Association between common early-childhood infection and subsequent depressive symptoms and psychotic experiences in adolescence: a population-based longitudinal birth cohort study

Neonatal immune challenge poses a sex-specific risk for epigenetic microglial reprogramming and behavioral impairment

While the precise processes underlying a sex bias in the development of central nervous system (CNS) disorders are unknown, there is growing evidence that an early life immune activation can contribute to the disease pathogenesis. When we mimicked an early systemic viral infection or applied murine cytomegalovirus (MCMV) systemically in neonatal female and male mice, only male adolescent mice presented behavioral deficits, including reduced social behavior and cognition. This was paralleled by an increased amount of infiltrating T cells in the brain parenchyma, enhanced interferon-γ (IFNγ) signaling, and epigenetic reprogramming of microglial cells. These microglial cells showed increased phagocytic activity, which resulted in abnormal loss of excitatory synapses within the hippocampal brain region. None of these alterations were seen in female adolescent mice. Our findings underscore the early postnatal period's susceptibility to cause sex-dependent long-term CNS deficiencies following infections.

Once induced, it lasts for a long time: the structural and molecular signatures associated with depressive-like behavior after neonatal immune activation

Adverse factors such as stress or inflammation in the neonatal period can affect the development of certain brain structures and have negative delayed effects throughout the lifespan of an individual, by reducing cognitive abilities and increasing the risk of psychopathologies. One possible reason for these delayed effects is the neuroinflammation caused by neonatal immune activation (NIA). Neuroinflammation can lead to disturbances of neurotransmission and to reprogramming of astroglial and microglial brain cells; when combined, the two problems can cause changes in the cytoarchitecture of individual regions of the brain. In addition, neuroinflammation may affect the hypothalamic-pituitary-adrenal (HPA) axis and processes of oxidative stress, thereby resulting in higher stress reactivity. In our review, we tried to answer the questions of whether depressive-like behavior develops after NIA in rodents and what the molecular mechanisms associated with these disorders are. Most studies indicate that NIA does not induce depressive-like behavior in a steady state. Nonetheless, adult males (but not females or adolescents of both sexes) with experience of NIA exhibit marked depressive-like behavior when exposed to aversive conditions. Analyses of molecular changes have shown that NIA leads to an increase in the amount of activated microglia and astroglia in the frontal cortex and hippocampus, an increase in oxidative-stress parameters, a change in stress reactivity of the HPA axis, and an imbalance of cytokines in various regions of the brain, but not in blood plasma, thus confirming the local nature of the inflammation. Therefore, NIA causes depressive-like behavior in adult males under aversive testing conditions, which are accompanied by local inflammation and have sex- and age-specific effects.

Back to the Future: The Role of Infections in Psychopathology. Focus on OCD

OBJECTIVE

Recently, there has been a resurgence of interest in the relationship between infections and psychopathology, given the increasing data on the neurotropism and neurological/psychiatric morbidity of the SARS-COV2 virus, responsible for the current worldwide pandemic. Although the majority of observations were those obtained in mood and schizophrenic disorders, a few data are also available on the presence of bacterial or viral infections in patients suffering from obsessive-compulsive disorder (OCD). Therefore, given the limited information, the present paper aimed at reviewing the most updated evidence of infections in neuropsychiatric disorders and their possible mechanisms of actions, with a narrow focus on microbes in OCD.

METHOD

This paper is a narrative review. The databases of PubMed, Scopus, Embase, PsycINFO and Google Scholar were accessed to research and collect English language papers published between 1 January 1980 and 31 December 2021. The data on PANDAS/PANS and those observed during severe brain infections were excluded.

RESULTS

Several pathogens have been associated with an increased risk to develop a broad spectrum of neuropsychiatric conditions, such as schizophrenia, mood disorders, autism, attention-deficit/hyperactivity disorder, anorexia nervosa, and post-traumatic stress disorder. Some evidence supported a possible role of infections also in the pathophysiology of OCD. Infections from Herpes simplex virus 1, Borna disease virus, Group A-Beta Hemolytic Streptococcus, Borrelia spp., and Toxoplasma gondii were actually found in patients with OCD. Although different mechanisms have been hypothesized, all would converge to trigger functional/structural alterations of specific circuits or immune processes, with cascade dysfunctions of several other systems.

CONCLUSIONS

Based on the current evidence, a possible contribution of different types of microbes has been proposed for different neuropsychiatric disorders including OCD. However, the currently available literature is meager and heterogeneous in terms of sample characteristics and methods used. Therefore, further studies are needed to better understand the impact of infectious agents in neuropsychiatric disorders. Our opinion is that deeper insights in this field might contribute to a better definition of biological underpinnings of specific clinical pictures, as well as to promote psychiatric precision medicine, with treatments based on altered pathological pathways of single patients. This might be particularly relevant in OCD, a disorder with a high proportion of patients who are resistant or do not respond to conventional therapeutic strategies.

COVID-19 Infection and Psychotic Experiences: Findings From the Healthy Minds Study 2020

Background

Clinical reports from across the world have documented psychosis in the context of COVID-19 infection; however, there has yet to be a large-scale epidemiological study to confirm this association.

Methods

We analyzed data from the Healthy Minds Study (N = 15,935; conducted between September and December 2020), which was administered online to students attending one of 28 colleges in the United States. Using multivariable logistic regression, we examined the associations between COVID-19 infection/severity and psychotic experiences over the past 12 months, adjusting for age, gender, race/ethnicity, and international student status as well as anxiety and depression.

Results

More than one fifth of the analytic sample reported COVID-19 infection, and about one in six students with COVID-19 infection reported psychotic experiences over the past 12 months. In weighted multivariable logistic regression models, COVID-19 infection was associated with significantly greater odds of having psychotic experiences (adjusted odds ratio 1.36, 95% CI 1.19–1.48). Compared with being asymptomatic, having moderate (adjusted odds ratio 1.85, 95% CI 1.03–3.31) or severe (adjusted odds ratio 1.76, 95% CI 1.11–2.77) symptoms was associated with significantly greater odds of having psychotic experiences. These associations became statistically nonsignificant when adjusting for depression and anxiety. Hospitalization was not significantly associated with psychotic experiences among students with COVID-19 infection.

Conclusions

Psychotic experiences are associated with COVID-19 infections, though much of the association is attenuated when accounting for anxiety and depression. Findings based on this sample of college students should be replicated outside of the college context to determine whether psychosis is a neuropsychiatric symptom during and after COVID-19 infection.

Association Between Childhood Visual Acuity and Late Adolescent Psychotic Experiences: A Prospective Birth Cohort Study

A cross-sectional association between visual impairment and psychosis exists, but longitudinal evidence from children and young people is limited. We investigated whether childhood visual acuity was associated with subsequent psychotic experiences. Our sample was 6686 individuals from the Avon Longitudinal Study of Parents and Children (ALSPAC). We investigated whether our primary exposures, best corrected visual acuity at ages 7 and 11, were associated with psychotic experiences at ages 17 and 24. We also tested whether the following exposures at ages 7 and 11 were associated with subsequent psychotic experiences: requiring glasses, presence of any visual impairment, and between-eye visual acuity difference; and at age 7: strabismus, measures of binocular vision, history of eye patch, near vision impairment, and abnormal saccadic or pursuit eye movements. Analyses used multilevel models before and after adjusting for confounders. Odds of psychotic experiences increased with each 0.1-point deterioration in visual acuity score at age 11 (adjusted odds ratio [AOR] 1.23; 95% confidence interval [CI] 1.06-1.42), and at age 7 (AOR 1.18; 95% CI 1.00-1.40). Wearing glasses and visual impairment at age 11 were associated with psychotic experiences (AOR 1.63; 95% CI 1.21-2.19; AOR 1.64; 95% CI 1.23-2.19, respectively). There was no evidence of an association with other visual exposures. Visual acuity impairment in childhood is associated with psychotic experiences in late adolescence. Future research should aim to elucidate the nature of this association.

Direction of association between Cardiovascular risk and depressive symptoms during the first 18 years of life: A prospective birth cohort study

BACKGROUND

Cardiovascular disease (CVD) and depression are bidirectionally associated in adults. However, the direction of association between CVD risk and depressive symptoms in young people and potential mechanisms are poorly understood.

METHODS

Using longitudinal birth cohort data, we created a CVD risk score age at 15 using age, ethnicity, physical activity, maternal social status, maternal smoking, own smoking, BMI, systolic blood pressure, LDL, HDL and triglycerides. We used regression analysis to test: (1) association between CVD risk score at age 15 and depressive symptoms at ages 12 and 18; (2) association of IL-6 and CRP at age 9 with depressive symptoms at age 12 and CVD risk score at age 15; and (3) mediating effects of CVD risk score on associations of IL-6/CRP at age 9 with depressive symptoms at age 18.

RESULTS

The risk set comprised 5007 participants. CVD risk score in mid-adolescence was associated with depressive symptoms in early-adulthood (adjusted beta=0.06; standard error (SE)=0.02; p<0.001). Depressive symptoms in childhood were not associated with CVD risk score in mid-adolescence (adjusted beta=0.03; SE=0.02; p=0.11). Childhood inflammatory markers were associated with CVD risk score in mid-adolescence. Adolescent CVD risk score mediated the associations between childhood inflammatory markers and depressive symptoms in early-adulthood.

LIMITATIONS

The cohort primarily comprises White individuals, limiting generalisability. Sample attrition required imputation for missing data.

CONCLUSIONS

Association between CVD risk and depression in childhood/adolescence is unidirectional, with higher CVD risk increasing the risk of depressive symptoms. Childhood inflammation may increase risk of depression by influencing adolescent CVD risk.