Japanese public health nurses classified based on empathy and secondary traumatic stress: variable-centered and person-centered approaches.

BACKGROUND: Healthcare providers frequently help traumatized people and are regularly exposed to indirect trauma from their work, resulting in negative psychological responses, such as secondary traumatic stress. Empathy has been associated with patient's quality of care and secondary traumatic stress among healthcare providers. However, the relationship between dispositional empathy and secondary traumatic stress has not been fully elucidated. This study used person- and variable-centered approaches to explore the nature of this relationship. METHODS: A total of 1,006 Japanese public health nurses working in the Tohoku region and Saitama prefecture completed questionnaires that included scales assessing dispositional empathy, secondary traumatic stress, and burnout. First, we examined predictors of secondary traumatic stress using multiple linear regression analysis. Then, we conducted a latent profile analysis to classify participants into unique groups based on four subscales of dispositional empathy (i.e., empathic concern, perspective taking, personal distress, fantasy) and secondary traumatic stress. Finally, we compared the mean values of the study variables across these groups. RESULTS: The multiple regression indicated that in those working in Saitama prefecture, lifetime traumatic experiences, work-related distress, and personal distress were positively related to secondary traumatic stress, but perceived support was negatively related to secondary traumatic stress. Latent profile analysis extracted four unique subgroups. Group 1 displayed the highest secondary traumatic stress levels. Group 2 was characterized by the highest level of empathic concern, personal distress, and fantasy and the lowest perspective taking. Group 3 had a moderate secondary traumatic stress level. Group 4 had the lowest secondary traumatic stress and personal distress scores. In these four groups, the burnout scale (exhaustion, cynicism, and professional efficacy) showed a pattern similar to the secondary traumatic stress scale. CONCLUSIONS: Our person-centered approach showed that this sample of public health nurses could be classified into four unique groups based on their empathy and secondary traumatic stress scores. Although this group of public health nurses was not large, one group displayed high personal distress levels and high secondary traumatic stress levels. Further research is needed to determine effective interventions for this group.

Risk and resilience in trajectories of post-traumatic stress symptoms among first responders after the 2011 Great East Japan Earthquake: 7-year prospective cohort study.

BACKGROUND: First responders to disasters are at risk of developing post-traumatic stress disorder (PTSD). The trajectories of post-traumatic stress symptom severity differ among individuals, even if they are exposed to similar events. These trajectories have not yet been reported in non-Western first responders. AIMS: We aimed to explore post-traumatic stress symptom severity trajectories and their risk factors in first responders to the 2011 Great East Japan Earthquake (GEJE) - a historically large earthquake that resulted in a tsunami and a nuclear disaster. METHOD: A total of 55 632 Japan Ground Self-Defense Force (JGSDF) personnel dispatched to the GEJE were enrolled in this 7-year longitudinal cohort study. PTSD symptom severity was measured using the Impact of Event Scale-Revised. Trajectories were identified using latent growth mixture models (LGMM). Nine potential risk factors for the symptom severity trajectories were analysed using multinomial logistic regression. RESULTS: Five symptom severity trajectories were identified: 'resilient' (54.8%), 'recovery' (24.6%), 'incomplete recovery' (10.7%), 'late-onset' (5.7%), and 'chronic' (4.3%). The main risk factors for the four non-resilient trajectories were older age, personal disaster experiences and working conditions. These working conditions included duties involving body recovery or radiation exposure risk, longer deployment length, later or no post-deployment leave and longer post-deployment overtime. CONCLUSIONS: The majority of first responders to GEJE were resilient and developed few or no PTSD symptoms. A substantial minority experienced late-onset and chronic symptom severity trajectories. The identified risk factors can inform policies for prevention, early detection and intervention in individuals at risk of developing symptomatic trajectories.

Mental health consequences for survivors of the 2011 Fukushima nuclear disaster: a systematic review. Part 2: emotional and behavioral consequences.

To compile the findings of studies assessing emotional and behavioral changes in the survivors of the 2011 Fukushima nuclear disaster, we performed a systematic review in August 2019 using four literature databases (PubMed, PsycINFO, Psychology and Behavioral Sciences Collection, and ICHUSHI). Peer-reviewed manuscripts, either in English or Japanese, were included in the searches. Sixty-one studies were retrieved for the review. Of these, 41 studies (67.2%) assessed emotional consequences, 28 studies (45.9%) evaluated behavioral consequences, and 8 studies (13.1%) evaluated both emotional and behavioral outcomes. The main research topic in emotional change was radiation exposure-associated risk perception, as reported in 15 studies. This risk perception included immediate health effects (eg, acute radiation syndrome) as well as future health effects (eg, future cancer and genetic effects). Lowered subjective well-being was reported in eight studies. Six studies reported perceived discrimination/stigmatization in the disaster survivors. The most critical behavioral change was an increase in suicides compared with residents in the whole of Japan or affected by the earthquake and tsunami, but not by the nuclear disaster. Increased rate of alcohol and tobacco use was reported, although the effect on one's health was inconsistent. As a conclusion, the Fukushima nuclear disaster survivors suffered issues in risk perception, well-being, stigmatization, and alcohol/tobacco use in the first 8 years after the disaster. The present study is important in order to better understand the emotional and behavioral responses to future nuclear/radiological disasters as well as other "invisible" disasters, such as chemical and biological public health crises.

Mental health consequences for survivors of the 2011 Fukushima nuclear disaster: a systematic review. Part 1: psychological consequences.

To integrate scholastic literature regarding the prevalence and characteristics of the psychological consequences faced by survivors of the 2011 Fukushima earthquake/tsunami/nuclear disaster, we conducted a systematic review of survivor studies concerning the Fukushima disaster. In August 2019, four literature databases (PubMed, PsycINFO, Psychology and Behavioral Sciences Collection, and ICHUSHI) were used in the literature search. Peer-reviewed manuscripts reporting psychological consequences, either in English or Japanese, were selected. A total of 79 studies were selected for the review. Twenty-four studies (30.4%) were conducted as part of the Fukushima Health Management Survey-large-scale cohort study recruiting the residents of the entire Fukushima prefecture. Study outcomes were primarily nonspecific psychological distress, depressive symptoms, post-traumatic stress symptoms, and anxiety symptoms. The rates of high-risk individuals determined by the studies varied significantly owing to methodological differences. Nevertheless, these rates were mostly high (nonspecific psychological distress, 8.3%-65.1%; depressive symptoms, 12%-52.0%; and post-traumatic stress symptoms, 10.5%-62.6%). Many studies focused on vulnerable populations such as children, mothers of young children, evacuees, and nuclear power plant workers. However, few studies reported on the intervention methods used or their effect on the survivors. As a conclusion, high rates of individuals with psychological conditions, as well as a wide range of mental conditions, were reported among the Fukushima nuclear disaster survivors in the first 8 years after the disaster. These findings demonstrate the substantial impact of this compound disaster, especially in the context of a nuclear catastrophe.

Evaluation of the Severity of Major Depression Using a Voice Index for Emotional Arousal.

Recently, the relationship between emotional arousal and depression has been studied. Focusing on this relationship, we first developed an arousal level voice index (ALVI) to measure arousal levels using the Interactive Emotional Dyadic Motion Capture database. Then, we calculated ALVI from the voices of depressed patients from two hospitals (Ginza Taimei Clinic (H1) and National Defense Medical College hospital (H2)) and compared them with the severity of depression as measured by the Hamilton Rating Scale for Depression (HAM-D). Depending on the HAM-D score, the datasets were classified into a no depression (HAM-D < 8) and a depression group (HAM-D ≥ 8) for each hospital. A comparison of the mean ALVI between the groups was performed using the Wilcoxon rank-sum test and a significant difference at the level of 10% (p = 0.094) at H1 and 1% (p = 0.0038) at H2 was determined. The area under the curve (AUC) of the receiver operating characteristic was 0.66 when categorizing between the two groups for H1, and the AUC for H2 was 0.70. The relationship between arousal level and depression severity was indirectly suggested via the ALVI.

Altered upright face recognition and presence of face inversion effect in temporal lobe epilepsy: An event-related potential study.

AIM: Facial recognition can be assessed by examining an event-related potential component, namely the N170. The amplitude of the N170 is larger in response to inverted faces than to upright faces. To examine facial processing in patients with temporal lobe epilepsy (TLE), we investigated the amplitude of the N170, the face inversion effect, and the association between social functioning and face-specific configuration processing. METHODS: Sixteen patients with TLE and 17 normal controls (NC) participated in this study. Event-related potentials in response to upright or inverted neutral faces and bicycles were recorded. Social functioning was assessed by the socioeconomic status of the participants using the 5-point Hollingshead-Redlich Scale. RESULTS: Compared with NC, patients with TLE had decreased N170 amplitudes. The inversion effect was observed for face stimuli in both groups; however, no inversion effect was observed for bicycle stimuli. Additionally, in TLE patients, but not in NC, socioeconomic status was significantly correlated with the N170 amplitudes in response to upright faces. CONCLUSION: In a social context, upright faces are processed as a whole. This process is impaired in TLE. Conversely, inverted faces are processed analytically. This function is normal in TLE. Abnormal face-specific configuration processing may contribute to lower social functioning in TLE.

General psychological distress among Japan Self-Defense Forces personnel dispatched on United Nations peacekeeping operations and their spouses.

AIM: The importance of family care during international deployment is emphasized within military organizations, but mental health interactions between deployed personnel and their spouses have not yet been assessed. This study addressed this gap by examining couples' mental health throughout a deployment period. METHODS: The mental health of 324 spousal dyads of Japan Self-Defense Forces personnel dispatched for a half-year United Nations Disengagement Observer Force mission was examined, using longitudinal data derived from a survey at four time points: one-month pre-deployment, initial deployment, middle deployment, and immediately after homecoming. The 30-item General Health Questionnaire was used to evaluate general psychological distress, with high scores (≥7) indicating adverse mental health. RESULTS: The spouses' general psychological distress was significantly higher compared with the deployed personnel (P < 0.001). The high general psychological distress of personnel was significantly related to that of their spouses (odds ratio = 2.24; 95% confidence interval, 1.32-3.80), and vice versa (odds ratio = 2.38; 95% confidence interval 1.39-4.08). CONCLUSION: Mental health care will be beneficial for not only deployed personnel but also their spouses.

Differential effects of voluntary wheel running and toy rotation on the mRNA expression of neurotrophic factors and FKBP5 in a post-traumatic stress disorder rat model with the shuttle-box task.

Life-threatening experiences can result in the development of post-traumatic stress disorder. We have developed an animal model for post-traumatic stress disorder (PTSD) using a shuttle box in rats. In this paradigm, the rats were exposed to inescapable foot-shock stress (IS) in a shuttle box, and then an avoidance/escape task was performed in the same box 2 weeks after IS. A previous study using this paradigm revealed that environmental enrichment (EE) ameliorated avoidance/numbing-like behaviors, but not hyperarousal-like behaviors, and EE also elevated hippocampal brain-derived neurotrophic factor (BDNF) expression. However, the differential effects of EE components, i.e., running wheel (RW) or toy rotation, on PTSD-like behaviors has remained unclear. In this experiment, we demonstrated that RW, toy rotation, and EE (containing RW and toy rotation) ameliorated avoidance/numbing-like behaviors, induced learning of avoidance responses, and improved depressive-like behaviors in traumatized rats. The RW increased the hippocampal mRNA expression of neurotrophic factors, especially BDNF and glial-cell derived neurotrophic factor. Toy rotation influenced FK506 binding protein 5 mRNA expression, which is believed to be a regulator of the hypothalamic-pituitary-adrenal (HPA)-axis system, in the hippocampus and amygdala. This is the first report to elucidate the differential mechanistic effects of RW and toy rotation. The former appears to exert its effects via neurotrophic factors, while the latter exerts its effects via the HPA axis. Further studies will lead to a better understanding of the influence of environmental factors on PTSD.

The relationship between dispositional empathy, psychological distress, and posttraumatic stress responses among Japanese uniformed disaster workers: a cross-sectional study.

BACKGROUND: Disaster workers suffer from psychological distress not only through the direct experience of traumatic situations but also through the indirect process of aiding disaster victims. This distress, called secondary traumatic stress, is linked to dispositional empathy, which is the tendency for individuals to imagine and experience the feelings and experiences of others. However, the association between secondary traumatic stress and dispositional empathy remains understudied. METHODS: To examine the relationship between dispositional empathy and mental health among disaster workers, we collected data from 227 Japan Ground Self-Defense Force personnel who engaged in international disaster relief activities in the Philippines following Typhoon Yolanda in 2013. The Impact of Event Scale-Revised and the Kessler Psychological Distress Scale were used to evaluate posttraumatic stress responses (PTSR) and general psychological distress (GPD), respectively. Dispositional empathy was evaluated through the Interpersonal Reactivity Index, which consists of four subscales: Perspective Taking, Fantasy, Empathic Concern, and Personal Distress. Hierarchial linear regression analyses were performed to identify the variables related to PTSR and GPD. RESULTS: High PTSR was significantly associated with high Fantasy (identification tendency, ß = 0.21, p < .01), high Personal Distress (the self-oriented emotional disposition of empathy, ß = 0.18, p < .05), and no experience of disaster relief activities (ß = 0.15, p < .05). High GPD was associated with high Personal Distress (ß = 0.28, p < .001), marital status (married, ß = 0.22, p < .01), being female (ß = 0.18, p < .01), medical unit (ß = 0.18, p < .05), and no experience of disaster relief activities (ß = 0.13, p < .05). CONCLUSIONS: Among Japanese uniformed disaster workers, high PTSR was associated with two subtypes of dispositional empathy: the self-oriented emotional disposition of empathy and high identification tendency, whereas high GPD was associated with high identification tendency. Educational interventions that aim to mitigate these tendencies might be able to relieve the psychological distress of disaster workers.

Detailed analysis of the Japanese version of the Rapid Dementia Screening Test using Arabic-hiragana conversion.

AIM: The number-transcoding task on the Japanese version of the Rapid Dementia Screening Test (RDST-J) requires conversion between Arabic and Chinese numerals (209 to , 4054 to , to 681, to 2027). In this task, questions and answers are written for Chinese-Arabic conversion. We reported that the RDST-J could distinguish subjects with Alzheimer's disease with a Clinical Dementia Rating Scale score of 0.5 from controls. In this study, we investigated the impact of changing the task to a hiragana-Arabic conversion. METHODS: Participants consisted of 45 patients with a Clinical Dementia Rating Scale score of 0.5 and 52 normal controls. RESULTS: The sensitivity and specificity of total scores ≥9 on the two RDST-J versions for discriminating subjects with a Clinical Dementia Rating Scale score of 0.5 from controls were 73.1% and 75.5%, respectively, on the original version, and 71.8% and 73.0%, respectively, on the revised version. CONCLUSIONS: The sensitivity and specificity of the revised version of the RDST-J was equivalent to those of the original version.

Unraveling complex relationships among dysphoric disorder, localization-related epilepsy, and mood disorders.

BACKGROUND: Dysphoric disorder (DD), characterized by intermittent pleomorphic symptoms, has been believed to be specific to epilepsy. However, our previous study revealed that DD in patients with localization-related epilepsy was associated with a lifetime diagnosis of mood disorders. The present study was conducted to estimate the prevalence of DD in patients with mood disorders, but not epilepsy, and to identify the clinical similarities and differences of DD in patients with either epilepsy or mood disorders. METHODS: Subjects consisted of 104 patients with localization-related epilepsy (group E) and 101 patients with DSM-IV mood disorders, but not with epilepsy (group M). After a diagnostic investigation for DD and the euthymic state, defined as the absence of any mood episodes during the last 12months, we compared the clinical characteristics of DD in patients from groups E and M. RESULTS: Dysphoric disorder was apparently more common in group M (56.4%) than in group E (21.2%). However, 86.0% of patients in group M showed a temporal overlap between DD and the noneuthymic state, while 68.2% of patients in group E did not show this overlap. Moreover, the noneuthymic state was significantly associated with symptoms of DD, indicating that the diagnosis of DD was more likely to be overestimated when the subjects were in a noneuthymic state. The prevalence of DD, temporally independent of the noneuthymic state (pure DD), was estimated at 13.4% and 7.0% in groups E and M, respectively, and pure DD was 1.91 times more common in patients with epilepsy than in those with mood disorders. Diagnosis of pure DD was significantly associated with increased suicidality in group E, but not group M. CONCLUSION: The present results suggest that DD is more familiar to epilepsy than mood disorders, although DD is not specific to epilepsy. Moreover, suicidality is specifically associated with DD in patients with epilepsy.

Detailed analysis of the Japanese version of the Rapid Dementia Screening Test, revised version.

AIM: The number-transcoding task on the Japanese version of the Rapid Dementia Screening Test (RDST-J) requires mutual conversion between Arabic and Chinese numerals (209 to , 4054 to , to 681, to 2027). In this task, question and answer styles of Chinese numerals are written horizontally. We investigated the impact of changing the task so that Chinese numerals are written vertically. METHODS: Subjects were 211 patients with very mild to severe Alzheimer's disease and 42 normal controls. Mini-Mental State Examination scores ranged from 26 to 12, and Clinical Dementia Rating scores ranged from 0.5 to 3. RESULTS: Scores of all four subtasks of the transcoding task significantly improved in the revised version compared with the original version. The sensitivity and specificity of total scores ≥9 on the RDST-J original and revised versions for discriminating between controls and subjects with Clinical Dementia Rating scores of 0.5 were 63.8% and 76.6% on the original and 60.1% and 85.8% on revised version. CONCLUSIONS: The revised RDST-J total score had low sensitivity and high specificity compared with the original RDST-J for discriminating subjects with Clinical Dementia Rating scores of 0.5 from controls.

Detailed analysis of error patterns in the number-transcoding task on the Japanese version of the Rapid Dementia Screening Test.

AIM: The number-transcoding task on the Japanese version of the Rapid Dementia Screening Test requires mutual conversion between Arabic and Chinese numerals (e.g. 209 → , 4054 → , → 681, → 2027). During this task, some characteristic errors have been seen among patients with Alzheimer's disease (AD). The objective of this study was to clarify whether the frequency of appearance of error patterns differs between patients with mild and severe AD according to Clinical Dementia Rating (CDR) scores. METHODS: A total of 250 patients with AD were recruited and subsequently categorized into two groups based on CDR scores (mild AD: CDR of 0.5 or 1; severe AD: CDR of 2 or 3). We analyzed 19 qualitative error patterns, including 15 that had been reported to date and 4 previously unreported errors, in each subtest. RESULTS: The frequency of appearance of two previously reported and four previously unreported errors in the mild and severe AD groups, respectively, were statistically significant. CONCLUSIONS: Characteristic error pattern distributions in number transcoding can be observed in patients with mild and severe AD according to CDR scores and offers useful information for interpreting cognitive screening data.

Detailed analysis of the supermarket task included on the Japanese version of the Rapid Dementia Screening Test.

AIM: The supermarket task, which is included in the Japanese version of the Rapid Dementia Screening Test, requires the quick (1 min) generation of words for things that can be bought in a supermarket. Cluster size and switches are investigated during this task. We investigated how the severity of dementia related to cluster size and switches on the supermarket task in patients with Alzheimer's disease. METHODS: We administered the Japanese version of the Rapid Dementia Screening Test to 250 patients with very mild to severe Alzheimer's disease and to 49 healthy volunteers. Patients had Mini-Mental State Examination scores from 12 to 26 and Clinical Dementia Rating scale scores from 0.5 to 3. Patients were divided into four groups based on their Clinical Dementia Rating score (0.5, 1, 2, 3). We performed statistical analyses between the four groups and control subjects based on cluster size and switch scores on the supermarket task. RESULTS: The score for cluster size and switches deteriorated according to the severity of dementia. Moreover, for subjects with a Clinical Dementia Rating score of 0.5, cluster size was impaired, but switches were intact. CONCLUSIONS: Our findings indicate that the scores for cluster size and switches on the supermarket task may be useful for detecting the severity of symptoms of dementia in patients with Alzheimer's disease.

Interictal dysphoric disorder in patients with localization-related epilepsy: Diagnostic relationships with DSM-IV psychiatric disorders and the impact of psychosocial burden.

BACKGROUND: Some patients with epilepsy develop intermittent and pleomorphic affective-somatoform symptoms, termed interictal dysphoric disorder (IDD). Other psychiatric disorders have been extensively investigated in patients with epilepsy, but there are few clinical studies investigating the comorbidity patterns of IDD and common psychiatric disorders (PDs). In particular, the impact of IDD on the psychosocial burden of patients remains unclear. METHODS: The participants were 128 adult Japanese outpatients with localization-related epilepsy (LRE). In order to determine the comorbidity patterns for IDD and PDs, we conducted a comprehensive diagnostic investigation for IDD and DSM-IV psychiatric disorders. Based on these analyses, participants were divided into groups according to the comorbidity patterns for IDD and PDs in order to compare both suicide risk and quality of life (QOL). RESULTS: The findings indicated that 19.5% of participants had IDD, and 55.5% had PDs. Younger age at epilepsy onset and refractory complex partial seizures were associated with IDD, but the duration and type of epilepsy were not. Patients with IDD were more likely to have comorbid PDs as follows: mood disorders (odds ratio, OR: 8.30; 95% confidence interval, CI: 3.15-21.83), anxiety disorders (OR: 8.81; 95% CI: 3.30-23.49), and psychotic disorders (OR: 7.72; 95% CI: 2.83-21.06). Group comparisons demonstrated that there were no patients with IDD but without PD. Furthermore, patients with IDD and with PDs had a significantly higher suicide risk and lower QOL compared to the other groups, even after adjusting for the influences of confounding factors. CONCLUSION: Interictal dysphoric disorder adds extreme psychosocial burden and is associated with multiple PDs in patients with LRE. The present study suggests that IDD has a specific prognostic significance. However, whether IDD is nosologically independent from conditions diagnosed using standardized psychiatric diagnostic systems such as DSM-IV must be further assessed by future research.

The effects of living environment on disaster workers: a one-year longitudinal study.

BACKGROUND: Defense Force workers engaged in disaster relief activities might suffer from strong psychological stress due to the tasks that they had been involved. We evaluated how living environments, work environments, and individual factors psychologically affect those who engaged in disaster relief activities. METHOD: Data generated with 1506 personnel engaged in the Great East Japan Earthquake relief activity were analyzed. Those who scored ≥25 points on the Impact of Events Scale-Revised and the Kessler Psychological Distress Scale (K10) were allocated into the high post-traumatic stress response (high-PTSR) group, and the high general psychological distress (high-GPD) group, respectively. RESULTS: The multiple logistic regression analysis extracted living environment (camping within the shelter sites) as the significant risk factor for both high-PTSR (OR = 3.39, 95 % CI 2.04-5.64, p < 0.001) and high-GPD (OR = 3.35, 95 % CI 1.77-6.34, p < 0.001) groups. CONCLUSION: It is desirable for disaster workers to have a living environment in which they can keep an appropriate distance from the victims.

The Japanese version of the Rapid Dementia Screening Test is effective compared to the clock-drawing test for detecting patients with mild Alzheimer's disease.

BACKGROUND: The Japanese version of the Rapid Dementia Screening Test (RDST-J) and the clock-drawing test (CDT) are both brief psychometric screening tools used to detect the severity of Alzheimer's disease. It remains unclear, however, which is more effective when screening for mild Alzheimer's disease. METHODS: We administered the RDST-J and CDT to 250 patients with very mild to severe Alzheimer's disease and to 49 healthy volunteers. Patients with a Mini-Mental State Examination score of 12-26 had Clinical Dementia Rating (CDR) scores from 0.5 to 3. Patients were divided into four groups according to CDR score. We performed one-way factorial anova between the four groups and control subjects based on the CDT and RDST-J scores. RESULTS: Data analysis revealed that RDST-J could distinguish patients with CDR 0.5 from the controls, but CDT could not. Furthermore, the sensitivity of a RDST-J score ≥8 was 57.1%, with a specificity of 81.0%, and the sensitivity of a RDST-J score ≥9 was 79.6%, with a specificity of 55.1% for discriminating CDR 0.5 from controls. CONCLUSIONS: RDST-J is a more effective tool than CDT for distinguishing CDR 0.5 from controls.

Severe Atelectasis due to Aspirated Valproic Acid Tablet.

A 60-year-old man treated with valproic acid (VPA) for epilepsy developed atelectasis and respiratory failure after an accidentally aspirated VPA tablet-induced mucus hypersecretion. Following bronchoscopic removal of the aspirated tablet, his respiratory status improved and massive sputum production did not recur. We hypothesized that the aspirated VPA tablet increased the expression of mucin-related genes, thereby increasing mucus production. Our in vitro experiments using a human respiratory epithelial cell line revealed that VPA directly upregulates the airway mucin-related genes. We believe that this is the first case report of aspirated VPA-induced severe atelectasis and respiratory failure, which were successfully treated with the bronchoscopic removal of the VPA tablet.

Molecular hydrogen supplementation in mice ameliorates lipopolysaccharide-induced loss of interest.

Aim: The objective of this study was to evaluate the potential of hydrogen in preventing and treating psychiatric symptoms, particularly depressed mood and loss of interest, and to explore its underlying mechanisms. A mouse model exhibiting inflammation-derived depressive symptoms was used for the investigation. Methods: Institute of Cancer Research mice were subjected to a 7-day intervention of either 30% hydrogen or 40 g per day of air via jelly intake. On the final day, lipopolysaccharide (LPS) was intraperitoneally administered at 5 mg/kg to induce inflammation-related depressive symptoms. Behavioral and biochemical assessments were conducted 24 h post-LPS administration. Results: Following LPS administration, a decrease in spontaneous behavior was observed; however, this effect was mitigated in the group treated with hydrogen. The social interaction test revealed a significant reduction in interactions with unfamiliar mice in the LPS-treated group, whereas the hydrogen-treated group exhibited no such decrease. No significant changes were noted in the forced-swim test for either group. Additionally, the administration of LPS in the hydrogen group did not result in a decrease in zonula occludens-1, a biochemical marker associated with barrier function at the cerebrovascular barrier and expressed in tight junctions. Conclusion: Hydrogen administration demonstrated a preventive effect against the LPS-induced loss of interest, suggesting a potential role in symptom prevention. However, it did not exhibit a suppressive effect on depressive symptoms in this particular model. These findings highlight the nuanced impact of hydrogen in the context of inflammation-induced psychiatric symptoms, indicating potential avenues for further exploration and research.

Augmentation of psychiatric symptom onset vulnerability in male mice due to mild traumatic brain injury.

Mild traumatic brain injury (mTBI) can induce psychiatric symptoms, including anxiety, depression, and diminished interest. These symptoms can manifest shortly after injury or exhibit delayed onset months or years later, often worsening in severity. Therefore, early intervention and effective treatment are crucial. However, mTBI lacks clear diagnostic markers, making the underlying pathophysiological mechanisms elusive. Additionally, there is a dearth of suitable animal models and a limited understanding of the biochemical changes in the brain that contribute to post-mTBI psychological symptoms. In this study, we hypothesized that mTBI can trigger brain vulnerability mechanisms, which eventually lead to symptom manifestation in response to subsequent stressors. Using a mouse model, we induced very mild blast-induced mTBI without overt trauma or behavioral changes and subsequently subjected the mice to psychological stress. We analyzed the behavioral alterations and gene expression changes in the brain, focusing on microglial and astrocytic markers involved in the immune system and immune responses. The mice exposed to both blast and defeat stress exhibited significantly lower preference scores in the social interaction test than the mice subjected to blast exposure alone, defeat stress alone, or the control condition. Gene expression analysis revealed a distinct set of genes associated with blast exposure during the development of psychiatric symptoms and genes associated with social defeat stress. The results revealed that neither blast exposure nor defeat stress alone significantly affected mouse social behavior; however, their combined influence resulted in noticeable aberrations in social interactions and/or interest. The findings of the present study provide critical insights into the complex interplay between mTBI and psychological stress. Additionally, they provide a novel mouse model for future research aimed at elucidating the pathophysiological mechanisms underlying the psychiatric symptoms associated with mTBI. Ultimately, this knowledge may enhance early intervention and therapeutic strategies for individuals with mTBI-related psychiatric disorders.