The city of Flint is the urban centre of Genesee County, Michigan, USA with a population of over 95,000 according to 2018 estimates (United States Census Bureau, 2019). On 25th April 2014, Flint changed its municipal water supply source from Lake Huron to the Flint River as a cost-saving measure (Adams, 2014) . However, the Flint River water was not treated with corrosion control chemicals to ensure the more acidic river water did not cause corrosion of water distribution pipes. By summer 2014, Flint residents had begun reporting changes in the smell, taste and appearance of their water as well as health effects such as skin rashes and hair loss.
However, officials insisted the water was safe and dismissed the idea of a link between water quality and health problems, and residents continued to use tap water. Meanwhile, the supply pipes continued corroding, leaching lead into the water (Kennedy, 2016) .
In September 2015, water experts discovered very high levels of lead in the tap water of some Flint homes (Flint Water Study, 2015) , and a local paediatrician found increases in children's blood lead levels corresponding with the time of the switch in water sources (Hanna-Attisha et al., 2016) . Finally, the state re-evaluated its water-testing data, discovering elevated levels of contaminants including bacteria and lead in Flint's drinking water, and concluded that the water was, in fact, unsafe (Kennedy, 2016) . Although the water source was switched back to the Lake Huron source in October 2015, a state of emergency was declared at both the state and federal level in January 2016 which was in effect until August 2016. Despite the state of emergency having been lifted, according to media reports many residents remain fearful of Flint's water, feel they have not received any explanation for why the crisis was allowed to happen and still lack trust in public health officials (Renwick, 2019) .
Naturally, the crisis has raised concerns about the physical health of Flint residents. Lead exposure can lead to high blood pressure, heart disease, damage to the brain and kidneys, and infertility (Agency for Toxic Substances and Disease Registry, 2007) . Lead exposure is particularly harmful for children, putting them at greater risk of brain and nervous system damage, slowed development and behavioural problems (Grandjean & Landrigan, 2014) . In addition to physical health concerns, there are also potential mental health consequences of the crisis which cannot be overlooked. Previous research suggests that experiencing a disaster or public health emergency -particularly one that is human-induced -can lead to mental health disorders and substantial negative effects on levels of stress (Makwana, 2019) . Psychological . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 3, 2020. . https://doi.org/10.1101/2020.05.30.20117952 doi: medRxiv preprint 3 consequences can occur not only during and in the short-term aftermath of a disaster or crisis but can also affect both adults and children for years after (Bland et al., 1996; Bolton et al., 2000) .
Residents of Flint may be particularly at risk of adverse mental health consequences due to the city's long-standing social and economic vulnerabilities: almost half of Flint's residents live below the federal poverty level (United States Census Bureau, 2019) and Flint has consistently been rated one of the most violent cities in the US (Harris, 2010; Warner et al., 2013) . Flint also has a long history of racial segregation, with environmental racism believed to be a contributor to the water crisis (Michigan Civil Rights Commission, 2017) . Disadvantaged communities are more likely to be vulnerable to adverse mental health outcomes after a disaster or emergency and have more barriers to treatment (SAMHSA, 2017) so the mental health of Flint residents is of particular concern.
Despite the risk to Flint residents in terms of their mental health, the psychological impact of the crisis has received little attention in the literature, and human-focused recovery efforts have been minimal in comparison to the recovery of physical infrastructure (Kruger et al., 2017a) . But the mental health impact from the Flint Water Crisis may be a long-lasting legacy for generations to come in the community, as has been seen in other post-disaster communities: for example, the fallout of the Chernobyl Nuclear Power Plant in Pripyat, Ukraine led to gaps in providing mental health care and research to disaster-affected communities since 1986, and this mental health impact has been labelled as the largest public health problem caused by the accident (The Chernobyl Forum, 2006) . In fact, the media have frequently compared the Flint situation with the Chernobyl disaster (Al-Sibai, 2019; McFarland, 2019) , while researchers have labelled the Flint Water Crisis more 'insidious' than Chernobyl (Campbell et al., 2016) , which causes concern as to the potential long-lasting impact of the crisis. Past disasters in other communities have shown the importance of resilience, which includes the ability to return to self-sufficiency and sustain relatively stable psychological and physical functioning after a traumatic event (Abir et al., 2016) , which highlights the importance of considering the level of resilience in Flint's community and how this can be improved. It is important that the psychological consequences of the crisis are not overlooked -particularly now, with the ongoing coronavirus (COVID-19) pandemic. Flint has the highest number of COVID-19 cases in Genesee County: as of 04 May 2020, Flint had recorded 644 cases (representing 39.5% of Genesee County cases), followed by Flint Township with 125 (7.6% of Genesee County's cases) (Genesee County Health Department, 2020) . The psychological consequences of the unprecedented lockdown of communities in order to reduce transmission is likely to be substantial (Brooks et al., 2020) and may be particularly so for . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 3, . . https://doi.org/10.1101 communities which have yet to fully recover from a past crisis and are now faced with another one. Taking account of the lessons learned from the fallout from the Chernobyl disaster and with   the current situation with the COVID-19 pandemic, applying best practices are important for   responding and serving the affected populations. This paper aimed to systematically review the published literature on the psychological impact of the Flint water crisis, specifically focusing on i) what is the mental health impact of the crisis?
and ii) what are the factors associated with this impact?
On 27 th March 2020, the following search strategy was used to search titles and abstracts in five databases (Medline, PsycInfo, Embase, Global Health and Web of Science) from inception to 2020 
To be included in the review, studies had to: i) include primary data; ii) be published in peerreviewed journals; iii) be written in English; and iv) report on either the psychological consequences of the Flint water crisis or factors associated with psychological outcomes as a result of the crisis.
One author (SKB) ran the search strategy on all databases and downloaded resulting citations to EndNote version X9 (Thomson Reuters, New York, USA) where duplicates were automatically . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 3, . . https://doi.org/10.1101 removed. The same author then screened all titles for relevance to the review, excluding any which were clearly not relevant. This was followed by screening of abstracts. The full texts of all citations still remaining were obtained and screened for relevance against the inclusion criteria.
Finally, the reference lists of included papers were hand-searched for additional relevant studies.
A spreadsheet was designed in order to systematically extract data from the literature. The following data was extracted: year of study, design and measures used, number of participants, demographic information of participants, and key results. Data extraction was carried out by one author (SKB). Thematic analysis (Braun & Clarke, 2006) was used to synthesise the data by coding it and organising it into themes.
Database searches yielded 216 articles. After 84 duplicates were removed, 132 articles remained for screening. Title screening removed 101 of these; abstract screening removed another 15; and 16 full texts were reviewed. Five were excluded, leaving eleven included in the review (Figure I). Table I summarises the design and participant information for each study and Table II summarises the evidence for each of the themes found in the literature. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
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The copyright holder for this preprint this version posted June 3, 2020. . https://doi.org/10.1101/2020.05.30.20117952 doi: medRxiv preprint 8 water-related resource needs.
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The copyright holder for this preprint this version posted June 3, . . https://doi.org/10.1101 Cuthbertson et al. (2016) Respondents believed the water crisis was increasing stress, anxiety and to a lesser extent depression among the city's population, and residents had been left feeling angry, defeated and on edge.
Participants believed that effects of stress were not limited to Flint residents and had a contagion effect: even those not directly affected were reported to feel stressed because they knew people affected by it. Among households aged 21+, 49.1% reported more anxiety or stress than usual, 46.8% more sleep problems than usual, 42.3% more of a depressed mood than usual and 33.3% more trouble concentrating than usual. Of households with a member aged under 21, 53.3% reported at least one behavioural concern more than usual: 37.3% reported more problems sleeping, 36.6% reported more aggressiveness, 35.7% reported more trouble concentrating and 33.5% reported more anxiety or stress than usual.
37.0% reported having a physical illness or injury for 14+ days in the last 30 days -significantly higher than the 12.6% reported in the 2014 BRFSS. 37.7% reported poor mental health for 14+ days in last 30 days, significantly higher than 12.9% in 2014 BRFSS. Almost 29% reported that poor physical/mental health limited their usual activities for 14+ days in last 30 days, significantly higher than 8.7% in 2014
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60% of those exposed to water with elevated lead levels reported the crisis had 'very much' affected their, or their children's, lives. Almost 40% of parents reported changes in their children's health and 65% reported changes in their own health.
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Perceived tap water quality predicted PTSD symptomatology and positive screening criteria for PTSD, independent of socio-demographics. 20% met the screening criteria for PTSD. Limiting the sample to those known for certain to be Flint residents (n=268) reduced statistical power; although the relationship between reported water quality and level of PTSD symptomatology remained significant, there were no longer any significant predictors of positive screens for PTSD. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
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20.0% of participants reported increased substance use.
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The copyright holder for this preprint this version posted June 3, 2020. Kruger (2018) Water quality experiences predicted general tendencies for future planning. Those who experienced poorer quality tap water demonstrated less future-focused time orientations and higher rates of risktaking behaviour.
Poorer water quality experiences directly predicted higher likelihoods of being a tobacco smoker.
Poor water quality was also associated with higher self-reported HIV risk, higher likelihood of being involved in a physical fight and less healthy diet. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 3, 2020. or social media) and 10.2% reported no trust in the government.
Half of households felt overlooked by decision-makers; of the 25.8% of households which reported 'a lot of' stress, 49.6% said it was related to feeling overlooked. Gray et al. (2017) Participants reported decreased trust in officials.
Kruger (2018) Those who experienced worse tap water quality had lower perceptions of police procedural justice (i.e.
whether or not police are fair and trustworthy) and lower intentions to co-operate with police.
Flint residents' trust in the local government was much lower than Michiganders' overall levels of trust: 11.3% of Flint residents reported trusting the local government, compared to around 80% in Michigan overall. Levels of trust in local governments in Flint were significantly lower (p<0.001) than the nationwide level of trust reported in 1972. Trust in state government was also low: 7.4% for Flint residents, compared to around 70% of Michiganders in general, and significantly lower than 1972 levels (p<0.001). This lack of trust in the local government predicted the extent to which participants considered leaving the city (p=0.021), while lack of trust in state government was not a significant predictor. 13.3% believed that removing local elected officials could restore trust in the government, 10.9% believed more honesty from elected officials could restore trust, 7.7% felt that improving transparency and communication with residents could restore trust and 9.9% believed trust could be restored by fixing the water situation. However, 7.9% did not know how trust could be restored, and 10.9% felt nothing could be done to restore it.
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The copyright holder for this preprint this version posted June 3, 2020. Singer et al. (2017) The Governor's pro-business administration and loss of local agency in decision-making were believed to be causes of the crisis. Several participants suggested that Flint residents would not be able trust the city again.
Media Cuthbertson et al. (2016) Stress was related to news coverage finding high levels of lead in the blood of Flint children.
The increase in attention from the media was reported as causing an increase in stress as many interpreted it as an indicator that something much worse was unfolding, something over which they had no power.
Living with uncertainty Cuthbertson et al. (2016) Stress was created by lack of knowledge about where to find lead testing for children.
Stress was also created by the potential permanent physical health effects of lead exposure, and participants identified anxiety as increasing due to the uncertainty of knowing if they had been exposed to lead as well as the unknown severity of effects of lead exposure (which they believed would be unknown for some time). Sneed et al. (2020) There was a slight decrease between 2016-2018 in the percentage of participants feeling the crisis would never be fixed; this was not statistically significant.
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75% of those exposed to water with elevated lead levels reported additional monthly expenses as a result, mostly due to buying bottled water (53%), water filters (36%) or gasoline to pick up water safety supplies (62%), as well as doctor appointments (20%) and gasoline to drive to these appointments (34%). .
It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
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The copyright holder for this preprint this version posted June 3, 2020. suggested that a long-term monitoring plan for children exposed to lead was necessary, along with the development of family support programs in schools.
Coping strategies Heard-Garris et al.
Participants reported positive coping mechanisms (active coping, 80%; venting, 99%; positive reframing, 72%; planning, 79%; humour, 44%; distraction, 73%; emotional support seeking, 65%;
advice-seeking, 99%; acceptance, 93%; and turning to religion or faith, 74%) and negative coping mechanisms (substance use, 20%; self-blame, 42%; disengagement, 51%; and denial, 59%).
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Participants directly affected by the water crisis reported symptoms of poor mental health in general (Kruger et al., 2017b) , post-traumatic stress disorder (Kruger et al., 2017a) , depression (Fortenberry et al., 2018) , anxiety or stress (Fortenberry et al., 2018; Gray et al., 2017; , sleep problems (Fortenberry et al., 2018; Kruger et al., 2018c) , fear , aggressiveness (Fortenberry et al., 2018) , trouble concentrating (Fortenberry et al., 2018) , emotional outbursts (Fortenberry et al., 2018) , decreased appetite (Fortenberry et al., 2018) , and exacerbation of pre-existing health conditions . Cuthbertson et al.'s (2016) expert panellists believed the water crisis was increasing stress, anxiety and to a lesser extent depression among Flint's population, and that residents had been left feeling angry, defeated and on edge. They also believed that effects of stress were not limited to Flint residents and that those outside of Flint could also be stressed due to knowing people affected by the crisis.
A study comparing indicators of psychological wellbeing in Flint after the water crisis with similar indicators in Michigan before the crisis (Fortenberry et al., 2018) found higher negative quality of life indicators in Flint after the crisis than in both 2012 and 2014, as well as significantly higher poor mental health and a significantly higher number of people reporting that physical or mental health had limited their usual activities than in 2013-2015.
More positively, Sneed et al.'s (2020) study showed some improvements in health outcomes over the years post-crisis: for adults aged 21 and over, aggressiveness, depressed mood, emotional outbursts, and anxiety/stress were lower in 2018 than they were in 2016, and for those aged under 21, there were significant declines in aggressiveness, emotional outbursts and problems in school.
However, there were no significant changes in reports of trouble concentrating, decreased appetite or sleep problems for those aged 21 and over; or sleep problems, decreased appetite, depressed mood or anxiety/stress for those under 21.
Kruger (2018) found that those who experienced poorer quality tap water demonstrated higher rates of risk-taking behaviour: in particular, poorer water quality experiences were associated with higher likelihood of tobacco smoking, higher self-reported HIV risk, higher likelihood of being involved in a physical fight and less healthy diet. Increased substance use was also noted by Heard-Gariss et al. (2017) and increased use of nicotine products by Fortenberry et al. (2018) . Sneed et al. (2020) found no significant decrease in substance use over the years after the crisis, 2016-2018. Cuthbertson et al.'s (2016) participants believed that the mental health effects of the . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 3, 2020. . https://doi.org/10.1101/2020.05.30.20117952 doi: medRxiv preprint 2 0 crisis could spill over into other areas of behavioural health, and could increase abuse, alcohol misuse, illicit drug use and prescription drug misuse.
Respondents in Cuthbertson et al.'s (2016) study felt that the entire community would be affected by the stress of the crisis, but particularly those in low-income African-American populations. Kruger et al. (2017a) found that younger age and fewer years of continuous education were associated with higher PTSD symptoms and likelihood of screening positive for PTSD. (2019) and Singer et al. (2017) . This decrease in trust may be due to feeling overlooked by decision-makers (Fortenberry et al., 2018) .
In terms of what could be done to restore trust in the government, Morckel and Terzano's (2019) participants suggested removing local elected officials, more honesty from elected officials, improving transparency and communication with residents, and fixing the water situation. Worryingly, 7.9% of participants in this study did not know how trust could be restored, and 10.9% felt nothing could be done to restore it.
Stress was related to news coverage finding high levels of lead in the blood of Flint children (Cuthbertson et al., 2016) . In the same study, the increase in attention from the media was reported as causing an increase in stress as many interpreted it as an indicator that something much worse was unfolding, something over which they had no power.
Participants cited various sources of uncertainty leading to stress: lack of knowledge about where to find lead testing for children in order to assess the potential impact of the crisis on their children (Cuthbertson et al., 2016) ; uncertainty of knowing if they had been exposed to lead as well as the unknown severity of effects of lead exposure (Cuthbertson et al., 2016) ; feeling that . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 3, 2020. .
the crisis was not over and would never be fixed (Fortenberry et al., 2018; Singer et al., 2017) ;
and uncertainty of the long-term effects of the crisis Singer et al., 2017) . Sneed et al. (2020) found a slight decrease between 2016-2018 in the percentage of participants feeling the crisis would never be fixed; however, this was not statistically significant.
Participants frequently reported financial concerns and hardships (Cuthbertson et al., 2016; Fortenberry et al., 2018; Gray et al., 2017; Heard-Garris et al., 2017; Singer et al., 2017) .
Financial concerns appeared to be higher in Flint residents after the crisis than previously reported in Michigan in 2012 and 2014 (Fortenberry et al., 2018) . These increased concerns were due to Flint residents paying extremely high water bills for unusable water (Cuthbertson et al., 2016) ; decreased property values (Cuthbertson et al., 2016; Gray et al., 2017; Singer et al., 2017) ; lacking funds to relocate (Cuthbertson et al., 2016) ; decreases in the local economy (Cuthbertson et al., 2016; Gray et al., 2017) ; decreases in tourism ; and additional monthly expenses such as buying bottled water and water filters, doctor appointments, and buying gasoline to travel to appointments or to pick up water safety supplies (Heard-Garris et al., 2017). Sneed et al.'s (2020) study showed no significant change in financial concern in the years postcrisis, 2016-2018.
The panellists in Cuthbertson et al.'s (2016) study reported a sense of divide between Flint residents and other communities, suggesting others were trying to distance themselves from Flint. 
In Fortenberry et al.'s (2018) study, over 60% of participants reported fear regarding drinking or cooking with filtered tap water, and over half reported 'a lot of' fear around bathing and brushing teeth with unfiltered tap water. As a result of the water crisis, more than three quarters had reduced their water usage in some way, including decreased duration and frequency of baths and showers and changing bathing methods altogether, for example using baby wipes or hand sanitiser for washing. Morckel and Terzano's (2019) participants also reported low trust in water . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 3, 2020. . https://doi.org/10.1101/2020.05.30.20117952 doi: medRxiv preprint 2 2 safety, which was a significant predictor of considering leaving the city (p<0.001). Sneed et al. (2020) found that fears related to drinking and cooking with tap water did not significantly decrease between 2016-2018; however, there were much larger decreases in fears of bathing and brushing teeth.
Difficulties seeking help Fortenberry et al. (2018) found that only approximately half of those participants who felt they needed help for behavioural health concerns actually sought help. They reported barriers to seeking help such as finding it difficult to trust in the healthcare system or healthcare providers; finding services too expensive; having no transportation; being disabled or housebound; concerns about what others would think; and lack of health insurance. Gray et al.'s (2017) participants believed the crisis had led to decreases in educational attainment, and reported concerns about educational attainment and delinquency in Flint's youth in the years to come. Participants suggested that a long-term monitoring plan for children exposed to lead was necessary, along with the development of family support programs in schools.
The majority of Heard-Garris et al.'s (2017) participants reported using positive coping mechanisms such as active coping, venting, positive reframing, planning, humour, distraction, emotional support seeking, advice-seeking, acceptance, and turning to religion or faith. Negative coping mechanisms such as denial and disengagement were also reported by more than half of the participants, and over 40% reported self-blame.
The negative effects caused by the water crisis on Flint's residents have created a variety of issues in the affected population. Studies found in this review suggest various degrees of anxiety, depression, post-traumatic stress, sleep problems and worries about physical health existing in the affected population. Additionally, fear, negative coping strategies such as smoking and alcohol misuse, and risky health behaviours were prominent findings as response reactions from those affected by the crisis. These negative consequences were exacerbated by lowered trust in public health and government officials, heightened uncertainty about the long-term impacts of the crisis and the appropriate course of action to resolve emerging issues, and increased amount of financial hardships caused by the crisis. Self-perceived stigma from others in the community and . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 3, . . https://doi.org/10.1101 at-large population along with difficulties seeking help were beliefs found in this review to prevent those affected to improve their respective situation. This review also found evidence that concerns and doubt about the tap water in Flint, Michigan continued even after the state of emergency was lifted.
However, there are some positive implications from this review, as the major stressors identified can be targeted with interventions and consequently their impact lessened. For example, negative coping strategies such as smoking and alcohol misuse and risky health behaviours can be addressed in the Flint community through public health interventions and programs. Programs that enable peer and group support have been effective in establishing and enabling changes in these behaviors (Ford et al., 2013; Tracy & Wallace, 2016) . Additionally, in a longitudinal study of the first three years after the crisis, improvements in mental health outcomes as well as a decline in fears of using tap water for bathing and brushing teeth were seen, which suggest public health messages surrounding water usage for these purposes were well-received (Sneed et al., 2020) . However, other concerns related to the crisis remain unchanged, such as financial worries and an overall concern that the crisis will never be fixed. Use of evidence-informed interventions can reduce these concerns, enhance wellbeing, and improve functioning for affected individuals (Morganstein & Ursano, 2020) . Despite progression in some beliefs, community efforts to reduce psychological distress are still warranted.
The psychological consequences of the Flint water crisis may generalise to other disasters, and support findings from similar incidents involving environmental contamination based on past disasters. For example, studies that examining the long-term mental health consequences of the Chernobyl nuclear power plant disaster show the affected populations developed an exaggerated sense of presumed exposure and danger due to Chernobyl over time, which fuelled an increased level of anxiety and perpetual stigmatization through the generations (Bromet et al., 2011; Havenaar et al., 2016; Samet & Patel, 2011 . Besides similar results found in this review with impact on mental health and stigmatization, the themes of distrust in government officials and risky behaviours were also seen among populations affected by Chernobyl (Bolt et al., 2018; Samet & Patel, 2013) . There were more depression, anxiety, and overall concerns specifically about children's well-being among the affected populations even decades after the incident -this brings heightened urgency for further investigations and longitudinal studies related to the Flint Water Crisis to ensure something similar does not happen in Flint.
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The copyright holder for this preprint this version posted June 3, 2020. Additionally, the COVID-19 pandemic creates a possible compound effect to those affected by the Flint Water Crisis, as they now face coping with another emergency while still recovering from another. Despite being over three years since the incident, the communities, as seen in this review, are still reeling from the mental health impact which will be exposed further with the pandemic. Although coronavirus infects people regardless of income, the low-income communities in Michigan have been deeply affected with a higher number of cases than highincome ones, especially in Genesee County (Genesee County Health Department, 2020) . This highlights the issue of how Michigan is segregated by income and race, with Flint a good representative of this in the state (Muhammad et al., 2018; Pulido, 2016) , with race a crucial factor in the high caseload of confirmed COVID-19 patients in Flint (Fonger, 2020) .
There are several implications for policy and practice based on the findings of this review. First, rebuilding trust in official communication and science within the Flint community will enhance ongoing efforts to resolve the widening gaps that were caused by the initial crisis. Local government and public health officials need to ensure they regain the trust of residents along with engaging and involving the Flint community and its members in recovery efforts. For example, ensuring transparency, seeking community input, and enabling two-way communication with the public on resolving issues will allow trust to be built institutionally. Having government and public health officials being held accountable, demonstrating integrity by admitting to mistakes, and seeking input from respected outside experts will bridge their past leadership woes and connect with the communities they are serving (Boufides et al., 2019) .
In Flint, efforts are being made to provide urgent mental health services. Psychological first aid training for people interested in helping others cope with the water emergency has been provided by the Flint Community Resilience Group (Cuthbertson et al., 2016) and the Flint RECAST program educates residents about trauma (Ahmad, 2019) . However, there remain concerns about whether enough is being done and also whether people would actually seek psychological help (Goodnough & Atkinson, 2016) . Still, mental health services need to be readily available and ramped up in the Flint community. Government and public health officials should identify and strengthen resources for mental health services for affected residents, and conduct follow-up mental health assessments to evaluate change over time. Additional mental health interventions should also occur in Flint, especially to include the current COVID-19 pandemic. However, economic factors, such as access and costs, need to be considered when implementing mental health interventions. An increase of educational media campaigns and handouts can also enhance the mental health interventions by emphasising the potential long-term mental health implications . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 3, 2020. . https://doi.org/10.1101/2020.05.30.20117952 doi: medRxiv preprint 2 5 of the crisis, providing contact information for support groups and readily available mental health services. All trust-building and mental health services done in the Flint community will build infrastructure and enhance the efforts if future crises arise.
Future research in Flint should go beyond the profound societal effects caused by the crisis and create opportunities to resolve the disadvantages for the Flint community to become an example of a community that can bounce back and be resilient from future public health emergencies.
Despite the concept of community resilience having been variously defined by researchers, government officials and public health practitioners without a unifying meaning, several themes found across the definitions align with the results found in this review and help to prioritize future research (Patel et al., 2017) . Community participatory research examining crisis communication, leadership and resources can help build trust and evidence-based infrastructure and working relationships between officials and Flint community members. With a compound effect of the current impact caused by the COVID-19 pandemic, maladaptive coping strategies and risky health behaviours may need urgent attention to manage the distressing emotions and community memory of compounded crises (Morganstein & Ursano, 2020) . Facing multiple public health emergencies can cause inherent challenges and trust for communities but amplifying the evidence-based interventions and mental health research can not only address the current public health emergencies but can also help prevent a bigger distress caused by future ones as well.
The majority of studies reviewed were cross-sectional and thus suggest associations, rather than causality; very few studies were longitudinal, so the long-term effects of the Flint Water Crisis are unclear. Much of the included research was conducted while the crisis was ongoing: the full impact of the crisis may therefore be under-estimated, due to the speed with which data was collected; conversely, the mental health consequences could be overestimated as Sneed et al.'s (2020) findings suggest that symptoms may improve over time.
The majority of studies did not compare rates of mental health problems between Flint and other populations, or pre-Water Crisis rates in Flint, making it difficult to truly ascertain the impact of the crisis on mental health. Other factors, such as the economic recession or personal circumstances, could also have affected mental health. Additionally, much of the data in the included papers was obtained via self-reports, which may not necessarily be reliable. In terms of the review process itself, the main limitation is that screening and data extraction was done by only one author: the review could be improved by a second author . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 3, 2020. carrying out the same process to ensure consistency. Secondly, the decision to include only peer-reviewed literature and not grey literature may mean that the data reviewed in this article is subject to publication bias.
Literature on the impact of the Flint Water Crisis suggests considerable psychological consequences to Flint residents, exacerbated by mistrust in officials and financial difficulties.
While Flint struggles to recover from this crisis, the city has also seen a much higher rate of COVID-19 than other parts of Genesee County, meaning Flint residents now have two disasters to cope with. Our review highlights the urgent need for more mental health resources for the people of Flint.
. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 3, 2020. . https://doi.org/10.1101/2020.05.30.20117952 doi: medRxiv preprint . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 3, . . https://doi.org/10.1101 