Dopamine System Dysregulation in Major Depressive Disorders

Specific Foods Associated with Depressive Symptoms among Young Adults and Their Bioactive Effects

Depression represents a widespread and devastating psychiatric public health challenge globally. It is particularly prevalent among young adults in Korea. Certain foods may have medicinal properties that alleviate depressive symptoms. This study aimed to examine the association between specific foods and depressive symptoms among young adults, exploring their bioactive effects and possible mechanisms. We conducted a cross-sectional study involving 1000 Korean young adults aged 18-39 years. Food frequency questionnaires were used to assess diets and their associations with depressive symptoms. Results from multivariable logistic regression analysis indicated associations between several specific foods and their effects: milk (odds ratio = 0.58, 95% confidence interval: 0.36-0.94), eggs (0.55, 0.35-0.87), bananas (0.58, 0.36-0.94), oranges (0.62, 0.40-0.96), sweet potatoes (0.60, 0.37-0.97), mushrooms (0.53, 0.31-0.92, females only), and kimchi (0.40, 0.17-0.95, males only). Furthermore, molecular docking indicated that hesperidin had the highest docking score of 5.86 in oranges. Several bioactive compounds identified as potentially beneficial in combatting depression include calcium, casein, alpha-lactalbumin, tryptophan (TRP), vitamin B6 and B12, magnesium, flavonoids (especially hesperidin), carotenoids, ergothioneine, fiber, and probiotics. To recommend these foods in the management of depression among young adults, further clinical intervention studies are necessary.

Investigating the association between metabolic syndrome conditions and perinatal mental illness: a national administrative claims study

BACKGROUND

Although the association between mental disorder and metabolic syndrome as a bidirectional relationship has been demonstrated, there is little knowledge of the cumulative and individual effect of these conditions on peripartum mental health. This study aims to investigate the association between metabolic syndrome conditions (MetS-C) and maternal mental illness in the perinatal period, while exploring time to incident mental disorder diagnosis in postpartum women.

METHODS

This observational study identified perinatal women continuously enrolled 1 year prior to and 1 year post-delivery using Optum's de-identified Clinformatics® Data Mart Database (CDM) from 2014 to 2019 with MetS-C i.e. obesity, diabetes, high blood pressure, high triglycerides, or low HDL (1-year prior to delivery); perinatal comorbidities (9-months prior to and 4-month postpartum); and mental disorder (1-year prior to and 1-year post-delivery). Additionally, demographics and the number of days until mental disorder diagnosis were evaluated in this cohort. The analysis included descriptive statistics and multivariable logistic regression. MetS-C, perinatal comorbidities, and mental disorder were assessed using the International Classification of Diseases, Ninth, and Tenth Revision diagnosis codes.

RESULTS

372,895 deliveries met inclusion/exclusion criteria. The prevalence of MetS-C was 13.43%. Multivariable logistic regression revealed prenatal prevalence (1.64, CI = 1.59-1.70) and postpartum incident (1.30, CI = 1.25-1.34) diagnosis of mental health disorder were significantly higher in those with at least one MetS-C. Further, the adjusted odds of having postpartum incident mental illness were 1.51 times higher (CI = 1.39-1.66) in those with 2 MetS-C and 2.12 times higher (CI = 1.21-4.01) in those with 3 or more MetS-C. Young women (under the age of 18 years) were more likely to have an incident mental health diagnosis as opposed to other age groups. Lastly, time from hospital discharge to incident mental disorder diagnosis revealed an average of 157 days (SD = 103 days).

CONCLUSION

The risk of mental disorder (both prenatal and incident) has a significant association with MetS-C. An incremental relationship between incident mental illness diagnosis and the number of MetS-C, a significant association with younger mothers along with a relatively long period of diagnosis mental illness highlights the need for more screening and treatment during pregnancy and postpartum.

Inhibition of 14-3-3 proteins increases the intrinsic excitability of mouse hippocampal CA1 pyramidal neurons

14-3-3 proteins are a family of regulatory proteins that are abundantly expressed in the brain and enriched at the synapse. Dysfunctions of these proteins have been linked to neurodevelopmental and neuropsychiatric disorders. Our group has previously shown that functional inhibition of these proteins by a peptide inhibitor, difopein, in the mouse brain causes behavioural alterations and synaptic plasticity impairment in the hippocampus. Recently, we found an increased cFOS expression in difopein-expressing dorsal CA1 pyramidal neurons, indicating enhanced neuronal activity by 14-3-3 inhibition in these cells. In this study, we used slice electrophysiology to determine the effects of 14-3-3 inhibition on the intrinsic excitability of CA1 pyramidal neurons from a transgenic 14-3-3 functional knockout (FKO) mouse line. Our data demonstrate an increase in intrinsic excitability associated with 14-3-3 inhibition, as well as reveal action potential firing pattern shifts after novelty-induced hyperlocomotion in the 14-3-3 FKO mice. These results provide novel information on the role 14-3-3 proteins play in regulating intrinsic and activity-dependent neuronal excitability in the hippocampus.

Neurobiological and psychological factors to depression

Major Depressive Disorder (MDD) is a common condition with complex psychological and biological background. While its aetiology is still unclear, chronic stress stands amongst major risk factors to MDD pathogenesis. When researching on MDD, it is necessary to be familiar with the neurobiological effects of several prominent contributors to the chronic stress factor experienced across hypothalamic-pituitary-adrenal (HPA) axis, neurotransmission, immune system reflexivity, and genetic alterations. Bi-directional flow of MDD pathogenesis suggests that psychological factors produce biological effects. Here, a summary of how the MDD expresses its mechanisms of action across an overactive HPA axis, the negative impacts of reduced neurotransmitter functions, the inflammatory responses and their gene x environment interactions. This paper builds on these conceptual factors and their input towards the MDD symptomatology with a purpose of synthesising the current findings and create an integrated view of the MDD pathogenesis. Finally, relevant treatment implications will be summarised, along with recommendations to a multimodal clinical practice.

Influence of epinephrine reactivity to stress on meat quality in goats

The magnitude of physiological responses to a stressor can vary among individual goats within a herd; however, whether these differences can differentially affect meat quality is not known. This study was conducted to determine the influence of the magnitude of epinephrine response (ER) to acute stress on muscle metabolome and meat quality in goats. Male Spanish goats (6 mo old) were transported for 180 min. (N = 75 goats; 25 goats/d) to impose stress. Blood samples were obtained after transport for analysis of physiological responses. Goats were slaughtered using humane procedures and samples were collected for muscle metabolomics and meat quality analyses. The data obtained from blood and muscle/meat analysis were then categorized based on epinephrine concentrations into low (LE), medium (ME), and high (HE) ER groups (n = 12/ER group). The physiological and meat quality variables were analyzed as a Completely Randomized Design in SAS, and metabolomics data were analyzed using R software. Plasma glucose concentrations were significantly high in the HE group, low in the LE group, and intermediate in the ME group (P < 0.05). However, leukocyte counts and cortisol, norepinephrine, blood urea nitrogen, and creatine concentrations were not different among the ER groups. Muscle (Longissimus dorsi) glycogen concentrations (15 min postmortem) were significantly higher (P < 0.05) in the ME and LE groups than in the HE group. However, postmortem Longissimus muscle pH and temperature (15 min and 24 h), 24 h calpastatin and desmin levels, and rib chop color (L*, a*, and b*), cooking loss, and Warner-Bratzler shear force values were unaffected by ER. Targeted metabolomics analysis of Longissimus muscle (15 min) revealed that diacyl phosphatidylcholines (C38:0; 40:6) and sphingomyelin (C20:2) were significantly different (P < 0.05) among the ER groups, with the concentrations of these metabolites being consistently high in the LE group. These differential muscle metabolite concentrations suggest that ER can influence biochemical pathways associated with cell membrane integrity and signaling. ER had a significant effect on dopamine concentrations, with the levels increasing with increasing levels of ER. The results indicate that differences in epinephrine reactivity can influence selected physiological responses and muscle metabolites; however, it does not significantly influence meat quality attributes.

Predictive modeling of response to repetitive transcranial magnetic stimulation in treatment-resistant depression

Identifying predictors of treatment response to repetitive transcranial magnetic stimulation (rTMS) remain elusive in treatment-resistant depression (TRD). Leveraging electronic medical records (EMR), this retrospective cohort study applied supervised machine learning (ML) to sociodemographic, clinical, and treatment-related data to predict depressive symptom response (>50% reduction on PHQ-9) and remission (PHQ-9 < 5) following rTMS in 232 patients with TRD (mean age: 54.5, 63.4% women) treated at the University of California, San Diego Interventional Psychiatry Program between 2017 and 2023. ML models were internally validated using nested cross-validation and Shapley values were calculated to quantify contributions of each feature to response prediction. The best-fit models proved reasonably accurate at discriminating treatment responders (Area under the curve (AUC): 0.689 [0.638, 0.740], p < 0.01) and remitters (AUC 0.745 [0.692, 0.797], p < 0.01), though only the response model was well-calibrated. Both models were associated with significant net benefits, indicating their potential utility for clinical decision-making. Shapley values revealed that patients with comorbid anxiety, obesity, concurrent psychiatric medication use, and more chronic TRD were less likely to respond or remit following rTMS. Patients with trauma and former tobacco users were more likely to respond. Furthermore, delivery of intermittent theta burst stimulation and more rTMS sessions were associated with superior outcomes. These findings highlight the potential of ML-guided techniques to guide clinical decision-making for rTMS treatment in patients with TRD to optimize therapeutic outcomes.

Dopamine Pharmacodynamics: New Insights

Dopamine is a key neurotransmitter involved in physiological processes such as motor control, motivation, reward, cognitive function, and maternal and reproductive behaviors. Therefore, dysfunctions of the dopaminergic system are related to a plethora of human diseases. Dopamine, via different circuitries implicated in compulsive behavior, reward, and habit formation, also represents a key player in substance use disorder and the formation and perpetuation of mechanisms leading to addiction. Here, we propose dopamine as a model not only of neurotransmission but also of neuromodulation capable of modifying neuronal architecture. Abuse of substances like methamphetamine, cocaine, and alcohol and their consumption over time can induce changes in neuronal activities. These modifications lead to synaptic plasticity and finally to morphological and functional changes, starting from maladaptive neuro-modulation and ending in neurodegeneration.

Neuromodulatory Effects Induced by the Association of Moringa oleifera Lam., Tribulus terrestris L., Rhodiola rosea Lam., and Undaria pinnatidifida Extracts in the Hypothalamus

The present study investigated the role of a commercial formulation constituted by herbal extracts from Rhodiola rosea, Undaria pinnatifida, Tribulus terrestris, and Moringa oleifera. The formulation was analysed for determining the content in total phenols and flavonoids and scavenging/reducing properties. The formulation was also tested on isolated mouse hypothalamus in order to investigate effects on serotonin, dopamine, neuropeptide Y (NPY), and orexin A. The gene expression of gonadrotopin releasing hormone (GnRH) was also assayed. The formulation was able to reduce dopamine and serotonin turnover, and this could be related, albeit partially, to the capability of different phytochemicals, among which hyperoside and catechin to inhibit monoaminooxidases activity. In parallel, the formulation was effective in reducing the gene expression of NPY and orexin-A and to improve the gene expression of GnRH. In this context, the increased GnRH gene expression induced by the formulation may contribute not only to improve the resistance towards the stress related to ageing, but also to prevent the reduction of libido that could be related with a stimulation of the serotoninergic pathway. According to the in silico analysis, hyperoside could play a pivotal role in modulating the gene expression of GnRH. Regarding NPY and orexin A gene expression, no direct interactions between the formulation phytochemicals and these neuropeptides were anticipated; thus, suggesting that the pattern of gene expression observed following exposure of the hypothalamus to the formulation may be secondary to inhibitory effects of dopamine and serotonin turnover. Concluding, the present study demonstrated the efficacy of the formulation in exerting neuromodulatory effects at the hypothalamic level; thus, suggesting the potential to contrast stress and fatigue.

Alzheimer Disease-Link With Major Depressive Disorder and Efficacy of Antidepressants in Modifying its Trajectory

Alzheimer disease (AD) is a devastating neurodegenerative disorder that affects millions of individuals worldwide, with no effective cure. The main symptoms include learning and memory loss, and the inability to carry out the simplest tasks, significantly affecting patients' quality of life. Over the past few years, tremendous progress has been made in research demonstrating a link between AD and major depressive disorder (MDD). Evidence suggests that MDD is commonly associated with AD and that it can serve as a precipitating factor for this disease. Antidepressants such as selective serotonin reuptake inhibitors, which are the first line of treatment for MDD, have shown great promise in the treatment of depression in AD, although their effectiveness remains controversial. The goal of this review is to summarize current knowledge regarding the association between AD, MDD, and antidepressant treatment. It first provides an overview of the interaction between AD and MDD at the level of genes, brain regions, neurotransmitter systems, and neuroinflammatory markers. The review then presents current evidence regarding the effectiveness of various antidepressants for AD-related pathophysiology and then finally discusses current limitations, challenges, and future directions.

Curcumin as a Multifunctional Spice Ingredient against Mental Disorders in Humans: Current Clinical Studies and Bioavailability Concerns

BACKGROUND

Mental disorders in terms of depression, anxiety, and stress are one of the major causes of burden globally. Over the last two decades, the use of plant-based substances in the treatment of mental disorders in combination or not with medication has increasingly attracted the interest of the scientific research community. However, even if there is a plethora of naturally occurring bioactive compounds, most of them have low bioavailability, rendering them unable to insert into the bloodstream to exert their biological activities.

METHODS

This is a comprehensive narrative review that critically summarizes and scrutinizes the new approaches to the treatment of mental disorders using curcumin, also highlighting its bioavailability properties. The most accurate were searched using effective and relevant keywords.

RESULTS

This narrative review reveals substantial evidence that curcumin can exert significant effects on several mental disorders. However, despite the low cost, the extensive and confirmed potency of curcumin and its involvement in signaling pathways and the scientifically confirmed data regarding its molecular mechanisms of action against mental disorders, this naturally occurring compound presents low oral bioavailability. Pharmaceutical technology has provided solutions to increase the bioavailability of curcumin. Combination with piperine, galactomannosides, liposomal formulation or nanoformulation overcomes the bioavailability and solubility disadvantages.

CONCLUSIONS

Although curcumin demonstrates anti-anxiety, anti-depressive and anti-stress properties, studies on humans are limited and heterogeneous. Further research is highly recommended to determine the most functional formula, dose, duration, and possible side effects of curcumin on mental disorders in humans. Based on the current knowledge, the curcumin nanoformulation and Theracurmin, a form of colloidal submicroscopic particles, seem to be the most effective bioavailable formulations, which may be examined in future clinical human studies.

Adverse childhood experience and depression: the role of gut microbiota

Depression is the most common psychiatric disorder that burdens modern society heavily. Numerous studies have shown that adverse childhood experiences can increase susceptibility to depression, and depression with adverse childhood experiences has specific clinical-biological features. However, the specific neurobiological mechanisms are not yet precise. Recent studies suggest that the gut microbiota can influence brain function and behavior associated with depression through the "microbe-gut-brain axis" and that the composition and function of the gut microbiota are influenced by early stress. These studies offer a possibility that gut microbiota mediates the relationship between adverse childhood experiences and depression. However, few studies directly link adverse childhood experiences, gut microbiota, and depression. This article reviews recent studies on the relationship among adverse childhood experiences, gut microbiota, and depression, intending to provide insights for new research.

The neurobiological effects of senescence on dopaminergic system: A comprehensive review

Over time, the body undergoes a natural, multifactorial, and ongoing process named senescence, which induces changes at the molecular, cellular, and micro-anatomical levels in many body systems. The brain, being a highly complex organ, is particularly affected by this process, potentially impairing its numerous functions. The brain relies on chemical messengers known as neurotransmitters to function properly, with dopamine being one of the most crucial. This catecholamine is responsible for a broad range of critical roles in the central nervous system, including movement, learning, cognition, motivation, emotion, reward, hormonal release, memory consolidation, visual performance, sexual drive, modulation of circadian rhythms, and brain development. In the present review, we thoroughly examine the impact of senescence on the dopaminergic system, with a primary focus on the classic delimitations of the dopaminergic nuclei from A8 to A17. We provide in-depth information about their anatomy and function, particularly addressing how senescence affects each of these nuclei.

The monoaminergic pathways are involved in the antidepressant-like effect of quercetin

Quercetin, a plant-derived flavonoid, is an antioxidant and has demonstrated antidepressant and anti-inflammatory activities in several animal models. However, there is scanty information on the underlying mechanisms of its antidepressant property. This present study aimed at assessing the involvement of monoaminergic systems in the antidepressant-like activity of quercetin in experimental animals. Mice received varying doses of quercetin (25, 50 &100 mg/kg daily) and were then subjected to open field test (OPF), despair tests, the reserpine test, and the yohimbine lethality test (YLT). In addition, monoaminergic involvement was investigated by combining quercetin (100 mg/kg) with dopaminergic antagonists (haloperidol and sulpiride), adrenergic blockers (prazosin, propranolol and yohimbine), and serotonergic blockers/inhibitors (metergoline). The results showed that quercetin produced significant anti-immobility effects in the forced swim test (FST) and tail suspension test (TST), suggesting antidepressant activity. In addition, the potentiation of yohimbine lethality by quercetin further indicates its antidepressant-like property. This antidepressant action demonstrated was, however, blocked when quercetin was co-administered with dopaminergic, adrenergic and serotonergic antagonists, suggesting involvement of the monoaminergic system in the antidepressant action of quercetin. Nevertheless, quercetin did not significantly alter the locomotor activity of mice, which implies lack of stimulant effect. Taken together, these outcomes suggest that monoaminergic systems are likely involved in the anti-depressant effect of quercetin in mice.

Neuromelanin-sensitive magnetic resonance imaging in the study of mental disorder: A systematic review

Dopamine and norepinephrine are implicated in the pathophysiology of mental disorders, but non-invasive study of their neuronal function remains challenging. Recent research suggests that neuromelanin-sensitive magnetic resonance imaging (NM-MRI) techniques may overcome this limitation by enabling the non-invasive imaging of the substantia nigra (SN)/ ventral tegmental area (VTA) dopaminergic and locus coeruleus (LC) noradrenergic systems. A review of 19 studies that met the criteria for NM-MRI application in mental disorders found that despite the use of heterogeneous sequence parameters and metrics, nearly all studies reported differences in contrast ratio (CNR) of LC or SN/VTA between patients with mental disorders and healthy controls. These findings suggest that NM-MRI is a valuable tool in psychiatry, but the differences in sequence parameters across studies hinder comparability, and a standardized analysis pipeline is needed to improve the reliability of results. Further research using standardized methods is needed to better understand the role of dopamine and norepinephrine in mental disorders.

Safety and tolerance of combination of monoamine oxidase inhibitors and direct dopamine agonists in adults and older adults with highly resistant depression

INTRODUCTION

Dopamine (DA) is likely to be involved in some depressive dimensions, such as anhedonia and amotivation, which account for a part of treatment-resistant forms. Monoamine oxidase inhibitors (MAOI) and direct D2 and D3 receptors agonists (D2/3r-dAG) are known to help, but we lack safety data about their combined usage. We report on safety and tolerance of the MAOI+D2r-dAG combination in a clinical series.

METHOD

All patients referred to our recourse center for depression between 2013 and 2021 were screened to select those who did receive the combo. Data were extracted from clinical files.

RESULTS

Sixteen patients of 60±17 years of age (8 women, 7 with age>65years, all suffered from treatment resistant depression, 7 with bipolar disorder) received the combo. There were no life-threatening adverse effects (AE). However, AE were reported by 14 patients (88%) most of which were mild and consisted of insomnia, nausea, nervousness, confusion, impulse control disorder and/or "sleep attacks". One patient presented a serious AE requiring a short hospitalization for confusion. Intolerance led to failure to introduce treatment in two patients (13%). The retrospective non-interventional design, the variety of molecules, and the modest sample size limited the scope of these results.

CONCLUSION

There was no life-threatening safety issue in combining MAOI and D2/3r-dAG, especially regarding cardiovascular side effects. The systematic screening of AE might account for their frequency, but these precluded the treatment in only two patients. Comparative studies are needed to assess the efficacy of this new combination.

The Formation and Function of the VTA Dopamine System

The midbrain dopamine system is a sophisticated hub that integrates diverse inputs to control multiple physiological functions, including locomotion, motivation, cognition, reward, as well as maternal and reproductive behaviors. Dopamine is a neurotransmitter that binds to G-protein-coupled receptors. Dopamine also works together with other neurotransmitters and various neuropeptides to maintain the balance of synaptic functions. The dysfunction of the dopamine system leads to several conditions, including Parkinson's disease, Huntington's disease, major depression, schizophrenia, and drug addiction. The ventral tegmental area (VTA) has been identified as an important relay nucleus that modulates homeostatic plasticity in the midbrain dopamine system. Due to the complexity of synaptic transmissions and input-output connections in the VTA, the structure and function of this crucial brain region are still not fully understood. In this review article, we mainly focus on the cell types, neurotransmitters, neuropeptides, ion channels, receptors, and neural circuits of the VTA dopamine system, with the hope of obtaining new insight into the formation and function of this vital brain region.

Decoding Post-Viral Fatigue: The Basal Ganglia's Complex Role in Long-COVID

Long-COVID afflicts millions with relentless fatigue, disrupting daily life. The objective of this narrative review is to synthesize current evidence on the role of the basal ganglia in long-COVID fatigue, discuss potential mechanisms, and highlight promising therapeutic interventions. A comprehensive literature search was conducted using PubMed, Scopus, and Web of Science databases. Mounting evidence from PET, MRI, and functional connectivity data reveals basal ganglia disturbances in long-COVID exhaustion, including inflammation, metabolic disruption, volume changes, and network alterations focused on striatal dopamine circuitry regulating motivation. Theories suggest inflammation-induced signaling disturbances could impede effort/reward valuation, disrupt cortical-subcortical motivational pathways, or diminish excitatory input to arousal centers, attenuating drive initiation. Recent therapeutic pilots targeting basal ganglia abnormalities show provisional efficacy. However, heterogeneous outcomes, inconsistent metrics, and perceived versus objective fatigue discrepancies temper insights. Despite the growing research, gaps remain in understanding the precise pathways linking basal ganglia dysfunction to fatigue and validating treatment efficacy. Further research is needed to advance understanding of the basal ganglia's contribution to long-COVID neurological sequelae and offer hope for improving function across the expanding affected population.

The impact of estradiol on serotonin, glutamate, and dopamine systems

Estradiol, the most potent and prevalent member of the estrogen class of steroid hormones and is expressed in both sexes. Functioning as a neuroactive steroid, it plays a crucial role in modulating neurotransmitter systems affecting neuronal circuits and brain functions including learning and memory, reward and sexual behaviors. These neurotransmitter systems encompass the serotonergic, dopaminergic, and glutamatergic signaling pathways. Consequently, this review examines the pivotal role of estradiol and its receptors in the regulation of these neurotransmitter systems in the brain. Through a comprehensive analysis of current literature, we investigate the multifaceted effects of estradiol on key neurotransmitter signaling systems, namely serotonin, dopamine, and glutamate. Findings from rodent models illuminate the impact of hormone manipulations, such as gonadectomy, on the regulation of neuronal brain circuits, providing valuable insights into the connection between hormonal fluctuations and neurotransmitter regulation. Estradiol exerts its effects by binding to three estrogen receptors: estrogen receptor alpha (ERα), estrogen receptor beta (ERβ), and G protein-coupled receptor (GPER). Thus, this review explores the promising outcomes observed with estradiol and estrogen receptor agonists administration in both gonadectomized and/or genetically knockout rodents, suggesting potential therapeutic avenues. Despite limited human studies on this topic, the findings underscore the significance of translational research in bridging the gap between preclinical findings and clinical applications. This approach offers valuable insights into the complex relationship between estradiol and neurotransmitter systems. The integration of evidence from neurotransmitter systems and receptor-specific effects not only enhances our understanding of the neurobiological basis of physiological brain functioning but also provides a comprehensive framework for the understanding of possible pathophysiological mechanisms resulting to disease states. By unraveling the complexities of estradiol's impact on neurotransmitter regulation, this review contributes to advancing the field and lays the groundwork for future research aimed at refining understanding of the relationship between estradiol and neuronal circuits as well as their involvement in brain disorders.

Associations of anxiety and depression with restless leg syndrome: a systematic review and meta-analysis

Background

The levels of anxiety and depression among patients with restless leg syndrome (RLS) are controversial. The aim of this systematic review and meta-analysis was to compare the levels of depression and anxiety among individuals with RLS with those of healthy controls.

Methods

We conducted an extensive electronic search of the PubMed, Web of Science, EMBASE, and Cochrane Library databases from their inception dates to 20 June 2023. Studies presenting data on depression and anxiety in individuals with RLS were included, and a comprehensive meta-analysis was performed.

Results

Twenty-one studies matched the inclusion criteria. Significantly more depressive symptoms were present in the individuals with RLS than in those without RLS, as measured by the Beck Depression Inventory [mean difference (MD) = 6.58, 95% confidence interval (CI) = 5.54-7.62, p < 0.01; heterogeneity I2 = 0%, p = 0.99]. Similarly, the results from the Beck Anxiety Inventory indicated that there were significantly more pronounced anxiety symptoms in the individuals with RLS than in those without RLS (MD = 9.30, 95%CI = 7.65-10.94, p < 0.01; heterogeneity I2 = 0%, p = 0.92). The other anxiety and depression scales also yielded statistically significant results. Significant heterogeneity was observed in the Hamilton Depression Rating Scale and Hamilton Anxiety Rating Scale, with the primary contributing factor probably being the scoring criteria of the scales.

Conclusion

This meta-analysis found that the levels of depression and anxiety symptoms were significantly higher in individuals with RLS than in their healthy counterparts.Systematic review registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023410364, (identifier CRD42023410364).

Major Depressive Disorder as a Driver of Dual Systems Model Development During Adolescence and Emerging Adulthood Among Justice-Involved Youth: Is Salience Age-Graded?

The dual systems model is a psychological framework centered on differential development of sensation-seeking and impulse control during adolescence and emerging adulthood with implications for understanding antisocial behavior. However, there is a dearth of research which has examined mental illness as a driver of differential development of these constructs. This study examined major depressive disorder as a risk factor for elevated sensation-seeking and diminished impulse control and tested to determine whether the salience differed by age. The Pathways to Desistance data were analyzed. Mixed effects models examined the direct effect of major depressive disorder on dual systems outcomes and test for moderation by age. Findings indicated that major depressive disorder at baseline was associated with increased sensation-seeking and diminished impulse control. Relationships did not differ in salience based on age. Results suggest that treatment effective for addressing depression may have relevance for mitigating the impact of the disorder on cognition.

Phosphoproteomics implicates glutamatergic and dopaminergic signalling in the antidepressant-like properties of the iron chelator deferiprone

BACKGROUND

Current antidepressants have limitations due to insufficient efficacy and delay before improvement in symptoms. Polymorphisms of the serotonin transporter (5-HTT) gene have been linked to depression (when combined with stressful life events) and altered response to selective serotonergic reuptake inhibitors. We have previously revealed the antidepressant-like properties of the iron chelator deferiprone in the 5-HTT knock-out (KO) mouse model of depression. Furthermore, deferiprone was found to alter neural activity in the prefrontal cortex of both wild-type (WT) and 5-HTT KO mice.

METHODS

In the current study, we examined the molecular effects of acute deferiprone treatment in the prefrontal cortex of both genotypes via phosphoproteomics analysis.

RESULTS

In WT mice treated with deferiprone, there were 22 differentially expressed phosphosites, with gene ontology analysis implicating cytoskeletal proteins. In 5-HTT KO mice treated with deferiprone, we found 33 differentially expressed phosphosites. Gene ontology analyses revealed phosphoproteins that were predominantly involved in synaptic and glutamatergic signalling. In a drug-naïve cohort (without deferiprone administration), the analysis revealed 21 differentially expressed phosphosites in 5-HTT KO compared to WT mice. We confirmed the deferiprone-induced increase in tyrosine hydroxylase serine 40 residue phosphorylation (pTH-Ser40) (initially revealed in our phosphoproteomics study) by Western blot analysis, with deferiprone increasing pTH-Ser40 expression in WT and 5-HTT KO mice.

CONCLUSION

As glutamatergic and synaptic signalling are dysfunctional in 5-HTT KO mice (and are the target of fast-acting antidepressant drugs such as ketamine), these molecular effects may underpin deferiprone's antidepressant-like properties. Furthermore, dopaminergic signalling may also be involved in deferiprone's antidepressant-like properties.

Epistasis in neurotransmitter receptors linked to posttraumatic stress disorder and major depressive disorder comorbidity in traumatized Chinese

Background

Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) comorbidity occurs through exposure to trauma with genetic susceptibility. Neuropeptide-Y (NPY) and dopamine are neurotransmitters associated with anxiety and stress-related psychiatry through receptors. We attempted to explore the genetic association between two neurotransmitter receptor systems and the PTSD-MDD comorbidity.

Methods

Four groups were identified using latent profile analysis (LPA) to examine the patterns of PTSD and MDD comorbidity among survivors exposed to earthquake-related trauma: low symptoms, predominantly depression, predominantly PTSD, and PTSD-MDD comorbidity. NPY2R (rs4425326), NPY5R (rs11724320), DRD2 (rs1079597), and DRD3 (rs6280) were genotyped from 1,140 Chinese participants exposed to earthquake-related trauma. Main, gene-environment interaction (G × E), and gene-gene interaction (G × G) effects for low symptoms, predominantly depression, and predominantly PTSD were tested using a multinomial logistic model with PTSD-MDD comorbidity as a reference.

Results

The results demonstrated that compared to PTSD-MDD comorbidity, epistasis (G × G) NPY2R-DRD2 (rs4425326 × rs1079597) affects low symptoms (β = -0.66, OR = 0.52 [95% CI: 0.32-0.84], p = 0.008, pperm = 0.008) and predominantly PTSD (β = -0.56, OR = 0.57 [95% CI: 0.34-0.97], p = 0.037, pperm = 0.039), while NPY2R-DRD3 (rs4425326 × rs6280) impacts low symptoms (β = 0.82, OR = 2.27 [95% CI: 1.26-4.10], p = 0.006, pperm = 0.005) and predominantly depression (β = 1.08, R = 2.95 [95% CI: 1.55-5.62], p = 0.001, pperm = 0.001). The two G × G effects are independent.

Conclusion

NPY and dopamine receptor genes are related to the genetic etiology of PTSD-MDD comorbidity, whose specific mechanisms can be studied at multiple levels.

Quantification of Plasma Dopamine in Depressed Patients Using Silver-Enriched Silicon Nanowires as SERS-Active Substrates

A decrease in the levels of dopamine (DA)─a key catecholamine biomarker for major depressive disorder─highlights the need for quantitative analysis of biological fluids to aid in the early diagnosis of diverse neuropsychiatric disorders. This study developed silicon nanowires enriched with silver nanoparticles to serve as a surface-enhanced Raman scattering (SERS) substrate to enable precise and sensitive quantification of blood plasma DA levels in humans. The silver-enriched silicon nanowires (SiNWs@Ag) yielded flower-like assemblies with densely populated SERS "hot spots," allowing sensitive DA detection. By correlating DA concentration with Raman intensity at 1156 cm-1, the plasma DA levels in treatment-naïve patients with major depression (n = 18) were 2 orders of magnitude lower than those in healthy controls (n = 18) (6.56 × 10-10 M vs 1.43 × 10-8 M). The plasma DA concentrations differed significantly between the two groups (two-tailed p = 5.77×10-7), highlighting a distinct demarcation between depression patients and healthy controls. Furthermore, the SiNWs@Ag substrate effectively differentiated between DA and norepinephrine (NE) in mixtures at nanomolar levels, demonstrating its selective detection capability. This study represents the first report on the quantitative detection of DA levels in human blood samples from individuals with major depression using an SERS technique, emphasizing its potential clinical utility in the evaluation and diagnosis of neuropsychiatric disorders.

Effect of MCH1, a fatty-acid amide hydrolase inhibitor, on the depressive-like behavior and gene expression of endocannabinoid and dopaminergic-signaling system in the mouse nucleus accumbens

MCH1 is a synthetic macamide that has shown in vitro inhibitory activity on fatty acid amide hydrolase (FAAH), an enzyme responsible for endocannabinoid metabolism. This inhibition can modulate endocannabinoid and dopamine signaling in the nucleus accumbens (NAc), potentially having an antidepressant-like effect. The present study aimed to evaluate the effect of the in vivo administration of MCH1 (3, 10, and 30 mg/kg, ip) in 2-month-old BALB/c male mice (n=97) on forced swimming test (FST), light-dark box (LDB), and open field test (OFT) and on early gene expression changes 2 h after drug injection related to the endocannabinoid system (Cnr1 and Faah) and dopaminergic signaling (Drd1 and Drd2) in the NAc core. We found that the 10 mg/kg MCH1 dose reduced the immobility time compared to the vehicle group in the FST with no effect on anxiety-like behaviors measured in the LDB or OFT. However, a 10 mg/kg MCH1 dose increased locomotor activity in the OFT compared to the vehicle. Moreover, RT-qPCR results showed that the 30 mg/kg MCH1 dose increased Faah gene expression by 2.8-fold, and 10 mg/kg MCH1 increased the Cnr1 gene expression by 4.3-fold compared to the vehicle. No changes were observed in the expression of the Drd1 and Drd2 genes in the NAc at either MCH1 dose. These results indicated that MCH1 might have an antidepressant-like effect without an anxiogenic effect and induces significant changes in endocannabinoid-related genes but not in genes of the dopaminergic signaling system in the NAc of mice.

A review of the pharmacological action and mechanism of natural plant polysaccharides in depression

Depression is a prevalent mental disorder. However, clinical treatment options primarily based on chemical drugs have demonstrated varying degrees of adverse reactions and drug resistance, including somnolence, nausea, and cognitive impairment. Therefore, the development of novel antidepressant medications that effectively reduce suffering and side effects has become a prominent area of research. Polysaccharides are bioactive compounds extracted from natural plants that possess diverse pharmacological activities and medicinal values. It has been discovered that polysaccharides can effectively mitigate depression symptoms. This paper provides an overview of the pharmacological action and mechanisms, intervention approaches, and experimental models regarding the antidepressant effects of polysaccharides derived from various natural sources. Additionally, we summarize the roles and potential mechanisms through which these polysaccharides prevent depression by regulating neurotransmitters, HPA axis, neurotrophic factors, neuroinflammation, oxidative stress, tryptophan metabolism, and gut microbiota. Natural plant polysaccharides hold promise as adjunctive antidepressants for prevention, reduction, and treatment of depression by exerting their therapeutic effects through multiple pathways and targets. Therefore, this review aims to provide scientific evidence for developing polysaccharide resources as effective antidepressant drugs.

Antidepressant-like Effect of the Eburnamine-Type Molecule Vindeburnol in Rat and Mouse Models of Ultrasound-Induced Depression

Vindeburnol (VIND, RU24722, BC19), a synthetic molecule derived from the eburnamine-vincamine alkaloid group, has many neuropsychopharmacological effects, but its antidepressant-like effects are poorly understood and have only been described in a few patents. To reliably estimate this effect, vindeburnol was studied in a model of long-term variable-frequency ultrasound (US) exposure at 20-45 kHz in male Wistar rats and BALB/c mice. Vindeburnol was administered chronically for 21 days against a background of simultaneous ultrasound exposure at a dose of 20 mg/kg intraperitoneally (IP). Using four behavioral tests, the sucrose preference test (SPT), the social interaction test (SIT), the open field test (OFT), and the forced swimming test (FST), we found that the treatment with the compound diminished depression-like symptoms in mice and rats. The compound restored the ultrasound-related reduced sucrose consumption to control levels and increased social interaction time in mice and rats compared with those in ultrasound-exposed animals. Vindeburnol showed contraversive results of horizontal and vertical activity in both species and generally did not increase locomotor activity. At the same time, the compound showed a specific effect in the FST, significantly reducing the immobility time. Moreover, we found an increase in norepinephrine, dopamine, and its metabolite levels in the brainstem, as well as an increase in dopamine, 3-methoxytyramine, and 3,4-dihydroxyphenylacetic acid levels in the striatum. We also observed a statistically significant increase in tyrosine hydroxylase (TH) levels in the region containing the locus coeruleus (LC). We suggest that using its distinct chemical structure and pharmacological activity as a starting point could boost antidepressant drug discovery.

Association between secondhand smoke exposure across the life course and depressive symptoms among Chinese older adults

BACKGROUND

There are limited data on the association between secondhand smoke (SHS) exposure across the life course and depressive symptoms among older adults. We aimed to investigate the association of childhood household SHS exposure, adulthood household SHS exposure, lifetime social SHS exposure, and their coexistence with depressive symptoms in older adults.

METHODS

Data were from the 2011-2012 and 2014 waves of the Chinese Longitudinal Healthy Longevity Survey. About 4000 participants (aged 60 years or older) were recruited in a randomly selected half of the counties and cities in China. Data on SHS exposure, past-year depressive symptoms, and covariates were collected using a questionnaire. The chi-square test (for categorical variables) and t-test (for continuous variables) were used to assess differences in the participant characteristics across groups of SHS exposures. We estimated the odds ratios (ORs) and 95 % confidence intervals (CIs) of depressive symptom according to different types of SHS exposure.

RESULTS

Childhood household SHS exposure (OR = 1.42, 95%CI = 1.22-1.66), adulthood household SHS exposure (OR = 1.41, 95%CI = 1.21-1.63) and lifetime social SHS exposure (OR = 1.35, 95%CI = 1.14-1.58) were associated with higher odds of depressive symptoms. Additionally, those with a higher SHS exposure score had higher odds of depressive symptoms (1 point: OR = 1.56, 95%CI = 1.22-2.00; 2 points: OR = 1.77, 95%CI = 1.39-2.25; 3 points: OR = 1.83, 95%CI = 1.45-2.31). The results were similar when stratified by lifetime nonsmoking, former smoking, and current smoking.

LIMITATIONS

Retrospective design may introduce recall bias.

CONCLUSIONS

SHS exposure was associated with higher odds of depressive symptoms in older adults, with the effect seeming to be addictive.

Using rodent data to elucidate dopaminergic mechanisms of ADHD: Implications for human personality

An altered behavioral response to positive reinforcement has been proposed to be a core deficit in attention deficit hyperactivity disorder (ADHD). The spontaneously hypertensive rat (SHR), a congenic animal strain, displays a similarly altered response to reinforcement. The presence of this genetically determined phenotype in a rodent model allows experimental investigation of underlying neural mechanisms. Behaviorally, the SHR displays increased preference for immediate reinforcement, increased sensitivity to individual instances of reinforcement relative to integrated reinforcement history, and a steeper delay of reinforcement gradient compared to other rat strains. The SHR also shows less development of incentive to approach sensory stimuli, or cues, that predict reward after repeated cue-reward pairing. We consider the underlying neural mechanisms for these characteristics. It is well known that midbrain dopamine neurons are initially activated by unexpected reward and gradually transfer their responses to reward-predicting cues. This finding has inspired the dopamine transfer deficit (DTD) hypothesis, which predicts certain behavioral effects that would arise from a deficient transfer of dopamine responses from actual rewards to reward-predicting cues. We argue that the DTD predicts the altered responses to reinforcement seen in the SHR and individuals with ADHD. These altered responses to reinforcement in turn predict core symptoms of ADHD. We also suggest that variations in the degree of dopamine transfer may underlie variations in personality dimensions related to altered reinforcement sensitivity. In doing so, we highlight the value of rodent models to the study of human personality.

One-drop chemosensing of dapoxetine hydrochloride using opto-analysis by multi-channel μPAD decorated silver nanoparticles: introducing a paper-based microfluidic portable device/sensor toward naked-eye pharmaceutical analysis by lab-on-paper technology

Dapoxetine (DPX) belongs to the selective serotonin reuptake inhibitor (SSRI) class and functions by blocking the serotonin transporter and increasing serotonin activity, thereby delaying ejaculation. Therefore, monitoring of the concentration of DPX in human biofluids is important for clinicians. In this study, application of silver nanoparticles with the morphology of prisms (AgNPrs) for the sensitive measurement of DPX using colorimetric chemosensing and the spectrophotometric method was investigated. Also, DPX was determined in real samples using the spectrophotometry method. Based on the obtained results, all of the detection process in colorimetric assay is related to morphological reform of AgNPrs after it's specific electrostatic and covalent interaction with DPX as analyte. The UV-vis results indicate that the proposed AgNPrs-based chemosensing system has a wide range of linearity (0.01 μM to 1 mM) with a low limit of quantification of 0.01 μM in human urine samples, which is suitable for clinical analysis of this drug in human urine samples. It is important to point out that, this chemosensing strategy showed inappropriate analytical results for the detection of DPX in human urine samples which is a novelty of this platform. Finally, the optimized microfluidic paper-based analytical device (μPAD) was integrated with the colorimetric analysis of DPX to provide a time/color system for estimating analyte concentration by a portable substrate toward in situ and on-site biomedical analysis. Interestingly, the analytical validation tests showed appropriate results with great stability, which may facilitate commercialization of the engineered substrate. For the first time, in order to provide a simple and portable colorimetric/spectrophotometric recognition system to sensitive determination of DPX, an optimized pump-less microfluidic paper-based colorimetric device (μPCD) was introduced and validated for the real-time biomedical analysis of this analyte. According to the obtained results, this alternative approach is suitable for therapeutic drug monitoring (TDM) and biomedical analysis by miniaturized and cost-beneficial devices.

Aesthetic chills mitigate maladaptive cognition in depression

BACKGROUND

Depression is a major global health challenge, affecting over 300 million people worldwide. Current pharmacological and psychotherapeutic interventions have limited efficacy, underscoring the need for novel approaches. Emerging evidence suggests that peak emotional experiences characterized by awe, transcendence, and meaning hold promise for rapidly shifting maladaptive cognitive patterns in depression. Aesthetic chills, a peak positive emotion characterized by physical sensations such as shivers and goosebumps, may influence reward-related neural pathways and hold promise for modifying core maladaptive beliefs rooted in early adverse experiences.

METHODS

We enrolled 96 patients diagnosed with major depressive disorder. A validated database of multimedia known to elicit chills responses (ChillsDB) was used for stimulus presentation. Participants' emotional responses were assessed using the Emotional Breakthrough Inventory (EBI), while shifts in self-schema were measured via the Young Positive Schema Questionnaire (YSPQ).

RESULTS

The study found that chill-inducing stimuli have the potential to positively influence the core schema of individuals with depression, impacting areas of self-related beliefs. The associated phenomenology triggered by chills appears to share similarities with the altered states of consciousness induced by psychedelic substances like psilocybin.

CONCLUSIONS

These preliminary results suggest that the biological processes involved in aesthetic chills could be harnessed as a non-pharmacological intervention for depression. However, further investigation is necessary to comprehensively understand the neurophysiological responses to chills and to evaluate the practicality, effectiveness, and safety of utilizing aesthetic chills as a preventive measure in mental health care.

Dopamine pathways mediating affective state transitions after sleep loss

The pathophysiology of affective disorders-particularly circuit-level mechanisms underlying bidirectional, periodic affective state transitions-remains poorly understood. In patients, disruptions of sleep and circadian rhythm can trigger transitions to manic episodes, whereas depressive states are reversed. Here, we introduce a hybrid automated sleep deprivation platform to induce transitions of affective states in mice. Acute sleep loss causes mixed behavioral states, featuring hyperactivity, elevated social and sexual behaviors, and diminished depressive-like behaviors, where transitions depend on dopamine (DA). Using DA sensor photometry and projection-targeted chemogenetics, we reveal that elevated DA release in specific brain regions mediates distinct behavioral changes in affective state transitions. Acute sleep loss induces DA-dependent enhancement in dendritic spine density and uncaging-evoked dendritic spinogenesis in the medial prefrontal cortex, whereas optically mediated disassembly of enhanced plasticity reverses the antidepressant effects of sleep deprivation on learned helplessness. These findings demonstrate that brain-wide dopaminergic pathways control sleep-loss-induced polymodal affective state transitions.

Neuroplasticity: Pathophysiology and Role in Major Depressive Disorder

Neuroplasticity is characterized by the brain's ability to change its activity in response to extrinsic and intrinsic factors and is thought to be the mechanism behind all brain functions. Neuroplasticity causes structural and functional changes on a molecular level, specifically the growth of different regions in the brain and changes in synaptic and post-synaptic activities. The four types of neuroplasticity are homologous area adaption, compensatory masquerade, cross-modal reassignment, and map expansion. All of these help the brain work around injuries or new information inputs. In addition to baseline physical functions, neuroplasticity is thought to be the basis of emotional and mental regulations and the impairment of it can cause various mental illnesses. Concurrently, these mental illnesses further the damage of synaptic plasticity in the brain. Major depressive disorder (MDD) is one of the most common mental illnesses. It is affected by and accelerates the impairment of neuroplasticity. It is characterized by a chronically depressed state of mind that can impact the patient's daily life, including work life and interests. This review will focus on highlighting the physiological aspects of the disease and the role of neuroplasticity in the pathogenesis and pathology of the disorder. Moreover, the role of monoamine regulation and ketamine uptake will be discussed in terms of their antidepressant effects on the outcomes of MDD.

Determination of intracellular dopamine by liquid chromatography-fluorescence detection with post-column derivatization using the König reaction

Dopamine is an important neurotransmitter, and the disruption of dopaminergic homeostasis causes various neurological diseases such as Parkinson's disease. Analysis of intracellular dopamine levels is important to understand the pathology of neurological diseases. We have developed a new method for the fluorometric detection of dopamine by adopting the König reaction, which is commonly used for the detection of cyanide, thiocyanate, and selenocyanate, and demonstrated that it can be applied to the determination of intracellular dopamine levels. The present method only requires a conventional LC system with isocratic elution and post-column derivatization and is simple to perform. The LOD, LOQ, and linearity range were 10.8 nM, 32.8 nM, and 0.05-10 μM, respectively, with accuracies of 101.8-106.3 % and precisions within 5 %, which are sufficient for the quantification of intracellular dopamine. We also determined dopamine levels in PC12 cells and found that the levels increased and decreased when the cells were exposed to L-dopa and cyanide, respectively, possibly because of the conversion of L-dopa into dopamine and the depletion of intracellular dopamine by exposing cells to cyanide, respectively. These results suggest the applicability of the present method, and that this new use of the König reaction offers a reliable and useful means of quantifying intracellular dopamine.

Psychopharmacological Approaches for Neural Plasticity and Neurogenesis in Major Depressive Disorders

Major depressive disorder (MDD) is a mental health disorder associated with cognitive impairment, dysregulated appetite, fatigue, insomnia or hypersomnia, and severe mood changes that significantly impact the ability of the affected individual to perform day-to-day tasks, leading to suicide in the worst-case scenario. As MDD is becoming more prevalent, affecting roughly 300 million individuals worldwide, its treatment has become a major point of interest. Antidepressants acting as selective serotonin reuptake inhibitors (SSRIs) are currently used as the first line of treatment for MDD. Other antidepressants currently used for the treatment of MDD include the serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs). However, although effective in alleviating symptoms of MDD, most antidepressants require weeks or even months of regular administration prior to eliciting a rational clinical effect. Owing to the strong evidence showing a relationship between neural plasticity, neurogenesis, and MDD, researchers have also looked at the possibility of using treatment modalities that target these processes in an attempt to improve clinical outcome. The overarching aim of this chapter is to highlight the role of neural plasticity and neurogenesis in the pathophysiology of MDD and discuss the most recently studied treatment strategies that target these processes by presenting supporting evidence from both animal and human studies.

The Gut Microbiota and Major Depressive Disorder: Current Understanding and Novel Therapeutic Strategies

Major depressive disorder (MDD) is a common neuropsychiatric challenge that primarily targets young females. MDD as a global disorder has a multifactorial etiology related to the environment and genetic background. A balanced gut microbiota is one of the most important environmental factors involved in human physiological health. The interaction of gut microbiota components and metabolic products with the hypothalamic-pituitary-adrenal system and immune mediators can reverse depression phenotypes in vulnerable individuals. Therefore, abnormalities in the quantitative and qualitative structure of the gut microbiota may lead to the progression of MDD. In this review, we have presented an overview of the bidirectional relationship between gut microbiota and MDD, and the effect of pre-treatments and microbiomebased approaches, such as probiotics, prebiotics, synbiotics, fecal microbiota transplantation, and a new generation of microbial alternatives, on the improvement of unstable clinical conditions caused by MDD.

Differences in the prevalence and clinical correlates of depressive symptoms in male patients with methamphetamine and heroin use disorder in a Chinese Han population

BACKGROUND AND OBJECTIVES

Comorbidity of substance use disorders and depression is a common phenomenon. It is well known that opioid addiction is neurobiologically distinct from psychostimulant addiction. However, direct comparisons of comorbid depressive symptoms in patients with methamphetamine (METH) use disorder (MAUD) and heroin use disorders (HUD) have been lacking until now.

METHODS

A total of 353 patients with methamphetamine use disorder, 76 patients with HUD, and 203 healthy controls were recruited. The Beck Depression Inventory (BDI-SF), the Desires for Drug Questionnaire (DDQ) and the short form of the Childhood Trauma Questionnaire (CTQ-SF) were used to measure participants' depressive symptoms, drug craving, and childhood abuse or neglect, respectively.

RESULTS

The prevalence of depressive symptoms was 35.41% (125/353) in MAUD and 56.57% (43/76) in MAUD, significantly higher than the 22.66% (46/203) in healthy controls. Furthermore, there was a significant difference in the total BDI score between the MAUD and HUD groups (F = 5.02, df = 1, 372, p = .026). Among MAUD, years of education, history of incarceration, month of abstinence and negative reinforcement scores were associated with depressive symptoms (all p < .05). Among HUD, duration of drug use, childhood emotional abuse and sexual abuse were associated with depressive symptoms (all p < .05).

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

The prevalence and correlates of depressive symptoms differ between MAUD and HUD, adding to the existing literature. Therefore, treatment and intervention programs should be designed to address these unique correlates in HUD and MAUD patients.

Berberine exerts antidepressant effects in vivo and in vitro through the PI3K/AKT/CREB/BDNF signaling pathway

BACKGROUND

Depression, a global neuropsychiatric disorder, brings a serious burden to patients and society as its incidence continues to rise. Berberine is one of the main compounds of a variety of Chinese herbal medicines and has been shown to have multiple pharmacological effects. However, whether berberine can exert antidepressant effects in vivo and in vitro and its related mechanisms remain to be explored.

METHODS

The chronic restraint stress (CRS) method and corticosterone (CORT) were applied to simulate depression-like behavior in vivo and neuronal apoptosis in vitro, respectively. The antidepressant effects of berberine were evaluated by behavioral tests and changes in the content of monoamine neurotransmitters. Inflammatory cytokines were detected and immunofluorescence staining was used to observe the expression levels of apoptosis-related proteins. RT-qPCR and Western blot were used to examine the mRNA and protein expression (or phosphorylation) levels of biomarkers of the PI3K/AKT/CREB/BDNF signaling pathways.

RESULTS

Behavioral tests and levels of neurotransmitters proved that berberine could effectively ameliorate depression-like symptoms in CRS mice. Meanwhile, the results of ELISA and immunofluorescence staining showed that berberine could alleviate inflammatory status and reduce cell apoptosis in vivo and in vitro. Moreover, the changes of the PI3K/AKT/CREB/BDNF signaling pathway induced by CRS or CORT in mouse hippocampus or HT-22 cells were significantly reversed by berberine.

CONCLUSION

Our current study suggested that berberine could exert antidepressant effects in vitro and in vivo, which may be associated with the PI3K/AKT/CREB/BDNF signaling pathway.

Stimulatory and Inhibitory Effect of Antipsychotic Agents Including Dopaminergic Neuro-depressants on Dopamine Formation from p-tyramine Mediated by Cytochrome P450 2D6

BACKGROUND AND OBJECTIVES

The effects of antipsychotic agents, including dopamine D2 receptor blocking agents such as haloperidol, chlorpromazine, and sulpiride, and related compounds such as mirtazapine and sertraline, on dopamine formation from p-tyramine catalyzed by cytochrome P450 (CYP) 2D6.2 (Arg296Cys;Ser486Thr), CYP2D6.10 (Pro34Ser;Ser486Thr), and CYP2D6.39 (Ser486Thr) were compared with those of CYP2D6.1.

METHODS

Dopamine was determined by high-performance liquid chromatography, and Michaelis constants (Km), maximal velocity (kcat) values for dopamine formation, and inhibition constants (Ki) of psychotropic agents were estimated.

RESULTS

Km values for all CYP2D6 variants decreased at lower concentrations, and kcat values for CYP2D6 variants except for CYP2D6.10 gradually increased with increasing haloperidol concentrations up to 5 or 10 μM. The kcat/Km values for all CYP2D6 variants increased at under 2.5 μM concentrations. Lower sertraline concentrations decreased Km values for CYP2D6.10. Chlorpromazine at concentrations under 10 μM competitively inhibited the activities catalyzed by all variants; however, the activities for only CYP2D6.10 were increased by chlorpromazine at concentrations over 250 μM. Mirtazapine and sertraline similarly decreased dopamine formation among all variants except for CYP2D6.10. However, CYP2D6.10 inhibition by mirtazapine was weaker than that of the other variants, and sertraline decreased Km values for CYP2D6.10.

CONCLUSION

Haloperidol and sertraline, but not sulpiride, decreased the Km and/or increased kcat values for CYP2D6. The present findings suggest that Dopamine D2 receptor-blocking agents and related compounds may polymorphically affect dopamine formation catalyzed by CYP2D6 in the brain.

Biomarkers of Affective Dysregulation Associated with In Utero Exposure to EtOH

INTRODUCTION

Children with fetal alcohol spectrum disorders (FASD) exhibit behavioral and affective dysregulation, including hyperactivity and depression. The mechanisms are not known, but they could conceivably be due to postnatal social or environmental factors. However, we postulate that, more likely, the affective dysregulation is associated with the effects of EtOH exposure on the development of fetal serotonergic (5-HT) and/or dopaminergic (DA) pathways, i.e., pathways that in postnatal life are believed to regulate mood. Many women who use alcohol (ethanol, EtOH) during pregnancy suffer from depression and take selective serotonin reuptake inhibitors (SSRIs), which might influence these monoaminergic pathways in the fetus. Alternatively, monoaminergic pathway abnormalities might reflect a direct effect of EtOH on the fetal brain. To distinguish between these possibilities, we measured their expressions in fetal brains and in fetal brain-derived exosomes (FB-Es) isolated from the mothers' blood. We hypothesized that maternal use of EtOH and/or SSRIs during pregnancy would be associated with impaired fetal neural development, detectable as abnormal levels of monoaminergic and apoptotic biomarkers in FB-Es.

METHODS

Fetal brain tissues and maternal blood were collected at 9-23 weeks of pregnancy. EtOH groups were compared with unexposed controls matched for gestational age (GA). The expression of 84 genes associated with the DA and 5-HT pathways was analyzed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) on microarrays. FB-Es also were assayed for serotonin transporter protein (SERT) and brain-derived neurotrophic factor (BDNF) by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Six EtOH-exposed human fetal brain samples were compared to SSRI- or polydrug-exposed samples and to unexposed controls. EtOH exposure was associated with significant upregulation of DA receptor D3 and 5-HT receptor HTR2C, while HTR3A was downregulated. Monoamine oxidase A (MAOA), MAOB, the serine/threonine kinase AKT3, and caspase-3 were upregulated, while mitogen-activated protein kinase 1 (MAPK1) and AKT2 were downregulated. ETOH was associated with significant upregulation of the DA transporter gene, while SERT was downregulated. There were significant correlations between EtOH exposure and (a) caspase-3 activation, (b) reduced SERT protein levels, and (c) reduced BDNF levels. SSRI exposure independently increased caspase-3 activity and downregulated SERT and BDNF. Early exposure to EtOH and SSRI together was associated synergistically with a significant upregulation of caspase-3 and a significant downregulation of SERT and BDNF. Reduced SERT and BDNF levels were strongly correlated with a reduction in eye diameter, a somatic manifestation of FASD.

CONCLUSIONS

Maternal use of EtOH and SSRI during pregnancy each was associated with changes in fetal brain monoamine pathways, consistent with potential mechanisms for the affective dysregulation associated with FASD.

Novel Multi-Strain E3 Probiotic Formulation Improved Mental Health Symptoms and Sleep Quality in Hong Kong Chinese

Mental health issues have emerged as a significant concern in public health, given their association with physical and psychological comorbidities and the resultant socioeconomic burdens. Recent studies have highlighted the interplay between gut microbes and brain functions through the gut-brain axis. To investigate this further, we conducted a targeted 16S rRNA sequencing and comprehensive bioinformatic analysis among Southern Chinese individuals to explore the role of the gut microbiome in depression, anxiety, and sleep disturbance. We analyzed the differences in the gut microbiome profile of 68 participants with sleep disturbance and mood symptoms before and after an 8-week course of a novel oral E3 multi-strain probiotics formula. The results revealed a significant improvement in subjective sleep quality (PSQI: mean 8.79 at baseline vs. 7.10 at week 8, p < 0.001), depressive symptoms (PHQ9: mean 6.17 at baseline vs. 4.76 at week 8, p < 0.001), and anxious symptoms (GAD7: mean 4.90 at baseline vs. 3.76 at week 8, p < 0.001). Additionally, there were notable differences in beta diversity (weighted UniFrac; p = 0.045) and increased Firmicutes/Bacteroidetes (F/B) ratio (p = 4 × 10-4) were observed in the gut microbiome analysis. Furthermore, the relative abundance of Bifidobacterium bifidum (p < 0.001), Lactobacillus acidophilus (p < 0.001), Lactobacillus helveticus (p < 0.001) and Lactobacillus plantarum (p < 0.001) were significantly increased after the 8-week probiotic supplementation. Our study suggests that the gut microbial landscape varies between responders and non-responders at multiple levels, including genera, species, functional, and network interaction. Notably, the use of probiotics in populations with depressive or anxious symptoms and poor sleeping quality remodeled the gut microbiome and demonstrated improved mood and sleep quality.

Increased depression-like behaviors with altered brain dopamine metabolisms in male mice housed in large cages are alleviated by bupropion

Psycho-environmental stress-based animal models of anxiety and depression are useful for investigating pathological mechanisms and drug development. Although several rodent-based studies have reported the beneficial effects of environmental enrichment (EE) on brain plasticity and anxiety- and depression-like behaviors, other studies have reported inverse effects. Here, we found that housing male mice in EE involving large cages and other EE materials increased anxiety- and depression-like behaviors in open field and tail suspension tests (TST). We further confirmed that housing in large cages was sufficient to induce increased depression-like behaviors in the TST and reduce the saccharine preference percentage, a sign of anhedonia, in male mice. In these experiments, the number of animals per cage was equivalent to that in standard cage housing, suggesting that low density in large cages may be a determining factor for behavioral alteration. In mice housed in large cages, sex-specific dysregulation of brain monoamine systems was observed; dopamine turnover to homovanillic acid or norepinephrine in the prefrontal cortex was elevated in males, while serotonin turnover to 5-hydroxyindoleacetic acid in the amygdala was increased in females. Finally, we demonstrated that daily intraperitoneal injections of bupropion, a dopamine and norepinephrine reuptake inhibitor, counteracted large-cage housing-induced changes in depression- and anhedonia-like behaviors in male mice. Our results suggest that housing in large cages with a low density of mice is a novel paradigm to clarify the mechanisms of environmental stress-induced emotional dysregulation and to identify drugs or food factors to alleviate the dysregulation.

Stress, microRNAs, and stress-related psychiatric disorders: an overview

Stress is a major risk factor for psychiatric disorders. During and after exposure to stressors, the stress response may have pro- or maladaptive consequences, depending on several factors related to the individual response and nature of the stressor. However, the mechanisms mediating the long-term effects of exposure to stress, which may ultimately lead to the development of stress-related disorders, are still largely unknown. Epigenetic mechanisms have been shown to mediate the effects of the environment on brain gene expression and behavior. MicroRNAs, small non-coding RNAs estimated to control the expression of about 60% of all genes by post-transcriptional regulation, are a fundamental epigenetic mechanism. Many microRNAs are expressed in the brain, where they work as fine-tuners of gene expression, with a key role in the regulation of homeostatic balance, and a likely influence on pro- or maladaptive brain changes. Here we have selected a number of microRNAs, which have been strongly implicated as mediators of the effects of stress in the brain and in the development of stress-related psychiatric disorders. For all of them recent evidence is reported, obtained from rodent stress models, manipulation of microRNAs levels with related behavioral changes, and clinical studies of stress-related psychiatric disorders. Moreover, we have performed a bioinformatic analysis of the predicted brain-expressed target genes of the microRNAs discussed, and found a central role for mechanisms involved in the regulation of synaptic function. The complex regulatory role of microRNAs has suggested their use as biomarkers for diagnosis and treatment response, as well as possible therapeutic drugs. While, microRNA-based diagnostics have registered advancements, particularly in oncology and other fields, and many biotech companies have launched miRNA therapeutics in their development pipeline, the development of microRNA-based tests and drugs for brain disorders is comparatively slower.

Spirituality in Parkinson's Disease within a Sample from the USA

Spirituality and religious beliefs are important for coping with medical conditions. The dopaminergic system is involved in reward behavior, and its dysfunction in Parkinson Disease (PD) raises questions about religiosity and spirituality in people with PD. This study examines the association between levels of spirituality and religiosity and the severity of PD motor and non-motor symptoms. The secondary aim investigates the perceived impact of PD diagnosis on spirituality and religiosity. This was a cross-sectional analysis of demographic, physical, mental, and spirituality and religiosity status in patients with PD recruited for the Health Outcomes Measurement (HOME) Study at the University of Maryland Parkinson Disease and Movement Disorders Center, Baltimore, USA. Spirituality and religiosity were assessed using the Spiritual Well-being Scale, and the World Health Organization Quality of Life Spiritual Religious and Personal Belief field-test instrument. The sample size was 85 PD patients. The mean age (standard deviation) was 65.5 (9.4) years and 67.1% were male. Higher levels of spirituality and religiosity were associated with younger age, sex (female), less education, religious affiliation (Christian), and mental health status. After adjusting for age, education, gender, race, marital status, religion, physical health, mental health, and comorbidity, only anxiety was associated with all of the spirituality/religiosity assessments. The majority of patients reported no change in their religious or spiritual beliefs following diagnosis. Greater spirituality and religiosity were associated with less anxiety. Also, younger women with PD showed higher levels of spirituality and religiosity. Longitudinal studies on more diverse populations are needed.

Fluorescent-Based Neurotransmitter Sensors: Present and Future Perspectives

Neurotransmitters (NTs) are endogenous low-molecular-weight chemical compounds that transmit synaptic signals in the central nervous system. These NTs play a crucial role in facilitating signal communication, motor control, and processes related to memory and learning. Abnormalities in the levels of NTs lead to chronic mental health disorders and heart diseases. Therefore, detecting imbalances in the levels of NTs is important for diagnosing early stages of diseases associated with NTs. Sensing technologies detect NTs rapidly, specifically, and selectively, overcoming the limitations of conventional diagnostic methods. In this review, we focus on the fluorescence-based biosensors that use nanomaterials such as metal clusters, carbon dots, and quantum dots. Additionally, we review biomaterial-based, including aptamer- and enzyme-based, and genetically encoded biosensors. Furthermore, we elaborate on the fluorescence mechanisms, including fluorescence resonance energy transfer, photon-induced electron transfer, intramolecular charge transfer, and excited-state intramolecular proton transfer, in the context of their applications for the detection of NTs. We also discuss the significance of NTs in human physiological functions, address the current challenges in designing fluorescence-based biosensors for the detection of NTs, and explore their future development.

CHL1 depletion affects dopamine receptor D2-dependent modulation of mouse behavior

Introduction

The dopaminergic system plays a key role in the appropriate functioning of the central nervous system, where it is essential for emotional balance, arousal, reward, and motor control. The cell adhesion molecule close homolog of L1 (CHL1) contributes to dopaminergic system development, and CHL1 and the dopamine receptor D2 (D2R) are associated with mental disorders like schizophrenia, addiction, autism spectrum disorder and depression.

Methods

Here, we investigated how the interplay between CHL1 and D2R affects the behavior of young adult male and female wild-type (CHL+/+) and CHL1-deficient (CHL1-/-) mice, when D2R agonist quinpirole and antagonist sulpiride are applied.

Results

Low doses of quinpirole (0.02 mg/kg body weight) induced hypolocomotion of CHL1+/+ and CHL1-/- males and females, but led to a delayed response in CHL1-/- mice. Sulpiride (1 mg/kg body weight) affected locomotion of CHL1-/- females and social interaction of CHL1+/+ females as well as social interactions of CHL1-/- and CHL1+/+ males. Quinpirole increased novelty-seeking behavior of CHL1-/- males compared to CHL1+/+ males. Vehicle-treated CHL1-/- males and females showed enhanced working memory and reduced stress-related behavior.

Discussion

We propose that CHL1 regulates D2R-dependent functions in vivo. Deficiency of CHL1 leads to abnormal locomotor activity and emotionality, and to sex-dependent behavioral differences.

Synthesis of Ag nanoparticles for selective dual detection of glutathione and dopamine using N, N-dimethyl-p-phenylenediamine mediated colorimetric probe

We report a simple and easy method to synthesize Ag nanoparticles (Ag NPs) and demonstrate its potential for the detection of glutathione (GSH) and dopamine (DA) via colorimetric assay. The Ag NPs were found to be monodispersed and spherical with a size of 5 ± 2 nm. The X-ray diffraction (XRD) and high resolution transmission electron microscopy (HR-TEM) investigations revealed the formation of crystalline Ag NPs. The colour of N, N-dimethyl-p-phenylenediamine assay changed from dark pink to colourless when the concentration of GSH was increased from 1 to 40 μM. Notably, the suspension colour changed from dark pink to blue when a similar set of experiments were performed with DA. The UV/Visible and interference experiments of Ag NPs exhibited excellent sensitivity and selectivity against both GSH and DA even after the addition of 40 μM of different interference biomolecules. The calculated limit of detection (LOD) was 141 and 245 nM for GSH and DA, respectively. The real-time analysis with serum samples showed satisfactory recovery percentages of >95 and 80-90% for GSH and DA, respectively. Hence, the Ag NPs reported here have huge potential to serve as a sensitive and selective colorimetric sensor for the detection of GSH and DA for diverse applications ranging from catalysis to cancer therapy and theranostics.

Dopamine in major depressive disorder: A systematic review and meta-analysis of in vivo imaging studies

BACKGROUND

Major depressive disorder (MDD) is a leading cause of global disability. Several lines of evidence implicate the dopamine system in its pathophysiology. However, the magnitude and consistency of the findings are unknown. We address this by systematically reviewing in vivo imaging evidence for dopamine measures in MDD and meta-analysing these where there are sufficient studies.

METHODS

Studies investigating the dopaminergic system using positron emission tomography or single photon emission computed tomography in MDD and a control group were included. Demographic, clinical and imaging measures were extracted from each study, and meta-analyses and sensitivity analyses were conducted.

RESULTS

We identified 43 studies including 662 patients and 801 controls. Meta-analysis of 38 studies showed no difference in mean or mean variability of striatal D2/3 receptor availability (g = 0.06, p = 0.620), or combined dopamine synthesis and release capacity (g = 0.19, p = 0.309). Dopamine transporter (DAT) availability was lower in the MDD group in studies using DAT selective tracers (g = -0.56, p = 0.006), but not when tracers with an affinity for serotonin transporters were included (g = -0.21, p = 0.420). Subgroup analysis showed greater dopamine release (g = 0.49, p = 0.030), but no difference in dopamine synthesis capacity (g = -0.21, p = 0.434) in the MDD group. Striatal D1 receptor availability was lower in patients with MDD in two studies.

CONCLUSIONS

The meta-analysis indicates striatal DAT availability is lower, but D2/3 receptor availability is not altered in people with MDD compared to healthy controls. There may be greater dopamine release and lower striatal D1 receptors in MDD, although further studies are warranted. We discuss factors associated with these findings, discrepancies with preclinical literature and implications for future research.

Neural energy computations based on Hodgkin-Huxley models bridge abnormal neuronal activities and energy consumption patterns of major depressive disorder

Limited by the current experimental techniques and neurodynamical models, the dysregulation mechanisms of decision-making related neural circuits in major depressive disorder (MDD) are still not clear. In this paper, we proposed a neural coding methodology using energy to further investigate it, which has been proven to strongly complement the neurodynamical methodology. We augmented the previous neural energy calculation method, and applied it to our VTA-NAc-mPFC neurodynamical H-H models. We particularly focused on the peak power and energy consumption of abnormal ion channel (ionic) currents under different concentrations of dopamine input, and investigated the abnormal energy consumption patterns for the MDD group. The results revealed that the energy consumption of medium spiny neurons (MSNs) in the NAc region were lower in the MDD group than that of the normal control group despite having the same firing frequencies, peak action potentials, and average membrane potentials in both groups. Dopamine concentration was also positively correlated with the energy consumption of the pyramidal neurons, but the patterns of different interneuron types were distinct. Additionally, the ratio of mPFC's energy consumption to total energy consumption of the whole network in MDD group was lower than that in normal control group, revealing that the mPFC region in MDD group encoded less neural information, which matched the energy consumption patterns of BOLD-fMRI results. It was also in line with the behavioral characteristics that MDD patients demonstrated in the form of reward insensitivity during decision-making tasks. In conclusion, the model in this paper was the first neural network energy computational model for MDD, which showed success in explaining its dynamical mechanisms with an energy consumption perspective. To build on this, we demonstrated that energy consumption levels can be used as a potential indicator for MDD, which also showed a promising pipeline to use an energy methodology for studying other neuropsychiatric disorders.

The Effect of Transcranial Direct Current Stimulation (tDCS) on Anorexia Nervosa: A Narrative Review

(1) Introduction: Anorexia nervosa (AN) is a severe, debilitating disease with high incidence and high mortality. The methods of treatment used so far are moderately effective. Evidence from neuroimaging studies helps to design modern methods of therapy. One of them is transcranial direct current stimulation (tDCS), a non-invasive brain neuromodulation technique. (2) Methods: The purpose of this narrative review is to bring together all studies investigating the use of tDCS in the treatment of AN and to evaluate its effect and efficiency. Searches were conducted in the Pubmed/Medline, Research Gate, and Cochrane databases. (3) Results: The literature search resulted in five articles. These studies provide preliminary evidence that tDCS has the potential to alter eating behaviour, body weight, and food intake. Additionally, tDCS reduced symptoms of depression. Throughout all trials, stimulation targeted the left dorsolateral prefrontal cortex (DLPFC). Although the number of studies included is limited, attempts were made to elucidate the potential mechanisms underlying tDCS action in individuals with AN. Recommendations for future tDCS research in AN were issued. (4) Conclusions: The included studies have shown that tDCS stimulation of the left DLPFC has a positive effect on AN clinical symptoms and may improve them, as measured by various assessment measures. It is important to conduct more in-depth research on the potential benefits of using tDCS for treating AN. This should entail well-designed studies incorporating advanced neuroimaging techniques, such as fMRI. The aim is to gain a better understanding of how tDCS works in AN.