The gut-brain axis and cognitive control: A role for the vagus nerve

Survival requires the integration of external information and interoceptive cues to effectively guide advantageous behaviors, particularly foraging and other behaviors that promote energy acquisition and consumption. The vagus nerve acts as a critical relay between the abdominal viscera and the brain to convey metabolic signals. This review synthesizes recent findings from rodent models and humans revealing the impact of vagus nerve signaling from the gut on the control of higher-order neurocognitive domains, including anxiety, depression, reward motivation, and learning and memory. We propose a framework where meal consumption engages gastrointestinal tract-originating vagal afferent signaling that functions to alleviate anxiety and depressive-like states, while also promoting motivational and memory functions. These concurrent processes serve to favor the encoding of meal-relevant information into memory storage, thus facilitating future foraging behaviors. Modulation of these neurocognitive domains by vagal tone is also discussed in the context of pathological conditions, including the use of transcutaneous vagus nerve stimulation for the treatment of anxiety disorders, major depressive disorder, and dementia-associated memory impairments. Collectively, these findings highlight the contributions of gastrointestinal vagus nerve signaling to the regulation of neurocognitive processes that shape various adaptive behavioral responses.

The impact of self-referential processing on depression-linked negative interpretive bias

BACKGROUND AND OBJECTIVES

Cognitive theories propose that individuals with heightened depression are characterized by biases in memory and interpretation, favoring the processing of negative information. Individuals with heightened depression exhibit a negative memory bias, and this bias is disproportionately evident when emotional information is processed in a self-referential manner. In studies investigating whether individuals with heightened depression exhibit a negative interpretative bias, the measures employed have often been compromised by serious methodological limitations. When interpretation has been measured using an eye-blink modulation approach, which overcomes these limitations, evidence of depression-linked negative interpretive bias has emerged. However, the important issue of whether this bias depends upon self-referential processing has gone unresolved.

METHOD

In the present study, we assessed interpretation using the eye blink modulation approach, in participants scoring high or low on the Beck Depression Inventory-II. A simple manipulation ensured that ambiguous information either was, or was not, processed in a self-referential manner.

RESULTS

The results showed that, when ambiguous information was processed in a self-referential manner, participants scoring high on the BDI-II displayed blink magnitudes indicating greater negative interpretative bias compared to participants scoring low on the BDI-II. This was not the case when ambiguous information was processed in an other-referential manner.

LIMITATIONS

The present findings do not permit the inference that this negative interpretive bias causally contributes to depressive symptomatology.

CONCLUSIONS

The results support the hypothesis that people with high levels of depression display greater negative interpretive bias than people with low levels of depression, but only when ambiguous information is processed in a self-referential manner.

An investigation of the potential clinical utility of critical slowing down as an early warning sign for recurrence of depression

BACKGROUND AND OBJECTIVES

Much of the burden of depressive illness is due to relapses that occur after treatment into remission. Prediction of an individual's imminent depressive relapse could lead to just-in-time interventions to prevent relapse, reducing depression's substantial burden of disability, costs, and suicide risk. Increasingly strong relationships in the form of autocorrelations between depressive symptoms, a signal of a phenomenon described as critical slowing down (CSD), have been proposed as a means of predicting relapse.

METHODS

In the current study, four participants in remission from depression, one of whom relapsed, responded to daily smartphone surveys with depression symptoms. We used p-technique factor analysis to identify depression factors from over 100 survey responses. We then tested for the presence of CSD using time-varying vector autoregression and detrended fluctuation analysis.

RESULTS

We found evidence that CSD provided an early warning sign for depression in the participant who relapsed, but we also detected false positive indications of CSD in participants who did not relapse. Results from time-varying vector autoregression and detrended fluctuation analysis were not in agreement.

LIMITATIONS

Limitations include use of secondary data and a small number of participants with daily responding to a subset of depression symptoms.

CONCLUSIONS

CSD provides a compelling framework for predicting depressive relapse and future research should focus on improving detection of early warning signs reliably. Improving early detection methods for depression is clinically significant, as it would allow for the development of just-in-time interventions.

Current scenario and potential of music therapy in the management of diseases

Over the preceding years, music therapy has gained tremendous attention due to new findings of music in management of various conditions like Alzheimer's, depression, anxiety, insomnia, etc. Music is a non-invasive, patient-friendly and pleasant form of therapy with minimal or no side effects. It activates the reward pathway of brain by influencing several processes such as dopamine release, reduction in cortisol levels, increase in estrogen and testosterone levels. This review article focuses on advantages and disadvantages of music therapy, mechanism of action of music in brain and its effective applications in the management of different diseases. The article covers history of music therapy in America, Egypt, and India with practice of music therapy. The advanced effects of music therapy in autism, cancer, post-operative pain, Parkinson's disease, selective mutism, stroke, heart problems, pregnancy, eating disorders, bone fractures and obsessive compulsive disorders are discussed. Also the effect of music therapy on the quality of sleep and brain waves has been discussed. This is an established profession in western countries like America, UK, Australia, and Canada, but not in low-income countries like India where it needs to be standardized.

The antidepressant-like effect of doxycycline is associated with decreased nitric oxide metabolite levels in the prefrontal cortex

Doxycycline is an antibiotic that has shown neuroprotective, anti-inflammatory, and antidepressant-like effects. Low doses of doxycycline revert the behavioral and neuroinflammatory responses induced by lipopolysaccharide treatment in a mice model of depression. However, the molecular mechanisms involved in the antidepressant action of doxycycline are not yet understood. Doxycycline inhibits the synthesis of nitric oxide (NO), which increases after stress exposure. Inducible NO synthase (iNOS) inhibition also causes antidepressant-like effects in animal models sensitive to antidepressant-like effects such as the forced swimming test (FST). However, no direct study has yet investigated if the antidepressant-like effects of doxycycline could involve changes in NO-mediated neurotransmission. Therefore, this study aimed at investigating: i) the behavioral effects induced by doxycycline alone or in association with ineffective doses of a NO donor (sodium nitroprusside, SNP) or an iNOS inhibitor (1400 W) in mice subjected to the FST; and ii) doxycycline effects in NO metabolite levels in the prefrontal cortex and hippocampus these animals. Male mice (8 weeks) received i.p. injection of saline or doxycycline (10, 30, and 50 mg/kg), alone or combined with SNP (0.1, 0.5, and 1 mg/kg) or 1400 W (1, 3, and 10 µg/kg), and 30 min later were submitted to the FST. Animals were sacrificed immediately after, and NO metabolites nitrate/nitrite (NOx) were measured in the prefrontal cortex and hippocampus. Doxycycline (50 mg/kg) reduced both the immobility time in the FST and NOx levels in the prefrontal cortex of mice compared to the saline group. The antidepressant-like effect of doxycycline in the FST was prevented by SNP (1 mg/kg) pretreatment. Additionally, sub-effective doses of doxycycline (30 mg/kg) associated with 1400 W (1 µg/kg) induced an antidepressant-like effect in the FST. Altogether, our data suggest that the reducing NO levels in the prefrontal cortex through inhibition of iNOS could be related to acute doxycycline treatment resulting in rapid antidepressant-like effects in mice.

HIF-1A regulates cognitive deficits of post-stroke depressive rats

Post-stroke depression (PSD) is a serious neuropsychiatric complication post stroke and leads to cognitive deficits. This study was conducted to explore the molecular mechanism of hypoxia-inducible factor-1α (HIF-1A) in cognitive dysfunction in rats with PSD. The rat model of PSD was established by middle cerebral artery occlusion, followed by 3 weeks of treatment with chronic unpredictable mild stress. The levels of miR-582-5p, HIF-1A, and neighbor of Brca1 gene (NBR1) in brain tissues were determined using RT-qPCR. The behaviors and cognitive capacity of rats were evaluated by various behavioral tests. PSD rats were injected with HIF-1A/miR-582-5p lowexpression vectors or NBR1 overexpression vectors via stereotactic method. The binding of HIF-1A to NBR1 or miR-582-5p was analyzed by chromatin immunoprecipitation and dual-luciferase assay. HIF-1A and NBR1 were highly expressed while miR-582-5p was poorly expressed in the brain of PSD rats. HIF-1A inhibition alleviated cognitive dysfunction of PSD rats. miR-582-5p was the upstream miRNA of HIF-1A, and HIF-1A specifically interacted with the NBR1 promoter to enhance NBR1 expression. miR-582-5p downregulation and NBR1 upregulation reversed the alleviative role of HIF-1A inhibition in cognitive dysfunction of PSD rats. In summary, HIF-1A inhibition may be a therapeutic target for cognitive dysfunction post PSD.

N-acetylcysteine ameliorates chemotherapy-induced impaired anxiety and depression-like behaviors by regulating inflammation, oxidative and cholinergic status, and BDNF release

Mood disorders caused by chemotherapy have become more important as the survival of cancer patients increases, and new studies in this field will contribute to the prevention of this disorder. For this purpose, we used methotrexate, a chemotherapeutic agent frequently preferred in oncological cases. Mtx was administered as a single dose of 100 mg/kg intraperitoneally to male Wistar albino rats. Since oxidative stress plays an important role in chemotherapy-induced emotional impairment, n-acetylcysteine (NAC), a potent antioxidant, was administered at 500 mg/kg in two doses before Mtx administration. We evaluated anxiety and depression-like behaviors 24 h after Mtx administration, as well as some oxidative and inflammatory markers in blood serum and hippocampal tissue, acetylcholinesterase activity (AChE), and brain-derived neurotrophic factor (BDNF) release in hippocampal tissue. In rats, Mtx induced anxiety and depression-like behaviors as well as abnormalities in oxidative and inflammatory markers in blood serum and hippocampal tissue, increased AChE activity in hippocampal tissue, and decreased BDNF release. NAC treatment was found to ameliorate Mtx-induced anxiety and depression-like behaviors, increase antioxidant capacity, reduce oxidative stress and inflammatory response, and regulate AChE activity and BDNF release. In conclusion, the fact that NAC treatment of Mtx was effective is important for revising the treatment strategies for individuals suffering from this disorder, and this effect is thought to be related to the antioxidant and anti-inflammatory power of NAC.

Pre-pandemic adversity and maternal mental health during the COVID-19 pandemic: the mediating role of pandemic stress and family relationships

BACKGROUND

The COVID-19 pandemic was a time of increased stress for families. Parents with a history of adversity may have been at higher risk of experiencing mental health problems during this time. The current study aims to investigate the relationship between pre-pandemic adversity pandemic related stressors and maternal mental health outcomes during the pandemic.

METHODS

Data was drawn from the Mothers' and Young People's Study (MYPS), a longitudinal of first time mothers and their children. Participants were 418 mothers who completed the MYPS COVID-19 sub-study. Data was collected during pregnancy, at 1, 4, 10 years postpartum, and during the COVID-19 pandemic (approximately 14 years postpartum). Path-analysis was used to test the relationship indirect relationship between pre-pandemic adversity and maternal depressive and anxiety symptoms, via family functioning and pandemic related stress.

RESULTS

The hypothesised model was a good fit to the data accounting for 34 % and 33 % of the variance in maternal depressive and anxiety scores, respectively. A significant indirect effect was found between pre-pandemic adversity and both maternal anxiety and depressive systems via family relationships during the pandemic and pandemic related stress.

LIMITATIONS

MYPS participants who took part in the COVID-19 sub-study were more likely to be older, have a higher level of education, and speak English as a first language, compared to the total MYPS sample.

CONCLUSIONS

Family inclusive service responses which aim to strengthen family relationships may be particularly important for families where there is a history of adversity to support parental mental health.

Beliefs about depression relate to active and avoidant coping in high-symptom adolescents

BACKGROUND

Perceptions of personal attributes as less malleable are associated with more severe depression symptoms and less active coping in youth. Perceptions of depression itself as relatively fixed have been linked to more severe depression symptoms; however, it is not known how beliefs about depression relate to active and avoidant coping behaviors in particular.

METHODS

We gathered information about beliefs about depression and activation and avoidance behaviors among 104 adolescents with high depression symptoms. The primary depression belief examined was prognostic pessimism, or the belief that depression is relatively permanent. We calculated correlations between this belief and activation and avoidance/rumination behaviors.

RESULTS

Prognostic pessimism was negatively correlated with behavioral activation scores (r = -0.31; p = .001), and was positively correlated with behavioral avoidance/rumination scores (r = 0.30; p = .002).

LIMITATIONS

This data was cross-sectional, and relied on self-report measures of depression beliefs and behaviors.

CONCLUSIONS

Adolescents who believe that depression is relatively permanent might feel less motivated to engage in effortful activation behaviors, instead favoring avoidance. These results may help elucidate the ways in which malleability beliefs relate to mental health outcomes among adolescents, and highlight prognostic pessimism as a potential treatment target for reducing depressogenic behaviors.

Facilitators of, barriers to, and preferences for e-mental health interventions for depression and anxiety in men: Metasynthesis and recommendations

BACKGROUND

Little is known about men's use of online mental health (eMH) interventions and factors that promote their engagement or attrition. We aimed to synthesise the qualitative literature on men's preferences for, attitudes towards, and experiences of using eMH interventions for depression and anxiety, and develop recommendations from the findings.

METHOD

Systematic searches were conducted (Jan 2000-Oct 2020) in six databases; study quality was assessed using Qualsyst with a minimum total of 0.55 required for inclusion. Extracted data were synthesised using meta-aggregation.

RESULTS

Eight studies met inclusion criteria and three synthesised findings were generated. (1) Facilitators of men's eMH use: finding apps and technology motivating and convenient, support and encouragement from important others, and interventions allowing men to take action, gain control over their mental health, and resulting in positive outcomes; (2) Barriers to men's eMH use: lack of free time, predicted or experienced lack of benefit from use, and technical difficulties; (3) What men want in eMH: personalised, tailored, relevant interventions that are bright and easy to use, with information presented in multiple formats, psychoeducation, exercises, self-monitoring, information on further resources, and the option of clinician involvement, without any repetitive questioning, boring tools, or negative feedback.

LIMITATIONS

All included studies were conducted in high income, 'Western' countries; most data related to experiences of using an existing eMH intervention within a trial, rather than in 'real world' settings where eMH acceptability is generally lower and experiences may differ.

CONCLUSIONS

Practice, research, and policy recommendations are presented.

Prevalence and factors associated with depression and anxiety among older adults: A large-scale cross-sectional study in China

BACKGROUND

To determine the prevalence of depression and anxiety among older adults in China, and explore the associated factors.

METHODS

This cross-sectional study recruited participants between October 2022 and December 2022. The sample collection utilized a multi-stage stratified equal probability random sampling method. This study included 8436 older adults who underwent interviews utilizing standardized assessment instruments. The assessment of depressive symptoms employed the Patient Health Questionnaire 9, while the evaluation of anxiety utilized the Generalized Anxiety Disorder 7. Multivariate logistic regression was conducted to determine the odds ratio and 95 % confidence interval (CI).

RESULTS

The weighted prevalence rates for depression and anxiety were 2.79 % (95 % CI: 2.38 %-3.28 %) and 1.39 % (95 % CI: 1.12 %-1.74 %), respectively. Older adults who were female, widowed, had irregular dietary habits, spent <1 h per day using electronic devices for socializing and entertainment, engaged in >8 h of sedentary behavior per day, and had chronic diseases (cardiovascular disease, cerebrovascular disease, insomnia, and Chronic gastroenteritis) displayed a higher likelihood of encountering symptoms indicative of depression and anxiety. Conversely, older adults living in rural areas and those who walked daily were less prone to experience symptoms of depression and anxiety.

CONCLUSIONS

This study suggests that the psychological well-being of older adults should be cared for when treating chronic diseases. Moreover, families, communities, and clinics should recognize that supporting regular diets, providing social engagement and recreational activities, encouraging physical activity, and minimizing sedentary behavior can reduce the risk of depression and anxiety.

The role of perinatal maternal symptoms of depression, anxiety and pregnancy-specific anxiety for infant's self-regulation: A prospective longitudinal study

BACKGROUND

Maternal symptoms of anxiety and depression are highly prevalent during pregnancy and postpartum and have the potential to impact fetal development and offspring behavior. However, research on the effects of fetal exposure to maternal subclinical affective symptoms on infant self-regulation is still lacking. Self-regulation provides a fundamental precondition for healthy development and overall life success whereas dysfunctional self-regulation can lead to behavioral problems, poor academic achievement, social rejection, and physical/mental disorders. During pregnancy and infancy, children largely depend upon their mothers in order to successfully regulate their internal states. Given the high prevalence of mothers suffering from anxiety and depressive symptoms during pregnancy and after childbirth, the aim of the present study is to explore how maternal affective symptoms change during the pre- and postnatal period, and how measures obtained in pregnancy and beyond impact self-regulation in infants, as indicated by crying-, sleeping-, and/or feeding problems.

METHODS

This prospective longitudinal study investigates the effects of maternal symptoms of depression, anxiety, and pregnancy-specific anxiety on infant's self-regulation in N = 225 mother-infant dyads. Maternal affective symptoms were examined at five prenatal and three postnatal time-points using the Edinburgh Postnatal Depression Scale (EPDS), the State-Trait Anxiety Inventory (STAI) and the Pregnancy Related Anxiety Questionnaire Revised (PRAQ-R2). Infant's self-regulation was assessed twice - at the age of three and six months - using the Crying Feeding Sleeping Scale (SFS).

RESULTS

Maternal pregnancy-specific anxiety was the most significant predictor for infant self-regulatory problems. It predicted crying-, sleeping, and feeding problems and explained up to 18 % of the variance. Even when controlling for maternal postpartum affective symptoms, pregnancy-specific anxiety remained a significant predictor for infant self-regulation problems.

LIMITATIONS

Rather homogenous sample (high socioeconomic status). Data based on maternal reports of infant behavior.

CONCLUSIONS

Our results suggest that fetal exposure to maternal affective symptoms - specifically pregnancy-related anxiety - plays a substantial role in the development of infant self-regulation problems, potentially mediated by epigenetic modifications. Importantly, even though maternal symptoms of depression and anxiety only reached subclinical levels, they were predictive for infant crying-, sleeping-, and feeding problems. Our findings underline the importance of early prevention and clearly tailored interventions during pregnancy and postpartum to prevent adverse outcome for mother, child and family.

The impact of sleep disturbances on suicide risk among people living HIV: An eleven-year national cohort

OBJECTIVES

The suicide rate among individuals who experience sleep disturbances is five times higher than in the general population. Up to 70 % of people living with HIV (PLHIV) experience sleep disturbances. This study's purpose was to determine whether this population has higher rates of suicide compared to those without sleep disorders. Possible risk factors were also explored.

METHODS

A secondary analysis of nationwide data on all males and females over 15 years old with HIV living in Taiwan was conducted from January 1, 2005, to December 31, 2016. Sleep disturbances were identified through recorded diagnoses and medical treatments. Cox proportional hazard models and hazard ratios (HRs) and mediation analysis were employed to estimate the association between sleep disturbances and suicide risk during the follow-up period.

RESULTS

Of the 5680 PLHIV, 72 suicide events were reported. The suicide incidence rate among PLHIV suffering from sleep disturbances was 769 per 100,000 person-years. Sleep disturbances were associated with a significantly increased risk of suicide (AHR = 1.75, 95 % CI 1.02-3.02, p = 0.0429). A premium-based monthly salary of <24,000 (NT $) was also associated with an increased hazard of suicide (AHR = 4.14, 95 % CI 1.60-10.75, p = 0.0035). The pathway effect analysis using potential outcomes showed that depression did not mediate the effect of sleep disturbance on suicide.

CONCLUSIONS

Sleep disturbances were associated with higher suicide rates, even after adjusting for pre-existing depression. These findings suggest that paying attention to suicidal ideation among PLHIV suffering from sleep disturbances is necessary.

Overview of Depression

Depressive disorders encompass a spectrum of diagnoses and are more common in women and transgender individuals. Diagnosis involves thorough history-taking and exclusion of underlying medical disorders. The emergency physician should assess the risk of self-harm and consider environmental and social factors prior to disposition.

Psychological impact of first admission with cardiovascular disease in a tertiary hospital in Oman

Background and objectives

Cardiovascular diseases (CVD) are associated with substantial psychological effects that can adversely influence long term prognosis. The aim of this study was to determine the psychological effect of the first hospital admission for acute coronary syndrome (ACS) or congestive heart failure (CHF) in an adult Omani population.

Methods

This cross-sectional questionnaire based study used the Hospital Anxiety and Depression Scale. Patients were recruited from the in-patient cardiology and medical wards of our institution. Patients with a prior hospital admission for CHF and ACS were excluded. The questionnaire was administered between days 3 and 7 after admission once patients were clinically stable.

Results

The study included 116 patients (mean age 60.3 + 13.8 years; 78 (67.8%) men), comprising 52 patients with ACS and 64 patients with CHF. Based on the scores, a total of 45 (38.8%) patients had moderate to severe anxiety, and 32 (27.6%) had moderate to severe depression. Patients with severe anxiety tended to be younger, and no other factors predicted anxiety or depression. The proportion of patients with severe depression was higher among patients with CHF (31.4%), and no other differences were observed between patients with ACS or CHF.

Conclusion

A substantial proportion of patients admitted to our institution in Oman with CVD had severe anxiety and depression. Treating physicians and caregivers should be more open to identifying these patients, and steps should be taken to address their psychological wellbeing along with the medical management of their illness.

An FRET-based and ER-targeting fluorescent probe for tracking superoxide anion (O2•-) in the hippocampus of the depressive mouse

Exploration of the pathway for the excessive generation of O2•- in hippocampus during depression is critical for the study on molecular mechanism of depression, and is currently still inconclusive. Herein, we put forward a hypothesis that depression increases the generation of O2•- in hippocampus by triggering ER stress, and verified this hypothesis by constructing an FRET-based ER-targeting fluorescent probe (ER-CRh) which can provide ratiometric detection of O2•- with high sensitivity and selectivity. The probe ER-CRh showed desirable ER-targeting capability, and could detect the endogenous O2•- in the ER of the hippocampal neuronal cells experiencing ER stress. Fluorescence imaging indicates that ER-CRh possesses the capability to penetrate the blood-brain barrier in mouse, and depression could promote the production of endogenous O2•- in hippocampus. Western blotting analysis reveals that the proteins GRP78 and CHOP from the hippocampus of depressive mouse show an up-regulated expression, and it suggests depression causes ER stress in hippocampal neurons. These findings prove our hypothesis, and could conduce to develop safe and effective antidepressants by the protection and repair of hippocampal neurons.