Brexit in 2016 hit the UK with crucial implications on people’s mental health, especially those who belong to ethnic minority backgrounds. But was there an earlier event in the UK that could have foreshadowed similar effects on individuals?
Yes! The announcement of the ‘hostile environment’ policies in 2012.
The process started with then-Home Secretary Theresa May’s desire “to create here in Britain a really hostile environment for illegal migration”. This led to the passage of the 2014 and 2016 Immigration Acts. This is where the study that we’re summarising in this blog (Dotsikas et al, 2024) becomes relevant. The researchers looked at the impacts of these Acts by comparing people from ethnic minority backgrounds with White British people using a UK Household Longitudinal Survey.
Hostile environment policies originated from an attempt to prevent illegal immigration into the UK. Further, the government’s aim was to identify those who might have already made it to the UK through illegal means. However, in order to do this, various agencies, such as landlords or employers, were given immigration control, where they would be held responsible if they were to employ or rent accommodation to someone that they have reason to believe might be residing or working in the UK illegally.
In efforts to make sure the Immigration Act 2016 was handled with precision, these authorities started to demonstrate structural racism, whether it be through not renting to ‘foreign-looking’ people, carrying out discriminatory checks, employing restrictions based on ethnicity and so forth.
In response, and building on previous work, a group of researchers from UCL, Sorbonne Université, University of New South Wales, and Camden and Islington NHS Foundation Trust came together to see how individuals’ mental health might have been affected by comparing the pre-policy (2009-2012); transition (2012-2016); and ongoing policy (2016-2020) periods. Findings suggest psychological distress increased among Pakistani and Bangladeshi people following the introduction of the policies, whereas Caribbean people showed a small decrease across policy eras, and levels remained stable in the White British group. Thus the hypothesis predicting an increase in psychological distress over the study period, particularly in minoritised ethnic groups was rejected.

The UK’s ‘hostile environment’ policies was believed to possibly cause harm to the mental health of individuals of ethnic minority.
Methods
The researchers used data collected on the national survey ‘Understanding Society: UK Household Longitudinal Survey (UKHLS)’. To understand the impact of the legislation on mental health and psychological distress, they compared the general health questionnaire (GHQ-12) scores for people from Black Caribbean, Black African,Indian, Bangladeshi, Pakistani, and White British backgrounds.
The GHQ is a self-rated questionnaire which measures outcomes like depression, anxiety, and sleep disturbance. Higher GHQ scores indicate greater psychological distress.
The researchers looked at mean GHQ scores for each ethnic group over three time periods:
- Pre-policy era (2009-2012): Before the policy was implemented.
- Transition era (2012-2016): When the policy changes that aimed to increase social exclusion for undocumented migrants started being put in place.
- Ongoing policy era (2016-2020): After the policy has been established.
Data from 42,968 participants were included in this study, with 35,918 White British participants and between 1132-1,905 participants for the other ethnic groups.
Results
In the pre-policy era, Pakistani and Bangladeshi people had the highest average psychological distress scores, while Indian and White British individuals had the lowest.
The mean GHQ score of Bangladeshi and Caribbean individuals increased in the transition era, then slightly decreased in the ongoing policy era. In contrast, the GHQ scores of African and Indian individuals decreased in the transition era before slightly increasing in the following period. In the end, their average scores were lower than the scores of White British people which remained stable across eras.
Finally, the mean GHQ scores of Pakistani people increased over the transition and ongoing policy era.

The highest impact of hostile policies was noticed among Pakistani and Bangladeshi groups.
Conclusions
Contrary to expectations, there was no overall significant effect of the ‘hostile environment’ policy on psychological distress across the ethnic groups included in the study. The GHQ scores of different ethnic groups followed distinct patterns of variation across policy periods.
This highlights the importance of considering ethnic groups as distinct entities. Indeed, even when exposed to the same stressor (the policy), the mental health of people from different backgrounds will be impacted differently.

The study found no overall significant effect of the ‘hostile environment’ policy on psychological distress across the ethnic groups.
Strengths and limitations
Strengths of this study include that the 12-item General Health Questionnaire (GHQ) is a multi-dimensional measure of mental health. This questionnaire is also widely validated as it has been extensively studied and has shown strong reliability and generalisability. However, even though the GHQ has been validated across different cultures and also has a more detailed assessment of psychological distress, the GHQ as an outcome measure is not sensitive to changes over time while the Kessler Psychological Distress scale is.
Furthermore, missing data on key variables like psychological distress can affect the validity of the results. Additionally, if the characteristics of the participants who dropped out are different from the ones who remained, this can affect the generalisability of the findings. Since the missing data was from certain groups, i.e., it was not random, there could have been an overestimation or underestimation of the effects being studied.
Psychological distress was measured using self-reported questionnaires which are subjective and individual perceptions of distress can be influenced by one’s cultural and ethnic background. Cultural factors need to be considered as they can affect the potential bias in understanding the wording of statements.
Although the analysis methods were extensive, this study does not consider intersectionality as the analysis does not fully account for factors such as gender, age, class, or immigration status interacting with ethnicity, which can lead to different levels of vulnerability to hostile environment policies. Additionally, it may have been constructive if this study was supplemented with qualitative interviews from the aforementioned ethnic groups to understand if individual policies can have different impacts on mental health.

Self-reported distress can be shaped by cultural and ethnic perceptions—highlighting the need for culturally sensitive tools.
Implications for practice
Clear guidelines on policyholders’ responsibilities can be implemented to mitigate the psychological distress experienced. For example, establishing interdepartmental collaboration (public health, social services, immigration) to systematically track mental health impacts and make necessary policy adjustments. Or implementing a mental health impact assessment as part of policy design, ensuring future immigration policies undergo pre- and post-implementation evaluations.
Targeted support for affected communities may need to be put in place as a result of this study. Mental health support group leaders and healthcare providers should be trained to detect policy-driven psychological distress. This could be achieved by developing NHS training programmes to help recognise symptoms of policy-driven psychological distress (e.g., anxiety linked to immigration uncertainty), implementing culturally adapted intervention strategies to better support minoritised communities, and introducing voluntary mental health screenings in high-risk populations to ensure early intervention.

Interdepartmental collaboration between public health, social services and immigration could help track the impact of policies on all citizen’s wellbeing.
Statement of interests
No conflicts of interest to declare.
Contributors
Thanks to the UCL Mental Health MSc students who wrote this blog from Drini Student Group: Christina Tzenios, Alia Galal, Saba Ghouri, Joel Barnett, Alaine Fernandes, Yipeng Zhang, Yalan Wang, Katharina Zankel and Hilal Karaduman.
UCL MSc in Mental Health Studies
This blog has been written by a group of students on the Clinical Mental Health Sciences MSc at University College London. A full list of blogs by UCL MSc students can be found here.
We regularly publish blogs written by individual students or groups of students studying at universities that subscribe to the National Elf Service. Contact us if you’d like to find out more about how this could work for your university.
Links
Primary paper
Dotsikas, K., McGrath, M., Osborn, D.P.J. et al. (2024) Exploring the impact of ‘hostile environment’ policies on psychological distress of ethnic groups in the UK: a differences-in-differences analysis. Soc Psychiatry Psychiatr Epidemiol (2024). https://doi.org/10.1007/s00127-024-02705-2