{Reference Hunkler and Khourshed60,Reference Dolezal, Alsubaie, Sheikh, Rosencrans, Walker and Zoellner62}

Stratification by traumatic events

Eleven papers focused on specific traumatic events which can be grouped into interpersonal and war-based trauma.

Interpersonal trauma

Eight studies explored the impact of interpersonal trauma on social functioning, with many focusing specifically on the link with social relationships. Survivors of abuse, trafficking or torture experienced greater integration issues and impaired participation. Participation challenges were specifically related to a lack of engagement in community activities.^{Reference Byrow, Nickerson, Specker, Bryant, O’Donnell and McMahon49} Integration was further limited, measured by a subsection of the PMLD checklist encompassing difficulties around communication, social participation, access to services, everyday living and discrimination.^{Reference Schick, Zumwald, Knöpfli, Nickerson, Bryant and Schnyder38} Trauma resulted in isolation, loneliness and struggles with trust, shame, aggression and strained relationships.^{Reference Baumgartner, Renner, Wochele-Thoma, Wehle, Barbui and Purgato48,Reference Rizkalla, Alsamman, Bakr, Masud, Sbini and Segal65} LGBTQIA+ individuals viewed family as part of an oppressive system, affecting their relationships,^{Reference Scoglio, Reilly, Girouard, Quigley, Carnes and Kelly72} though some trauma survivors reported stronger family bonds and a greater emotional understanding.^{Reference Uy and Okubo28,Reference Rizkalla, Alsamman, Bakr, Masud, Sbini and Segal65}

Interpersonal trauma also affected additional areas of social functioning. Collective trauma symptoms were linked to post-migration difficulties,^{Reference Kirsch, Maleku, Kim, Aziz, Dada and Haran42} and family separation was associated with increased social, economic and future-related challenges.^{Reference Liddell, Byrow, O’Donnell, Mau, Batch and McMahon43} However, growth was evident in some, with a desire for educational and employment opportunities.^{Reference Baumgartner, Renner, Wochele-Thoma, Wehle, Barbui and Purgato48} Cambodian genocide survivors, for example, reshaped their life goals towards education, careers or activism, finding renewed purpose in the USA.^{Reference Uy and Okubo28} Having been close to death or experiencing a lack of basic needs was not related to participation.^{Reference Byrow, Nickerson, Specker, Bryant, O’Donnell and McMahon49}

War-based trauma

Three papers focused on conflict-based trauma. One study found that a model including gender, age and education predicted 7% of the variance in psychosocial dysfunction. However, when war- or conflict-related PTSD was added, the model’s predictive value increased to 48%.^{Reference Ainamani, Elbert, Olema and Hecker21} Higher levels of PTSD following war were also associated with greater self-reported integration difficulties,^{Reference Schick, Zumwald, Knöpfli, Nickerson, Bryant and Schnyder38} yet the experience of war-related trauma and probable PTSD symptoms did not predict help-seeking.^{Reference Tartakovsky and Saranga51}