Depression

Effects and neural mechanisms of different physical activity on major depressive disorder based on cerebral multimodality monitoring: a narrative review

Major depressive disorder (MDD) is currently the most common psychiatric disorder in the world. It characterized by a high incidence of disease with the symptoms like depressed mood, slowed thinking, and reduced cognitive function. Without timely intervention, there is a 20-30% risk of conversion to treatment-resistant depression (TRD) and a high burden for the patient, family and society. Numerous studies have shown that physical activity (PA) is a non-pharmacological treatment that can significantly improve the mental status of patients with MDD and has positive effects on cognitive function, sleep status, and brain plasticity. However, the physiological and psychological effects of different types of PA on individuals vary, and the dosage profile of PA in improving symptoms in patients with MDD has not been elucidated. In most current studies of MDD, PA can be categorized as continuous endurance training (ECT), explosive interval training (EIT), resistance strength training (RST), and mind-body training (MBT), and the effects on patients' depressive symptoms, cognitive function, and sleep varied. Therefore, the present study was based on a narrative review and included a large number of existing studies to investigate the characteristics and differences in the effects of different PA interventions on MDD. The study also investigated the characteristics and differences of different PA interventions in MDD, and explained the neural mechanisms through the results of multimodal brain function monitoring, including the intracranial environment and brain structure. It aims to provide exercise prescription and theoretical reference for future research in neuroscience and clinical intervention in MDD.

Depression symptoms and suicide risk of internal medicine residents before and after first year of the COVID-19 pandemic

Introduction

Depression is a mental health disorder characterized by the presence of sadness or loss of the ability to feel pleasure, with a high incidence in patients with COVID 19. The investigations have focused on patient care and little on the care of health personnel, these being the ones with the highest mortality rate, so the objective of the study was to investigate the prevalence of depression symptoms and suicide risk and understand the association of depressive disorder and suicide risk with levels of serum cholesterol and low levels of serum cortisol among internal medicine fellows in a specialist medical hospital in Leon, Guanajuato, Mexico, before and after COVID-19.

Methods

In this longitudinal study, internal medicine residents were initially monitored for 2months before starting to care for patients with COVID-19. Participants were asked to fill out depression symptoms and suicide risk surveys. We measured the serum cholesterol and cortisol of each participant, and again after 11months of treating COVID-19 patients.

Results

Depression symptoms and suicide risk were assessed; significant differences were found between the two time periods for depression (p < 0.01), and no difference was found for suicide risk (p = 0.182). We found a significant correlation between serum cholesterol levels and suicide risk (r = 0.366, p < 0.01); we also found differences in serum cortisol levels (p < 0.01) and cholesterol (p < 0.0001) before and after the pandemic.

Conclusion

Caring for patients with COVID-19 in the hospital contributed to an increase in levels of depression symptoms and suicidal ideation, as well as differences in levels of cortisol and cholesterol in resident physicians of internal medicine; among the possible reasons for this change could be the conditions of personal protection while treating patients, the uncertainty in the first months of not knowing how the virus was transmitted and not having or knowing when vaccinations would be available, as well as the lack of a strategy of adequate mental health support from the institutions dedicated to their academic training.

BDNF Overexpression in the Ventral Hippocampus Promotes Antidepressant- and Anxiolytic-Like Activity in Serotonin Transporter Knockout Rats

BDNF plays a pivotal role in neuroplasticity events, vulnerability and resilience to stress-related disorders, being decreased in depressive patients and increased after antidepressant treatment. BDNF was found to be reduced in patients carrying the human polymorphism in the serotonin transporter promoter region (5-HTTLPR). The serotonin knockout rat (SERT^-/-) is one of the animal models used to investigate the underlying molecular mechanisms of depression in humans. They present decreased BDNF levels, and anxiety- and depression-like behavior. To investigate whether upregulating BDNF would ameliorate the phenotype of SERT^-/- rats, we overexpressed BDNF locally into the ventral hippocampus and submitted the animals to behavioral testing. The results showed that BDNF overexpression in the vHIP of SERT^-/- rats promoted higher sucrose preference and sucrose intake; on the first day of the sucrose consumption test it decreased immobility time in the forced swim test and increased the time spent in the center of a novel environment. Furthermore, BDNF overexpression altered social behavior in SERT^-/- rats, which presented increased passive contact with test partner and decreased solitary behavior. Finally, it promoted decrease in plasma corticosterone levels 60 min after restraint stress. In conclusion, modulation of BDNF IV levels in the vHIP of SERT^-/- rats led to a positive behavioral outcome placing BDNF upregulation in the vHIP as a potential target to new therapeutic approaches to improve depressive symptoms.

mGluR5 Facilitates Long-Term Synaptic Depression in a Stress-Induced Depressive Mouse Model

BACKGROUND

Glutamatergic system has been known to play a role in the pathogenesis of major depression disorder by inducing N-methyl-d-aspartate receptor-dependent long-term depression (LTD) or metabotropic glutamate receptors (mGluR)-dependent LTD. Here, we characterized the LTD in a chronic social defeat stress (CSDS)-induced depressive mouse model.

METHODS

CSDS was used to induce the depressive-like behaviors in C57BL/6 male mice, which were assessed using sucrose preference test and social interaction test. The synaptic strength including LTD and long-term potentiation (LTP) induced by paired-pulse low frequency stimulation (PP-LFS) was measured using whole-cell recording technique.

RESULTS

CSDS induced depressive-like behaviors and facilitated PP-LFS-induced LTD in hippocampal CA3-CA1 pathway in the susceptible mice. Interestingly, mGluR5 but not N-methyl-d-aspartate receptor mediated the PP-LFS-induced LTD. In addition, mGluR5 agonist dihydroxyphenylglycine promoted PP-LFS-induced LTD specifically in susceptible mice, which was diminished by activating the BDNF/TrkB signaling pathway.

CONCLUSIONS

Our results suggest that mGluR5-dependent LTD might be responsible for the development of depressive-like behaviors in CSDS-induced depression mice model.

Longitudinal Estimation of the Clinically Significant Change in the Treatment of Major Depression Disorder

Background: Although major depressive disorder is usually treated with antidepressants, only 50-70% of the patients respond to this treatment. This study applied Jacobson and Truax's (1991) methodology (reliable change index, RCI) to a sample of depressive patients being treated with one of two antidepressants to evaluate their functioning and the effect of certain variables such as severity and age. Method: Seventy-three depressive patients medicated with Escitalopram (n = 37) or Duloxetine (n = 36) were assessed using the Hamilton depression rating scale over a 24-week period. Results: They indicate that the RCI stabilizes in an absolute way starting in week 16, and it is not until week 24 that all of the patients become part of the functional population. We found limited statistical significance with respect to the RCI and the external variables. Conclusion: Our study suggests the need to accompany the traditional statistical methodology with some other clinical estimation systems capable of going beyond a simple subtraction between pre and posttreatment values. Hence, it is concluded that RCI estimations could be stronger and more stable than the classical statistical techniques.

An evolutionary approach to mania studying Sardinian immigrants to Argentina

Objective:

To ascertain lifetime prevalence of positivity to a screening questionnaire for bipolar disorders (BD) in Sardinian immigrants to Argentina and residents of Sardinia and assess whether such positivity affects quality of life (QoL) in either group. Our hypothesis is that screen positivity for BD may be more frequent in immigrants.

Methods:

Observational study. Subjects were randomly selected from the membership lists of associations of Sardinian immigrants in Argentina. A study carried out in Sardinia using the same methodology was used for comparison. The Mood Disorder Questionnaire was used to screen for mania/hypomania and the Short-Form Health Survey-12 to measure QoL.

Results:

A higher prevalence of manic/hypomanic episodes was found in Sardinian immigrants to Argentina (p < 0.0001; odds ratio = 3.0, 95% confidence interval 1.87-4.77). Positivity at screening was associated with a lower QoL both in Sardinian immigrants to Argentina and in residents of Sardinia.

Conclusions:

To the best of our knowledge, this is the first study to show a higher lifetime prevalence of manic/hypomanic episodes in a general-population sample of individuals who migrated to a foreign country. Our results are in agreement with the hypothesis that hyperactive/novelty-seeking features may represent an adaptive substrate in certain conditions of social change.