The circadian phase of antenatal glucocorticoid treatment affects the risk of behavioral disorders

Profiling metabolome of mouse embryonic cerebrospinal fluid following maternal immune activation

The embryonic cerebrospinal fluid (eCSF) plays an essential role in the development of the central nervous system (CNS), influencing processes from neurogenesis to lifelong cognitive functions. An important process affecting eCSF composition is inflammation. Inflammation during development can be studied using the maternal immune activation (MIA) mouse model, which displays altered cytokine eCSF composition and mimics neurodevelopmental disorders including autism spectrum disorder (ASD). The limited nature of eCSF as a biosample restricts its research and has hindered our understanding of the eCSF's role in brain pathologies. Specifically, investigation of the small molecule composition of the eCSF is lacking, leaving this aspect of the eCSF composition under-studied. We report here the eCSF metabolome as a resource for investigating developmental neuropathologies from a metabolic perspective. Our reference metabolome includes comprehensive MS1 and MS2 datasets and evaluates two mouse strains (CD-1 and C57Bl/6) and two developmental time points (E12.5 and E14.5). We illustrate the reference metabolome's utility by using untargeted metabolomics to identify eCSF-specific compositional changes following MIA. We uncover MIA-relevant metabolic pathways as differentially abundant in eCSF and validate changes in glucocorticoid and kynurenine pathways through targeted metabolomics approaches. Our resource will guide future studies into the causes of MIA neuropathology and the impact of eCSF composition on brain development.

Dissecting the networks underlying diverse brain disorders after prenatal glucocorticoid overexposure

New human life begins in the uterus in a period of both extreme plasticity and sensitivity to environmental disturbances. The fetal stage is also a vital period for central nervous system development, with experiences at this point profoundly and permanently shaping brain structure and function. As such, some brain disorders may originate in utero. Glucocorticoids, a class of essential stress hormones, play indispensable roles in fetal development, but overexposure may have lasting impacts on the brain. In this review, we summarize data from recent clinical and non-clinical studies regarding alterations in fetal brains due to prenatal glucocorticoid overexposure that are associated with nervous system disorders. We discuss relevant changes to brain structure and cellular functions and explore the underlying molecular mechanisms. In addition, we summarize factors that may cause differential outcomes between varying brain regions, and outline clinically feasible intervention strategies that are expected to minimize negative consequences arising from fetal glucocorticoid overexposure. Finally, we highlight the need for experimental evidence aided by new technologies to clearly determine the effects of excessive prenatal glucocorticoid exposure. This review consolidates diverse findings to help researchers better understand the relationship between the prenatal glucocorticoid overexposure and the effects it has on various fetal brain regions, promoting further development of critical intervention strategies.

Neuropsychiatric Adverse Effects of Synthetic Glucocorticoids: A Systematic Review and Meta-Analysis

CONTEXT

Synthetic glucocorticoids are widely used to treat patients with a broad range of diseases. While efficacious, glucocorticoids can be accompanied by neuropsychiatric adverse effects.

OBJECTIVE

This systematic review and meta-analysis assesses and quantifies the proportion of different neuropsychiatric adverse effects in patients using synthetic glucocorticoids.

METHODS

Six electronic databases were searched to identify potentially relevant studies. Randomized controlled trials, cohort studies, and cross-sectional studies assessing psychiatric side effects of glucocorticoids measured with validated questionnaires were eligible. Risk of bias was assessed with RoB 2, ROBINS-I, and AXIS appraisal tool. For proportions of neuropsychiatric outcomes, we pooled proportions, and when possible, differences in questionnaire scores between glucocorticoid users and nonusers were expressed as standardized mean differences (SMD). Data were pooled in a random-effects logistic regression model.

RESULTS

We included 49 studies with heterogeneity in study populations, type, dose, and duration of glucocorticoids. For glucocorticoid users, meta-analysis showed a proportion of 22% for depression (95% CI, 14%-33%), 11% for mania (2%-46%), 8% for anxiety (2%-25%), 16% for delirium (6%-36%), and 52% for behavioral changes (42%-61%). Questionnaire scores for depression (SMD of 0.80 [95% CI 0.35-1.26]), and mania (0.78 [0.14-1.42]) were higher than in controls, indicating more depressive and manic symptoms following glucocorticoid use.

CONCLUSION

The heterogeneity of glucocorticoid use is reflected in the available studies. Despite this heterogeneity, the proportion of neuropsychiatric adverse effects in glucocorticoid users is high. The most substantial associations with glucocorticoid use were found for depression and mania. Upon starting glucocorticoid treatment, awareness of possible psychiatric side effects is essential. More structured studies on incidence and potential pathways of neuropsychiatric side effects of prescribed glucocorticoids are clearly needed.

Ontogeny of the circadian system: a multiscale process throughout development

The 24 h (circadian) timing system develops in mammals during the perinatal period. It carries out the essential task of anticipating daily recurring environmental changes to identify the best time of day for each molecular, cellular, and systemic process. Although significant knowledge has been acquired about the organization and function of the adult circadian system, relatively little is known about its ontogeny. During the perinatal period, the circadian system progressively gains functionality under the influence of the early environment. This review explores current evidence on the development of the circadian clock in mammals, highlighting the multilevel complexity of the process and the importance of gaining a better understanding of its underlying biology.

Fighting Against the Clock: Circadian Disruption and Parkinson's Disease

Circadian disruption is being increasingly recognized as a critical factor in the development and progression of Parkinson's disease (PD). This review aims to provide an in-depth overview of the relationship between circadian disruption and PD by exploring the molecular, cellular, and behavioral aspects of this interaction. This review will include a comprehensive understanding of how the clock gene system and transcription-translation feedback loops function and how they are diminished in PD. The article also discusses the role of clock genes in the regulation of circadian rhythms, as well as the impact of clock gene dysregulation on mitochondrial function, oxidative stress, and neuroinflammation, including the microbiota-gut-brain axis, which have all been proposed as being crucial mechanisms in the pathophysiology of PD. Finally, this review highlights potential therapeutic strategies targeting the clock gene system and circadian rhythm for the treatment of PD.

Metabolomics of Mouse Embryonic CSF Following Maternal Immune Activation

The cerebrospinal fluid (CSF) serves various roles in the developing central nervous system (CNS), from neurogenesis to lifelong cognitive functions. Changes in CSF composition due to inflammation can impact brain function. We recently identified an abnormal cytokine signature in embryonic CSF (eCSF) following maternal immune activation (MIA), a mouse model of autism spectrum disorder (ASD). We hypothesized that MIA leads to other alterations in eCSF composition and employed untargeted metabolomics to profile changes in the eCSF metabolome in mice after inducing MIA with polyI:C. We report these data here as a resource, include a comprehensive MS1 and MS2 reference dataset, and present additional datasets comparing two mouse strains (CD-1 and C57Bl/6) and two developmental time points (E12.5 and E14.5). Targeted metabolomics further validated changes upon MIA. We show a significant elevation of glucocorticoids and kynurenine pathway related metabolites. Both pathways are relevant for suppressing inflammation or could be informative as disease biomarkers. Our resource should inform future mechanistic studies regarding the etiology of MIA neuropathology and roles and contributions of eCSF metabolites to brain development.

Temporal associations between salivary cortisol and emotions in clinically depressed individuals and matched controls: A dynamic time warp analysis

Depression can be understood as a complex dynamic system where depressive symptoms interact with one another. Cortisol is suggested to play a major role in the pathophysiology of depression, but knowledge on the temporal interplay between cortisol and depressive symptoms is scarce. We aimed to analyze the temporal connectivity between salivary cortisol and momentary affective states in depressed individuals and controls. Thirty pair-matched depressed and non-depressed participants completed questionnaires on momentary positive (PA) and negative (NA) affect and collected saliva three times a day for 30 days. The association between cortisol and affect was analyzed by dynamic time warp (DTW) analyses. These analyses involved lag-1 backward to lag-1 forward undirected analyses and lag-0 and lag-1 forward directed analyses. Large inter- and intra-individual variability in the networks were found. At the group level, with undirected analysis PA and NA were connected in the networks in depressed individuals and in controls. Directed analyses indicated that increases in cortisol preceded specific NA items in controls, but tended to follow upon specific affect items increase in depressed individuals. To conclude, at group level, changes in cortisol levels in individuals diagnosed with a depression may be a result of changes in affect, rather than a cause.

Modulating glucocorticoid receptor actions in physiology and pathology: Insights from coregulators

Glucocorticoids (GCs) are a class of steroid hormones that regulate key physiological processes such as metabolism, immune function, and stress responses. The effects of GCs are mediated by the glucocorticoid receptor (GR), a ligand-dependent transcription factor that activates or represses the expression of hundreds to thousands of genes in a tissue- and physiological state-specific manner. The activity of GR is modulated by numerous coregulator proteins that interact with GR in response to different stimuli assembling into a multitude of DNA-protein complexes and facilitate the integration of these signals, helping GR to communicate with basal transcriptional machinery and chromatin. Here, we provide a brief overview of the physiological and molecular functions of GR, and discuss the roles of GR coregulators in the immune system, key metabolic tissues and the central nervous system. We also present an analysis of the GR interactome in different cells and tissues, which suggests tissue-specific utilization of GR coregulators, despite widespread functions shared by some of them.

Antenatal corticosteroids and outcomes of small for gestational age infants born at 24-31 gestational weeks: a population-based propensity score matching analysis

PURPOSE

To evaluate the effect of antenatal corticosteroid (ACS) treatment on neonatal outcomes in small for gestational age (SGA) infants born at 24-31 gestational weeks compared with non-SGA infants.

METHODS

A population-based retrospective study was conducted that analyzed clinical data from the Neonatal Research Network of Japan database, which enrolls neonates born at < 32 gestational weeks and weighing 1500 g or less (n = 22,414). Propensity score matching (with the ratio of ACS to no-ACS groups of 1:1) was performed in SGA (n = 7028) and non-SGA (n = 15,386) infants, respectively. Univariate logistic and interaction analyses were performed to compare the short-term neonatal outcomes of infants with and without ACS treatment in utero.

RESULTS

In the SGA and non-SGA infants, ACS treatment significantly reduced in-hospital mortality (odds ratio 0.67 95% confidence interval [0.50-0.88] and 0.62 [0.50-0.78], respectively), respiratory distress syndrome (0.77 [0.69-0.87] and 0.63 [0.58-0.68], respectively), and composite adverse outcomes (0.73 [0.58-0.91] and 0.57 [0.50-0.65], respectively). ACS treatment also significantly reduced intraventricular hemorrhage (grade III/IV), periventricular leukomalacia, and sepsis in the non-SGA infants, but not in the SGA infants. However, interaction analyses revealed no significant differences between the SGA and non-SGA infants in the efficacy of ACS treatment on short-term outcomes except for respiratory distress syndrome.

CONCLUSIONS

ACS treatment was associated with beneficial effects on mortality, respiratory distress syndrome, and adverse composite outcomes in extremely and very preterm SGA infants, with similar efficacy on all neonatal outcomes except for respiratory distress syndrome observed in the non-SGA infants.

The importance of the circadian trough in glucocorticoid signaling: a variation on B-flat

Glucocorticoid hormones are essential for health, but overexposure may lead to many detrimental effects, including metabolic, psychiatric, and bone disease. These effects may not only be due to increased overall exposure to glucocorticoids, but also to elevated hormone levels at the time of the physiological circadian trough of glucocorticoid levels. The late Mary Dallman developed a model that allows the differentiation between the effects of overall 24-hour glucocorticoid overexposure and the effects of a lack of circadian rhythmicity. For this, she continuously treated rats with a low dose of corticosterone (or "B"), which leads to a constant hormone level, without 24-hour overexposure using subcutaneously implanted pellets. The data from this "B-flat" model suggest that even modest elevations of glucocorticoid signaling during the time of the normal circadian trough of hormone secretion are a substantial contributor to the negative effects of glucocorticoids on health.

Circadian glucocorticoids throughout development

Glucocorticoids (GCs) are essential drivers of mammalian tissue growth and maturation during one of the most critical developmental windows, the perinatal period. The developing circadian clock is shaped by maternal GCs. GC deficits, excess, or exposure at the wrong time of day leads to persisting effects later in life. During adulthood, GCs are one of the main hormonal outputs of the circadian system, peaking at the beginning of the active phase (i.e., the morning in humans and the evening in nocturnal rodents) and contributing to the coordination of complex functions such as energy metabolism and behavior, across the day. Our article discusses the current knowledge on the development of the circadian system with a focus on the role of GC rhythm. We explore the bidirectional interaction between GCs and clocks at the molecular and systemic levels, discuss the evidence of GC influence on the master clock in the suprachiasmatic nuclei (SCN) of the hypothalamus during development and in the adult system.

Circle(s) of Life: The Circadian Clock from Birth to Death

Most lifeforms on earth use endogenous, so-called circadian clocks to adapt to 24-h cycles in environmental demands driven by the planet’s rotation around its axis. Interactions with the environment change over the course of a lifetime, and so does regulation of the circadian clock system. In this review, we summarize how circadian clocks develop in humans and experimental rodents during embryonic development, how they mature after birth and what changes occur during puberty, adolescence and with increasing age. Special emphasis is laid on the circadian regulation of reproductive systems as major organizers of life segments and life span. We discuss differences in sexes and outline potential areas for future research. Finally, potential options for medical applications of lifespan chronobiology are discussed.

Pu-erh Tea Restored Circadian Rhythm Disruption by Regulating Tryptophan Metabolism

Pu-erh tea is a healthy beverage rich in phytochemicals, and its effect on the risk of inducing circadian rhythm disorders (CRD) is unclear. In this study, healthy mice were given water or 0.25% (w/v) Pu-erh tea for 7 weeks, followed by a 40 day disruption of the light/dark cycle. CRD caused dysregulation of neurotransmitter secretion and clock gene oscillations, intestinal inflammation, and disruption of intestinal microbes and metabolites. Pu-erh tea boosted the indole and 5-hydroxytryptamine pathways of tryptophan metabolism via the gut-liver-brain axis. Furthermore, its metabolites (e.g., IAA, Indole, 5-HT) enhanced hepatic glycolipid metabolism and down-regulated intestinal oxidative stress by improving the brain hormone release. Tryptophan metabolites and bile acids also promoted liver lipid metabolism and inhibited intestinal inflammation (MyD88/NF-κB) via the enterohepatic circulation. Collectively, 0.25% (w/v) Pu-erh tea has the potential to prevent CRD by promoting indole and 5-HT pathways of tryptophan metabolism and signaling interactions in the gut-liver-brain axis.

Effect of rapid eye movement sleep deprivation during pregnancy on glucocorticoid receptor regulation of HPA axis function in female offspring

Poor maternal sleep quality during the different phases of pregnancy acts as a prenatal stress and is critical for fetal development. Despite the potential adverse effects of maternal stress on the behavior and physiology of the offspring, the mechanisms remain poorly understood. The present study investigates the effects of maternal sleep deprivation (SD) at different stages of pregnancy on the hypothalamic-pituitary-adrenal (HPA) axis in female offspring. The pregnant rats were subjected to sleep deprivation of 12 h per day at different stages; early (ESD), mid (MSD), and late (LSD) stages, on pregnancy days 1-7, 8-14, and 14-20, respectively. At postnatal day 60, levels of corticosterone (CORT), hypothalamic corticotropin-releasing factor receptor 1 (CRF-R1), and hippocampal glucocorticoid receptors (GR) were evaluated in the offspring. Although the hypothalamic CRF-R1 level was increased in the offspring of SD dams, immunohistochemical staining showed reduced immunoreactivity of GR in ESD and LSD offspring hippocampal area. Altogether, the data suggests that a critical period for adverse effects of SD on the HPA axis in female offspring of Wistar rats may be during early and late pregnancy.

Tea combats circadian rhythm disorder syndrome via the gut-liver-brain axis: potential mechanisms speculated

Circadian rhythm is an intrinsic mechanism developed by organisms to adapt to external environmental signals. Nowadays, owing to the job and after-work entertainment, staying up late - Circadian rhythm disorders (CRD) are common. CRD is linked to the development of fatty liver, type 2 diabetes, and chronic gastroenteritis, which affecting the body's metabolic and inflammatory responses via multi-organ crosstalk (gut-liver-brain axis, etc.). However, studies on the mechanisms of multi-organ interactions by CRD are still weak. Current studies on therapeutic agents for CRD remain inadequate, and phytochemicals have been shown to alleviate CRD-induced syndromes that may be used for CRD-therapy in the future. Tea, a popular phytochemical-rich beverage, reduces glucolipid metabolism and inflammation. But it is immature and unclear in the mechanisms of alleviation of CRD-mediated syndrome. Here, we have analyzed the threat of CRD to hosts and their offspring' health from the perspective of the "gut-liver-brain" axis. The potential mechanisms of tea in alleviating CRD were further explored. It might be by interfering with bile acid metabolism, tryptophan metabolism, and G protein-coupled receptors, with FXR, AHR, and GPCR as potential targets. We hope to provide new perspectives on the role of tea in the prevention and mitigation of CRD.HighlightsThe review highlights the health challenges of CRD via the gut-liver-brain axis.CRD research should focus on the health effects on healthy models and its offspring.Tea may prevent CRD by regulating bile acid, tryptophan, and GPCR.Potential targets for tea prevention and mitigation of CRD include FXR, AHR and GPCR.A comprehensive assessment mechanism for tea in improving CRD should be established.

Administration of Antenatal Corticosteroids: Current State of Knowledge

The administration of a single course of corticosteroids before week 34 + 0 of gestation in cases with impending preterm birth is now standard procedure in obstetric care and firmly established in the guidelines of different countries. But despite the apparently convincing data, numerous aspects of this intervention have not yet been properly studied. It is still not clear which corticosteroid achieves the best results. There are very few studies on what constitutes an appropriate dose, circadian rhythms, the time frame in which corticosteroids are effective, and the balance between the risks and benefits of repeat administration. As the existing studies have rarely included patients before week 24 + 0 of gestation, we have very little information on the possible benefits of administering corticosteroids before this timepoint. If corticosteroids are administered antenatally after week 34 + 0 of gestation, the short-term benefit may be offset by the long-term adverse effect on psychomotor development. This present study summarizes the current state of knowledge regarding these issues.

A Timely Administration of Antenatal Steroids Is Highly Protective Against Intraventricular Hemorrhage: An Observational Multicenter Cohort Study of Very Low Birth Weight Infants

AIM

The aim of the study is to evaluate the influence of the timing of antenatal steroids (ANSs) on neonatal outcome of very low birth weight infants (VLBWI) born before 30 weeks of gestation in the German Neonatal Network.

METHODS

The German Neonatal Network is a large population-based cohort study enrolling VLBWIs since 2009. We included 672 neonates, who were born between January 1, 2009 and December 31, 2019 in our analysis in 10 selected centers. Infants were divided into four subgroups based on the interval between the first steroid administration and preterm birth: (I) two doses of betamethasone, ANS-birth interval: >24 h to 7 days, n = 187, (II) only one dose of betamethasone, ANS-birth interval 0-24 h, n = 70, (III) two doses of betamethasone, ANS-birth interval >7 days, n = 177, and (IV) no antenatal steroids, n = 238. Descriptive statistics and logistic regression analyses were performed for the main neonatal outcome parameters. Group IV (no ANS) was used as a reference.

RESULTS

An ANS-birth interval of 24 h to 7 days after the first dose was associated with a reduced risk for intraventricular hemorrhage (OR 0.17; 95% CI 0.09-0.31, p < 0.001) and mechanical ventilation (OR 0.37; 95% CI 0.23-0.61, p < 0.001), whereas the group of infants that only received a single dose of steroids reflected a subgroup at high risk for adverse neonatal outcomes; an ANS-birth interval of >7 days was still associated with a lower risk for intraventricular hemorrhage (OR 0.43; 95% CI 0.25-0.72, p = 0.002) and the need for mechanical ventilation (OR 0.43; 95% CI 0.27-0.71, p = 0.001).

CONCLUSION

Our observational data indicate that an ANS-birth interval of 24 h to 7 days is strongly associated with a reduced risk of intraventricular hemorrhage in VLBWIs. Further research is needed to improve the prediction of preterm birth in order to achieve a timely administration of antenatal steroids that may improve neonatal outcomes such as intraventricular hemorrhage.

Astrocytes as essential time-keepers of the central pacemaker

Since the early observations made by Santiago Ramon y Cajal more than a century ago till now, astrocytes have gradually gained protagonism as essential partners of neurons in building brain circuits that regulate complex behavior. In mammals, processes such as sleep-wake cycle, locomotor activity, cognition and memory consolidation, homeostatic and hedonic appetite and stress response (among others), are synchronized in 24-h rhythms by the circadian system. In such a way, physiology efficiently anticipates and adapts to daily recurring changes in the environment. The hypothalamic suprachiasmatic nucleus (SCN) is considered the central pacemaker, it has been traditionally described as a nucleus of around 10,000 neurons nearly all GABAergic able to be entrained by light and to convey time information through multiple neuronal and hormonal pathways. Only recently, this neuro-centered view was challenged by breakthrough discoveries implicating astrocytes as essential time-keepers. In the present review, we will describe the current view on the SCN circuit and discuss whether astrocytic functions described in other brain regions and state-of-the-art experimental approaches, could help explaining better those well- and not so well-known features of the central pacemaker.

Eat, sleep, repeat - endocrine regulation of behavioural circadian rhythms

The adaptation of organisms to a rhythmic environment is mediated by an internal timing system termed the circadian clock. In mammals, molecular clocks are found in all tissues and organs. This circadian clock network regulates the release of many hormones, which in turn influence some of the most vital behavioural functions. Sleep-wake cycles are under strict circadian control with strong influence of rhythmic hormones such as melatonin, cortisol and others. Food intake, in contrast, receives circadian modulation through hormones such as leptin, ghrelin, insulin and orexin. A third behavioural output covered in this review is mating and bonding behaviours, regulated through circadian rhythms in steroid hormones and oxytocin. Together, these data emphasize the pervasive influence of the circadian clock system on behavioural outputs and its mediation through endocrine networks.

The trophoblast clock controls transport across placenta in mice

In mammals, 24-h rhythms of physiology and behavior are organized by a body-wide network of clock genes and proteins. Despite the well-known function of the adult circadian system, the roles of maternal, fetal and placental clocks during pregnancy are poorly defined. In the mature mouse placenta, the labyrinth zone (LZ) is of fetal origin and key for selective nutrient and waste exchange. Recently, clock gene expression has been detected in LZ and other fetal tissues; however, there is no evidence of a placental function controlled by the LZ clock. Here, we demonstrate that specifically the trophoblast layer of the LZ harbors an already functional clock by late gestation, able to regulate in a circadian manner the expression and activity of the xenobiotic efflux pump, ATP-binding cassette sub-family B member 1 (ABCB1), likely gating the fetal exposure to drugs from the maternal circulation to certain times of the day. As more than 300 endogenous and exogenous compounds are substrates of ABCB1, our results might have implications in choosing the maternal treatment time when aiming either maximal/minimal drug availability to the fetus/mother.

Feto-Maternal Crosstalk in the Development of the Circadian Clock System

The circadian (24 h) clock system adapts physiology and behavior to daily recurring changes in the environment. Compared to the extensive knowledge assembled over the last decades on the circadian system in adults, its regulation and function during development is still largely obscure. It has been shown that environmental factors, such as stress or alterations in photoperiod, disrupt maternal neuroendocrine homeostasis and program the offspring’s circadian function. However, the process of circadian differentiation cannot be fully dependent on maternal rhythms alone, since circadian rhythms in offspring from mothers lacking a functional clock (due to SCN lesioning or genetic clock deletion) develop normally. This mini-review focuses on recent findings suggesting that the embryo/fetal molecular clock machinery is present and functional in several tissues early during gestation. It is entrained by maternal rhythmic signals crossing the placenta while itself controlling responsiveness to such external factors to certain times of the day. The elucidation of the molecular mechanisms through which maternal, placental and embryo/fetal clocks interact with each other, sense, integrate and coordinate signals from the early life environment is improving our understanding of how the circadian system emerges during development and how it affects physiological resilience against external perturbations during this critical time period.

Breastfeeding for 3 Months or Longer but Not Probiotics Is Associated with Reduced Risk for Inattention/Hyperactivity and Conduct Problems in Very-Low-Birth-Weight Children at Early Primary School Age

(1) Background: We aimed to evaluate the effect of proposed “microbiome-stabilising interventions”, i.e., breastfeeding for ≥3 months and prophylactic use of Lactobacillus acidophilus/ Bifidobacterium infantis probiotics on neurocognitive and behavioral outcomes of very-low-birthweight (VLBW) children aged 5–6 years. (2) Methods: We performed a 5-year-follow-up assessment including a strength and difficulties questionnaire (SDQ) and an intelligence quotient (IQ) assessment using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI)-III test in preterm children previously enrolled in the German Neonatal Network (GNN). The analysis was restricted to children exposed to antenatal corticosteroids and postnatal antibiotics. (3) Results: 2467 primary school-aged children fulfilled the inclusion criteria. In multivariable linear regression models breastfeeding ≥3 months was associated with lower conduct disorders (B (95% confidence intervals (CI)): −0.25 (−0.47 to −0.03)) and inattention/hyperactivity (−0.46 (−0.81 to −0.10)) as measured by SDQ. Probiotic treatment during the neonatal period had no effect on SDQ scores or intelligence. (4) Conclusions: Prolonged breastfeeding of highly vulnerable infants may promote their mental health later in childhood, particularly by reducing risk for inattention/hyperactivity and conduct disorders. Future studies need to disentangle the underlying mechanisms during a critical time frame of development.