A single nucleotide polymorphism (-250 A/C) of the GFAP gene is associated with brain structures and cerebral blood flow.

AIM: Glial fibrillary acidic protein (GFAP), the intermediate filament protein expressed in astrocytes, plays a key role in many aspects of brain function through communication with neurons or blood vessels. A common single nucleotide polymorphism (SNP), GFAP -250 C/A (rs2070935), is associated with the transcriptional regulation of GFAP, which can potentially result in the genotype-specific brain structure. This study aimed to verify the biological effects of the GFAP variants on brain structure and function. METHODS: We investigated the associations between the GFAP variants and magnetic resonance imaging findings, including gray and white matter volumes, white matter integrity, and resting arterial blood flow, from 1212 healthy Japanese subjects. RESULTS: The GFAP -250 C/A genotype was significantly associated with total gray matter volume, total white matter volume, average mean diffusivity, and mean cerebral blood flow. In voxel-by-voxel analyses, the GFAP genotype showed significant associations with the regional gray and white matter volumes in the inferior frontal lobe and corpus callosum, the regional mean diffusivity in the left posterior region, and the regional cerebral blood flow throughout the brain. CONCLUSION: This study revealed a common SNP that is significantly associated with multiple global brain structure parameters.

Longitudinal characteristics of resilience among adolescents: A high school student cohort study to assess the psychological impact of the Great East Japan Earthquake.

AIM: Resilience, the ability to cope with disasters and significant life adversity, is an important factor to consider when studying the mental health of populations affected by a disaster. Although high school students in a community affected by a disaster should have specific characteristics of resilience, little has been reported on the issue. This study was designed to provide initial data regarding characteristics of the resilience of high school students affected by a catastrophe. METHODS: A total of 760 high school students in Natori City, which was devastated by the Great East Japan Earthquake in 2011, were profiled, and a 3-year longitudinal study was conducted with 254 students who had entered the school in 2012. Resilience was evaluated with the 10-item Connor-Davidson Resilience Scale. The Quick Inventory of Depressive Symptomatology-Japanese version, the Zung Self-Rating Anxiety Scale, and the Impact of Event Scale-Revised were also administered to assess the students' mental health. RESULTS: Among the students who entered the high school in 2012, 28.6% showed high resilience, and the proportion increased to 42.9% in 2013 and 46.6% in 2014. The Quick Inventory of Depressive Symptomatology-Japanese version and Impact of Event Scale-Revised scores decreased significantly over the 3-year study period, but there were no significant differences in the Zung Self-Rating Anxiety Scale scores over time. CONCLUSION: This initial study profiling the characteristics of resilience among adolescents suggests that resilience is a highly changeable component of mental health among people who have faced adversity. Resilience can be a useful indicator of recovery from adversity and a target of interventions for improving mental health conditions.

Polymorphisms in the microglial marker molecule CX3CR1 affect the blood volume of the human brain.

AIM: CX3CR1, a G-protein-coupled receptor, is involved in various inflammatory processes. Two non-synonymous single nucleotide polymorphisms, V249I (rs3732379) and T280M (rs3732378), are located in the sixth and seventh transmembrane domains of the CX3CR1 protein, respectively. Previous studies have indicated significant associations between T280M and leukocyte functional characteristics, including adhesion, signaling, and chemotaxis, while the function of V249I is unclear. In the brain, microglia are the only proven and widely accepted CX3CR1-expressing cells. This study aimed to specify whether there were specific brain regions on which these two single nucleotide polymorphisms exert their biological impacts through their functional effects on microglia. METHODS: Associations between the single nucleotide polymorphisms and brain characteristics, including gray and white matter volumes, white matter integrity, resting arterial blood volume, and cerebral blood flow, were evaluated among 1300 healthy Japanese individuals. RESULTS: The major allele carriers (V249 and T280) were significantly associated with an increased total arterial blood volume of the whole brain, especially around the bilateral precuneus, left posterior cingulate cortex, and left posterior parietal cortex. There were no significant associations between the genotypes and other brain structural indicators. CONCLUSION: This finding suggests that the CX3CR1 variants may affect arterial structures in the brain, possibly via interactions between microglia and brain microvascular endothelial cells.

Microglial production of TNF-alpha is a key element of sustained fear memory.

The proinflammatory cytokine productions in the brain are altered in a process of fear memory formation, indicating a possibility that altered microglial function may contribute to fear memory formation. We aimed to investigate whether and how microglial function contributes to fear memory formation. Expression levels of M1- and M2-type microglial marker molecules in microglia isolated from each conditioned mice group were assessed by real-time PCR and immunohistochemistry. Levels of tumor necrosis factor (TNF)-α, but not of other proinflammatory cytokines produced by M1-type microglia, increased in microglia from mice representing retention of fear memory, and returned to basal levels in microglia from mice representing extinction of fear memory. Administration of inhibitors of TNF-α production facilitated extinction of fear memory. On the other hand, expression levels of M2-type microglia-specific cell adhesion molecules, CD206 and CD209, were decreased in microglia from mice representing retention of fear memory, and returned to basal levels in microglia from mice representing extinction of fear memory. Our findings indicate that microglial TNF-α is a key element of sustained fear memory and suggest that TNF-α inhibitors can be candidate molecules for mitigating posttraumatic reactions caused by persistent fear memory.

School-Based Interventions Aimed at the Prevention and Treatment of Adolescents Affected by the 2011 Great East Japan Earthquake: A Three-Year Longitudinal Study.

How natural disasters affect the psychological state of adolescents has not been well studied. Thus, we examined the effect of a natural disaster on high-school-aged youth and considered the most effective forms of support following such a disaster. We examined students from two high schools that were near the epicenter of the 9.0-magnitude Great East Japan Earthquake, which struck the Tohoku coastal area on March 11, 2011, causing severe damage to the region. The questionnaires measuring depression, anxiety, and post-traumatic stress reaction (PTSR) was administered to the students 3 times between July 2012 and August 2014; students who scored above the cut-off values of these measures were considered high-risk students. School teachers, nurses, and counselors provided a school-based intervention for all high-risk students identified in the survey. Data were analyzed using the Kruskal-Wallis H-test. Survey data revealed that 860 of the 1,432 (55.9%) high school students were at high risk of psychological trauma in 2012. This rate did not change substantially in the following 2 years, reaching 1,059 of 1,488 (69.1%) in 2013, and 949 of 1,430 (62.7%) in 2014. Depression and PTSR scores were significantly lower after the intervention (for 2nd and 3rd grade students in 2013 and 2014) compared to before (for the initial 2012 survey). However, there were no significant differences between the 1st grade students for all three years. Thus, school-based interventions involving psychological testing and interviews might reduce the rates of depression and PTSR in high school students.

Post-traumatic growth of children affected by the Great East Japan Earthquake and their attitudes to memorial services and media coverage.

AIMS: Post-traumatic growth (PTG) refers to positive changes that result from coping with a major life crisis or a traumatic event. Factors influencing PTG in youth have not been well characterized but could have a great impact on overall maturation. METHODS: Fourth to ninth graders (n = 3337) attending elementary or junior high schools located in a district severely damaged by the Great East Japan Earthquake completed a questionnaire, including the revised Posttraumatic Growth Inventory for Children (PTGI-C-R) along with the Post Traumatic Stress Symptoms for Children 15 items (PTSSC-15), 31 months after the event. Experience of the disaster, prior traumatic experiences, and attitudes toward memories of the disaster (rumination) were scored by their caregivers and teachers, and effects of these factors on PTG were evaluated. RESULTS: There were no significant associations between PTGI-C-R and sex or experiences of the disaster. However, PTGI-C-R was negatively correlated with age (r = -0.132, P < 0.001). There was significant but very weak negative correlation between PTGI-C-R and PTSSC-15 among the children (r = -0.096, P < 0.001). PTGI-C-R was significantly associated with positive attitudes to memorial services (P < 0.001) and media coverage (P < 0.05). CONCLUSION: Positive attitudes to deliberate rumination may facilitate PTG in children following natural disasters.

Therapeutic concentration of lithium stimulates complement C3 production in dendritic cells and microglia via GSK-3 inhibition.

Evidence indicates that widely prescribed mood stabilizer, lithium (Li), mediates cellular functions of differentiated monocytic cells, including microglial migration, monocyte-derived dendritic cell (MoDC) differentiation, and amelioration of monocytic malfunctions observed in neuropsychiatric diseases. Here, we surveyed molecules which take major roles in regulating these monocytic cellular functions. MoDCs treated with 1 and 5 mM Li, and microglia separated from Li-treated mice were subjected to microarray-based comprehensive gene expression analyses. Findings were validated using multiple experiments, including quantitative PCR, ELISA and immunostaining studies. Differing effects of Li on the two cell types were observed. Inflammation- and chemotaxis-relevant genes were significantly over-represented among Li-induced genes in MoDCs, whereas no specific category of genes was over-represented in microglia. The third component of complement (C3) was the only gene which was significantly induced by a therapeutic concentration of Li in both MoDCs and microglia. C3 production was increased by Li via GSK-3 inhibition. Li-induced C3 production was seen only in differentiated monocytic cells, but not in circulating monocytes. Our findings highlight a link between Li treatment and C3 production in differentiated monocytic cells, and reveal a regulatory role of GSK-3 in C3 production. Induction of microglial C3 production might be a novel neuroprotective mechanism of Li via regulating interactions between microglia and neurons. GLIA 2015;63:257-270.

Post-traumatic stress disorder and depression prevalence and associated risk factors among local disaster relief and reconstruction workers fourteen months after the Great East Japan Earthquake: a cross-sectional study.

BACKGROUND: Many local workers have been involved in rescue and reconstruction duties since the Great East Japan Earthquake (GEJE) on March 11, 2011. These workers continuously confront diverse stressors as both survivors and relief and reconstruction workers. However, little is known about the psychological sequelae among these workers. Thus, we assessed the prevalence of and personal/workplace risk factors for probable post-traumatic stress disorder (PTSD), probable depression, and high general psychological distress in this population. METHODS: Participants (N = 1294; overall response rate, 82.9%) were workers (firefighters, n = 327; local municipality workers, n = 610; hospital medical workers, n = 357) in coastal areas of Miyagi prefecture. The study was cross-sectional and conducted 14 months after the GEJE using a self-administered questionnaire which included the PTSD Checklist-Specific Version, the Patient Health Questionnaire-9, and the K6 scale. Significant risk factors from bivariate analysis, such as displacement, dead or missing family member(s), near-death experience, disaster related work, lack of communication, and lack of rest were considered potential factors in probable PTSD, probable depression, and high general psychological distress, and were entered into the multivariable logistic regression model. RESULTS: The prevalence of probable PTSD, probable depression, and high general psychological distress was higher among municipality (6.6%, 15.9%, and 14.9%, respectively) and medical (6.6%, 14.3%, and 14.5%, respectively) workers than among firefighters (1.6%, 3.8%, and 2.6%, respectively). Lack of rest was associated with increased risk of PTSD and depression in municipality and medical workers; lack of communication was linked to increased PTSD risk in medical workers and depression in municipality and medical workers; and involvement in disaster-related work was associated with increased PTSD and depression risk in municipality workers. CONCLUSIONS: The present results indicate that at 14 months after the GEJE, mental health consequences differed between occupations. High preparedness, early mental health interventions, and the return of ordinary working conditions might have contributed to the relative mental health resilience of the firefighters. Unlike the direct effects of disasters, workplace risk factors can be modified after disasters; thus, we should develop countermeasures to improve the working conditions of local disaster relief and reconstruction workers.

Life and mental health of medical students after the Great East Japan Earthquake.

Students of the Tohoku University School of Medicine experienced the Great East Japan Earthquake on March 11, 2011. We conducted a series of surveys to examine the relationships among their experiences and activities on the day of the earthquake, their physical, mental, and economic problems following the disaster, and how their problems changed over time. The initial survey was performed in April 2011, with three follow-up surveys in July 2011, February 2012, and April 2013. The initial survey focused on students' experiences and living conditions during the disaster, which contained questions on their locations and circumstances, family circumstances, lives after the earthquake, voluntary works, physical or mental health problems, and desire for counseling. The follow-up surveys included new items regarding their circumstances, changes in their health problems, and their desire for economic assistance. Students who answered the first survey to the 4th one, with response rates in the following bracket, were as follows: 472 (28.0%), 640 (29.9%), 681 (36.0%), and 678 (39.0%), respectively. Six months after the earthquake, about 20% having experienced physical and/or mental problems. Although there was a trend toward a reduction in suffering and health problems over time, some students' conditions remained unchanged or worsened. It is notable that students who had participated in voluntary activities, despite their own suffering of harm and distress, were identified as the group that required the closest attention. Our present results can be applied to appropriate supports for students in future large-scale disasters.

[Factors associated with the psychological impact of the Great East Japan earthquake on high school students 1 year and 4 months after the disaster].

The purpose of this study was to investigate factors associated with the psychological impact of the Great East Japan Earthquake on high school students 1 year and 4 months after the disaster, and clarify support needs of the students. In the outreach program for students of three high schools in coastal areas of southern Miyagi Prefecture, Japan, 1,973 students were surveyed after obtaining informed consent for participation. Questionnaires included: the Quick Inventory of Depressive Symptomatology (QIDS-J), Self-rating Anxiety Scale (SAS), Impact of Event Scale-revised (IES-R), and Connor-Davidson Resilience Scale (CD-RISC10). All scores were compared using SPSS 20.0 J between school grades, locations of the schools, and extent of damage due to the Great East Japan Earthquake. Our analysis showed a significant positive correlation between school grades and the level of anxiety. PTSR scores, but not anxiety nor depressive scores, of students whose lives have suffered extensive damage were significantly higher than those of students who have not. Students of high schools which have suffered extensive damage and use temporary buildings showed significantly higher levels of depression and anxiety, and significantly lower resilience, compared to students of high schools which were not damaged. Although previous findings demonstrated that younger children have a higher risk of being influenced by disasters, symptoms related to PTSR and depression were found frequently in the high school students as well. Among the high school students, our analysis showed a positive correlation between the level of anxiety and school grades, probably because the disaster has affected an influential and pivotal point in their lives.

[Activity to prevent mental diseases after the Great East Japan Earthquake].

Following the Great East Japan Earthquake, we have been supporting psychiatric hospitals and mental health and welfare centers in Miyagi Prefecture. In October 2011, with a grant from Miyagi Prefecture, the Department of Preventive Psychiatry was established in Tohoku University Graduate School of Medicine. The institute aims to promote the prevention of and early intervention for mental diseases. As its members, we carry out our duties in collaboration with the Miyagi Disaster Mental Health Care Center. We refer to our activities as the Great East Japan Earthquake Mental Health Support and Research (GEMS) project. The GEMS project includes both practices and research in the affected areas in Miyagi Prefecture. The focus is on supporting those who provide services for survivors long-term, such as municipal employees, nurses, fire fighters, and staff of the social welfare council. We investigated how much the disaster impaired the functioning of psychiatric hospitals and clinics in Miyagi Prefecture. We also conduct mental health surveys in public organizations. Based on the results, we arrange workshops, consultation, or counseling. Moreover, we promote improvement of the mental health skills of mental health professionals, which are essential for mid and long-term support after the disaster. One of them is "Skills for Psychological Recovery". As members of the support organization in the region, we keep working toward the recovery and development of mental health systems in Miyagi Prefecture.

Emotional processing during speech communication and positive symptoms in schizophrenia.

AIMS: The recognition of emotion is often impaired in patients with schizophrenia. The relationship of this deficit with symptoms of psychosis remains unclear. In the current study, we investigated the relationship between emotional processing and positive psychotic symptoms in schizophrenia. METHODS: Twenty-eight patients with schizophrenia and 37 healthy participants were included in the study. They were instructed to listen to a set of sentences and judge whether the emotional valence expressed verbally and that expressed by affective prosody were congruous or incongruous. RESULTS: Overall, the patients with schizophrenia had more inaccurate responses than the healthy participants and the poor performance was prominent when the patients processed affectively negative scenarios. The percentage of accurate responses negatively correlated with the severity of positive symptoms when the scenarios and/or the affective prosody had a negative valence. CONCLUSION: Patients with schizophrenia appear to have impaired function in the processing of negative verbal information. Impaired processing of negative verbal and prosodic information seems to be associated with positive symptoms in schizophrenia.

[Application of cognitive behavioral therapy to early phase of psychosis].

Attempts to apply cognitive-behavioral therapy (CBT) to treat patients in the early stage of psychosis, including those with First-Episode Psychosis (FEP) and those with an At-Risk Mental State (ARMS), have recently attracted considerable attention. Such CBT for FEP focuses on promoting the recovery process and relapse prevention, although evidence on its efficacy is currently limited. Further, studies on CBT for ARMS have not consistently demonstrated its effectiveness. Some reports affirm the effectiveness of CBT in FEP prevention, while others claim that the treatment leads to no compelling difference in comparison to nonspecific treatment such as supportive therapy and treatment as usual. It is evident that psychosocial interventions play a fundamental role in the treatment of early stages of psychosis. Therapeutic approaches based on CBT have been applied to various cases: however, further research is necessary in order to produce more concrete results and obtain the evidence needed to approve this method.

[Natori EI project: the early intervention project for psychiatric disorders by the Miyagi Psychiatric Center].

Attempts to promote early intervention (EI) for psychiatric disorders are becoming accepted worldwide. Although several attempts at EI have begun in Japan, this movement is still limited, and the development of concrete EI services suited to individual regions is required. At the Miyagi Psychiatric Center, the "Natori EI project" is being carried out with the aim of improving the mental health of young people. This project involves three activities: consultation and mental health promotion in high schools, specialized outpatient clinics for young people, and psychosocial intervention for first-episode psychosis. There are many difficulties in building a system to support this kind of EI within the framework of the conventional medical care system; it is necessary to sort out issues such as collaboration with government and educational institutions, sharing the basic principle of EI, medical economic problems, ensuring manpower, and staff training system.

[Challenges faced by psychiatric services in Miyagi Prefecture after the Great East Japan Earthquake].

Following the Great East Japan Earthquake and Tsunami, the number of patients with onset, relapse, and exacerbation of mental disorders was expected to increase in Miyagi Prefecture, one of the worst affected areas. The functioning of almost all psychiatric hospitals sharply declined or even ceased. This situation worsened with traffic congestion and crippled public transportation, hindering many patients with psychiatric disorders from accessing mental health services. Among them, patients with schizophrenia and related disorders were affected the most; some could not reach the hospitals and clinics they had regularly visited and had to become new patients of another hospital or clinic. Moreover, an increasing number of patients with schizophrenia needed to be hospitalized because of acute exacerbations of their disorder, due to the experience of the disaster and the consequent drastic changes in their living environment Unfortunately, the support system for psychiatric institutions after disasters is not yet well structured; the system needs to be rebuilt and strengthened in anticipation of future disasters.

[The Great East Japan earthquake and mid- and long-term prospect for mental health and welfare in Miyagi Prefecture].

About twenty-thousand persons were deceased or missing in the Great East Japan Earthquake on March 11, 2011. More than half of them belonged to Miyagi Prefecture. The entire coastal areas in Miyagi Prefecture fell victim to the disaster owing to tsunami damage. The damage in mental health system varied in areas both qualitatively and quantitatively ("patchy disparity"), to which uniform support cannot be applied. Such a disparity should be considered in the mid-and long-term prospect for mental health and welfare. The disaster exposed the fragility of the mental health and welfare in Japan as symbolized by 'depopulated' and 'immature' medical care system. The Tohoku University in the disaster area is actively engaged in the assistance for the various aspects of reconstruction.

Four mood stabilizers commonly induce FEZ1 expression in human astrocytes.

OBJECTIVES: Mood stabilizers influence the morphology, chemotaxis, and survival of neurons, which are considered to be related to the mood-stabilizing effects of these drugs. Although previous studies suggest glial abnormalities in patients with bipolar disorder and an effect of mood stabilizers on certain genes in astrocytes, less is known about the effects of mood stabilizers in astrocytes than in neurons. The present study identifies a common underlying response to mood stabilizers in astrocytes. METHODS: Human astrocyte-derived cells (U-87 MG) were treated with the four most commonly used mood stabilizers (lithium, valproic acid, carbamazepine, and lamotrigine) and subjected to microarray gene expression analyses. The most prominently regulated genes were validated by qRT-PCR and western blot analysis. The intercellular localization of one of these regulated genes, fasciculation and elongation protein zeta 1 (FEZ1), was evaluated by immunofluorescence staining. RESULTS: The microarray data indicated that FEZ1 was the only gene commonly induced by the four mood stabilizers in human astrocyte-derived cells. An independent experiment confirmed astrocytic FEZ1 induction at both the transcript and protein levels following mood stabilizer treatments. FEZ1 localized to the cytoplasm of transformed and primary astrocytes from the human adult brain. CONCLUSIONS: Our data suggest that FEZ1 may play important roles in human astrocytes, and that mood stabilizers might exert their cytoprotective and mood-stabilizing effects by inducing FEZ1 expression in astrocytes.

An association study on polymorphisms in the PEA15, ENTPD4, and GAS2L1 genes and schizophrenia.

Our previous study examined a number of methamphetamine (METH)/phencyclidine (PCP)-reactive tags in rat brain, using a serial analysis of gene expression. Among human homologous genes, which matched METH/PCP-reactive tags, three human genes were identified: phosphoprotein enriched in astrocyte 15 (PEA15), ectonucleoside triphosphate diphosphohydrolase 4 (ENTPD4), and growth arrest-specific 2 like 1 (GAS2L1), which are localized in the chromosome 1q21.1, 8p21.3, and 22q12.2, respectively. We postulated that these genes are plausible candidate genes that play a role in pathogenesis for schizophrenia. Using tagging single-nucleotide polymorphisms (SNPs), we performed a case-control comparison for three SNPs in the PEA15 gene, and six SNPs in the GAS2L1 gene in a sample set of subjects (240 schizophrenia patients and 286 control subjects). Twelve SNPs in the ENTPD4 gene were analyzed in a subset of subjects (94 schizophrenia patients and 94 control subjects). No single SNP displayed a significant difference regarding the allelic frequency or genotypic distribution between the affected cases and controls for any of the genes examined. There was neither a significant difference in the frequency of three marker haplotype in the PEA15 gene or of six marker haplotype in the GAS2L1 gene between the cases and controls. The present study fails to provide evidence for the contribution of PEA15, ENTPD4, and GAS2L1 genes to the etiology of schizophrenia in the Japanese population.

Physical and psychological outcome in long-term survivors of childhood malignant solid tumor in Japan.

PURPOSE: Few studies have assessed physical and psychological status in long-term survivors of childhood solid tumors in Japan. For children with such diseases diagnosed and treated in our hospital, our purpose was to clarify the physical and psychological status of long-term survivors and their parents. METHODS: Subjects were 56 patients who were diagnosed at our institution as having a childhood malignant solid tumor between 1982 and 2005 and had been alive for at least 5 years after treatment. Surveys were sent and returned by mail. RESULTS: Of the 56 patients surveyed, 32 responded. The current health condition and psychosocial status of survivors were evaluated as good by their parents. However, psychological tests revealed psychosocial problems in 28.1% of the children. Severe posttraumatic stress associated with the child's disease and its treatment was present in 15.6% of the parents. CONCLUSION: Physical status of long-term survivors of childhood malignant solid tumors was good in general. However, psychological tests revealed psychosocial problems in some of the children and posttraumatic stress in the parents. Considering the diversity of both the diseases and their clinical course, a qualitative study is warranted for further analysis.

Trajectories for Post-traumatic Stress Disorder Symptoms Among Local Disaster Recovery Workers Following the Great East Japan Earthquake: Group-based Trajectory Modeling.

BACKGROUND: As many local municipality and medical workers were involved in disaster recovery duties following the Great East Japan Earthquake (GEJE) on March 11, 2011, the aim of this work was to elucidate the distinct trajectories for post-traumatic stress disorder (PTSD) symptoms and associated factors among these personnel. They confronted a diverse range of stressors both as survivors and as relief workers; however, little is known about their longitudinal PTSD symptoms. METHODS: The participants were 745 local municipality and hospital medical workers [average age: 43.6 ± 9.5 years, range: 20 - 66 years; 306 (59%) women] involved in disaster recovery duties following the GEJE. PTSD symptoms were measured using the Japanese version of the PTSD Checklist Specific Version (PCL-S) at four time points: 14, 30, 43, and 54 months after the GEJE. Using group-based trajectory modeling, distinct trajectories were elucidated. RESULTS: We identified five distinct PTSD symptoms profiles: resistance (n = 467, 62.7%), subsyndromal (n = 181, 24.3%), recovery (n = 47, 6.3%), fluctuating (n = 26, 3.5%), and chronic (n = 24, 3.2%). The trajectories differed according to the post-disaster working conditions and personal disaster experiences. LIMITATIONS: Potential selection bias resulting from the limited number of participants who completed all waves. The survey was conducted in one region of the disaster area. CONCLUSIONS: The majority of participants remained stable, with a relatively small group classified as chronic and fluctuating. Our results highlight the importance of improved working conditions and sustained monitoring of workers responding to natural disasters.