The Kraepelinian Dichotomy From the Perspective of Prenatal Infectious and Immunologic Insults

Inflammation and emotion regulation: a narrative review of evidence and mechanisms in emotion dysregulation disorders

Emotion dysregulation (ED) describes a difficulty with the modulation of which emotions are felt, as well as when and how these emotions are experienced or expressed. It is a focal overarching symptom in many severe and prevalent neuropsychiatric diseases, including bipolar disorders (BD), attention deficit/hyperactivity disorder (ADHD), and borderline personality disorder (BPD). In all these disorders, ED can manifest through symptoms of depression, anxiety, or affective lability. Considering the many symptomatic similarities between BD, ADHD, and BPD, a transdiagnostic approach is a promising lens of investigation. Mounting evidence supports the role of peripheral inflammatory markers and stress in the multifactorial aetiology and physiopathology of BD, ADHD, and BPD. Of note, neural circuits that regulate emotions appear particularly vulnerable to inflammatory insults and peripheral inflammation, which can impact the neuroimmune milieu of the central nervous system. Thus far, few studies have examined the link between ED and inflammation in BD, ADHD, and BPD. To our knowledge, no specific work has provided a critical comparison of the results from these disorders. To fill this gap in the literature, we review the known associations and mechanisms linking ED and inflammation in general, and clinically, in BD, ADHD, and BD. Our narrative review begins with an examination of the routes linking ED and inflammation, followed by a discussion of disorder-specific results accounting for methodological limitations and relevant confounding factors. Finally, we critically discuss both correspondences and discrepancies in the results and comment on potential vulnerability markers and promising therapeutic interventions.

Assessing for prenatal risk factors associated with infant neurologic morbidity using a multivariate analysis

OBJECTIVE

To characterize the biochemical and demographic profiles of pregnant people with maternal immune activation (MIA) and identify the prenatal characteristics associated with neurologic morbidity in offspring.

STUDY DESIGN

This was a retrospective cohort study of 602 mother-infant dyads with births between 2009 and 2010 in California. Multivariable logistic regression was used to build a MIA vulnerability profile including mid-pregnancy biochemical markers and maternal demographic characteristics, and its relationship with infant neurologic morbidity was examined.

RESULTS

Of the 602 mother-infant dyads, 80 mothers and 61 infants had diagnoses suggestive of MIA and neurologic morbidity, respectively. Our model, including two demographic and seven biochemical characteristics, identified mothers with MIA with good performance (AUC:0.814; 95% CI:0.7-0.8). Three demographic and five inflammatory markers together identified 80% of infants with neurological morbidity (AUC:0.802, 95% CI:0.7-0.8).

CONCLUSION

Inflammatory environment in mothers with pre-existing risk factors like obesity, poverty, and prematurity renders offspring more susceptible to neurologic morbidities.

Low peripheral mitochondrial DNA copy number during manic episodes of bipolar disorders is associated with disease severity and inflammation

Mitochondria (Mt) are intra-cellular components essential for cellular energy processes whose dysfunction may induce premature cellular senescence and/or inflammation, both observed in bipolar disorders (BD). We investigated mitochondrial DNA copy number (mtDNAcn) levels in patients with BD being in manic, depressive or euthymic phase and in healthy controls (HC) both characterized for the levels of blood-based inflammatory markers and stigma of pathogens. 312 patients with BD were compared to 180 HC. mtDNAcn were measured using a digital droplet PCR. Serum levels of 14 inflammatory molecules and 3 anti-infectious IgG stigma were respectively evaluated by electro-chemiluminescence, ELISA and dedicated immunoassays. The statistical analyses were performed using Spearman's correlation, Wilcoxon signed-rank and Kruskal-Wallis rank sum tests. P-values were adjusted for multiple testing with Benjamini-Hochberg method. We found low levels of mtDNAcn in BD patients as compared to HC (P = 0.008) especially during manic episodes (P = 0.0002). We also observed that low levels of mtDNAcn are negatively correlated with mood and psychotic scales (PANSS, YMRS and CGI) (adjusted P (Adj P) = 0.02, 0.003 and 0.05 respectively) and positively with the GAF severity scale (Adj P = 0.002). They were also correlated with high levels of both intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 (Adj P = 0.003 and 0.001) along with a trend toward increased IL-2, IL-10 and B2M circulating levels (Adj P = 0.05). Here, we report correlations between marker of mitochondria functioning and both clinical scales and inflammatory markers in BD patients experiencing manic episodes. If replicated, these finding might allow to predict transition between disease phases and to design accurate therapeutic options.

Schizophrenia and Influenza at the Centenary of the 1918-1919 Spanish Influenza Pandemic: Mechanisms of Psychosis Risk

Associations between influenza infection and psychosis have been reported since the eighteenth century, with acute "psychoses of influenza" documented during multiple pandemics. In the late 20th century, reports of a season-of-birth effect in schizophrenia were supported by large-scale ecological and sero-epidemiological studies suggesting that maternal influenza infection increases the risk of psychosis in offspring. We examine the evidence for the association between influenza infection and schizophrenia risk, before reviewing possible mechanisms via which this risk may be conferred. Maternal immune activation models implicate placental dysfunction, disruption of cytokine networks, and subsequent microglial activation as potentially important pathogenic processes. More recent neuroimmunological advances focusing on neuronal autoimmunity following infection provide the basis for a model of infection-induced psychosis, potentially implicating autoimmunity to schizophrenia-relevant protein targets including the N-methyl-D-aspartate receptor. Finally, we outline areas for future research and relevant experimental approaches and consider whether the current evidence provides a basis for the rational development of strategies to prevent schizophrenia.

Inflammation as a Mechanism of Bipolar Disorder Neuroprogression

Bipolar disorder (BD) is a severe, debilitating psychiatric condition with onset in adolescence or young adulthood and often follows a relapsing and remitting course throughout life. The concept of neuroprogression in BD refers to the progressive path with an identifiable trajectory that takes place with recurrent mood episodes, which eventually leads to cognitive, functional, and clinical deterioration in the course of BD. Understanding the biological basis of neuroprogression helps to explain the subset of BD patients who experience worsening of their disorder over time. Additionally, the study of the neurobiological mechanisms underpinning neuroprogression will help BD staging based on systems biology. Replicated epidemiological studies have suggested inflammatory mechanisms as primary contributors to the neuroprogression of mood disorders. It is known that dysregulated inflammatory/immune pathways are often associated with BD pathophysiology. Hence, in this chapter, we focus on the evidence for the involvement of inflammation and immune regulated pathways in the neurobiological consequences of BD neuroprogression. Herein we put forth the evidence of immune markers from autoimmune disorders, chronic infections, and gut-brain axis that lead to BD neuroprogression. Further, we highlighted the peripheral and central inflammatory components measured along with BD progression.

GWAS SNPs Impact Shared Regulatory Pathways Amongst Multimorbid Psychiatric Disorders and Cognitive Functioning

Background: Epidemiological research has reported that attention-deficit hyperactivity disorder (ADHD), anxiety, bipolar disorder (BD), schizophrenia (SCZ), and unipolar depression (UD) are multimorbid conditions that are typically accompanied by cognitive advantages or deficits, suggesting that common biological mechanisms may underlie these phenotypes. Genome-wide association studies (GWAS) have identified single-nucleotide polymorphisms (SNPs) associated with psychiatric disorders and cognitive functioning. However, the mechanisms by which these SNPs contribute to multimorbidities amongst psychiatric and cognitive phenotypes remains largely unknown. Objective: To identify shared regulatory mechanisms amongst multimorbid psychiatric disorders and cognitive functioning. Methods: We integrated data on 3D genome organization, expression quantitative trait loci (eQTLs), and pathway analyses to identify shared and specific regulatory impacts of 2,893 GWAS SNPs (p < 1 × 10^-6) associated with ADHD, anxiety, BD, SCZ, UD, and cognitive functioning on genes and biological pathways. Drug-gene interaction analysis was performed to identify potential pharmacological impacts on these genes and pathways. Results: The analysis revealed 33 genes and 62 pathways that were commonly affected by tissue-specific gene regulatory interactions associated with all six phenotypes despite there being no common SNPs in our original dataset. The analysis of brain-specific regulatory connections revealed similar patterns at eQTL and eGene levels, but no pathways shared by all six phenotypes. Instead, pairwise overlaps and individualized pathways were identified for psychiatric and cognitive phenotypes in brain tissues. Conclusions: This study offers insight into the shared genes and biological pathways that are affected by tissue-specific regulatory impacts resulting from psychiatric- and cognition-associated genetic variants. These results provide limited support for the "p-factor" hypothesis for psychiatric disorders and potential mechanisms that explain drug side-effects. Our results highlight key biological pathways for development of therapies that target single or multiple psychiatric and cognitive phenotypes.

120th Anniversary of the Kraepelinian Dichotomy of Psychiatric Disorders

PURPOSE OF REVIEW

Emil Kraepelin, in 1899, proposed a dichotomy of psychiatric disorders into "dementia praecox," further called schizophrenia, and "manisch-depressives Irresein," now conceptualized as a bipolar disorder. The purpose of the review is to show both similarities and differences between disorders involved in this dichotomy, speaking for and against the idea.

RECENT FINDINGS

On the molecular genetic side, there are data for both a genetic overlap and genetic differences between these two illnesses. Among pharmacological treatment, lithium, valproates, and carbamazepine present evidence for Kraepelinian dichotomy while atypical antipsychotics speak against this. The recent results for similarities and differences in the immune system, cognitive functions, and neurodevelopmental mechanisms have also been presented and discussed. As of 2019, the Kraepelinian dichotomy has been still partly valid although the results of recent clinical, neurobiological, and pharmacological studies provided a large number of data for an intermediate space between schizophrenia and bipolar disorder.

Maternal Immune Activation and Neuropsychiatric Illness: A Translational Research Perspective

Epidemiologic studies, including prospective birth cohort investigations, have implicated maternal immune activation in the etiology of neuropsychiatric disorders. Maternal infectious pathogens and inflammation are plausible risk factors for these outcomes and have been associated with schizophrenia, autism spectrum disorder, and bipolar disorder. Concurrent with epidemiologic research are animal models of prenatal immune activation, which have documented behavioral, neurochemical, neuroanatomic, and neurophysiologic disruptions that mirror phenotypes observed in these neuropsychiatric disorders. Epidemiologic studies of maternal immune activation offer the advantage of directly evaluating human populations but are limited in their ability to uncover pathogenic mechanisms. Animal models, on the other hand, are limited in their generalizability to psychiatric disorders but have made significant strides toward discovering causal relationships and biological pathways between maternal immune activation and neuropsychiatric phenotypes. Incorporating these risk factors in reverse translational animal models of maternal immune activation has yielded a wealth of data supporting the predictive potential of epidemiologic studies. To further enhance the translatability between epidemiology and basic science, the authors propose a complementary approach that includes deconstructing neuropsychiatric outcomes of maternal immune activation into key pathophysiologically defined phenotypes that are identifiable in humans and animals and that evaluate the interspecies concordance regarding interactions between maternal immune activation and genetic and epigenetic factors, including processes involving intergenerational disease transmission. [AJP AT 175: Remembering Our Past As We Envision Our Future October 1857: The Pathology of Insanity J.C. Bucknill: "In the brain the state of inflammation itself either very quickly ceases or very soon causes death; but when it does cease it leaves behind it consequences which are frequently the causes of insanity, and the conditions of cerebral atrophy." (Am J Psychiatry 1857; 14:172-193 )].

A Bayesian model comparison approach to test the specificity of visual integration impairment in schizophrenia or psychosis

Impaired visual integration is well documented in schizophrenia and related to functional outcomes. However, it is unclear if this deficit is specific to schizophrenia, or characteristic of psychosis more broadly. To address this question, this study used a Bayesian model comparison approach to examine the evidence of three grouping models of visual integration performance in 116 individuals with schizophrenia (SZ), schizoaffective disorder (SA), bipolar disorder (BD) with or without a history of prominent psychosis (BDP+ and BDP-, respectively), or no psychiatric diagnosis (healthy controls; HC). We compared: (1) Psychosis Model (psychosis, non-psychosis), where the psychosis group included SZ, SA, and BDP+, and the non-psychosis group included BDP- and HC; (2) Schizophrenia Model (SZ, non-SZ); and (3) DSM Model (SZ, SA, BD, HC). The relationship between visual integration and general cognition was also explored. The Psychosis Model showed the strongest evidence, and visual integration was associated with general cognition in participants with psychosis. The results were consistent with the Research Domain Criteria (RDoC) framework, indicating that visual integration impairment is characteristic of psychosis and not specific to SZ or DSM categories, and may share similar disease pathways with observed neurocognitive deficits in psychotic disorders.

Peptide Sharing Between Viruses and DLX Proteins: A Potential Cross-Reactivity Pathway to Neuropsychiatric Disorders

The present study seeks to determine potential associations between viral infections and neuropsychiatric diseases. To address this issue, we investigated the peptide commonalities between viruses that have been related to psychiatric and neurological disorders—such as rubella, human immunodeficiency virus, and herpesviruses—and human distal-less homeobox (DLX) proteins expressed in developing brain—namely, DLX1, DLX2, DLX5, and DLX6. Peptide matching analyses revealed a high degree of pentapeptide sharing. From an immunological perspective, this overlap is relevant because pentapeptides are endowed with immunogenicity and antigenicity—that is, they are immune determinants. Moreover, infection-induced immune cross-reactions might have functional, spatial, and temporal implications related to the functions and expression patterns of DLX1 and DLX5 in the fetal and adult human brain. In sum, our data support the hypothesis that viral infections may be linked to neuropsychiatric diseases through autoimmune cross-reactions caused by molecular mimicry between viral proteins and brain-specific DLX self-antigens.

Assessment of Complement Cascade Components in Patients With Bipolar Disorder

Introduction: The immune system is undoubtedly involved in the pathogenesis of various psychiatric disorders, such as schizophrenia, bipolar disorder, or depression. Although its role is not fully understood, it appears that this area of research can help to understand the etiology of mental illness. One of the components of the human immune system is the complement system, which forms a part of the innate immune response. Physiologically, except for its essential protective role, it is a vital element in the regeneration processes, including neurogenesis. To date, few studies have tried to clarify the role of the complement cascade in mental disorders. Materials and Methods: We evaluated concentrations of C3a, C5a, and C5b-9 complement cascade components in the peripheral blood of 30 patients suffering from bipolar disorder (BD) for at least 10 years, in euthymia, who were not treated with lithium salts. In addition, we divided our study sample into BD type I (BD-I, 22 persons), and BD type II (BD-II, 8 patients). The control group consisted of 30 healthy volunteers matched for age, sex, BMI, and smoking habits. Results: Compared to healthy controls, BD patients had elevated concentrations of all the investigated components. Furthermore, in patients with BD-II, we observed higher concentrations of C5b-9 as compared to patients with BD-I. However, there was a significant effect of BD diagnosis only on the levels of C3a and C5a but not on the level of C5b-9 after adjustment for potential confounding factors. Conclusions: Increased concentrations of components C3a and C5a of the complement system in the investigated group as compared to healthy controls suggest involvement of the complement cascade in the pathogenesis of BD, and provides further evidence of immune system dysregulation in BD patients.

Childhood maltreatment severity is associated with elevated C-reactive protein and body mass index in adults with schizophrenia and bipolar diagnoses

BACKGROUND

Several studies have described an association between childhood maltreatment and inflammatory markers in the psychotic disorders (schizophrenia [SZ] and bipolar disorder [BD]). Previous studies have been relatively small (<50 participants), and the severity of abuse and the putative influence of body mass index (BMI) have not been properly investigated.

METHODS

The combined effects of childhood abuse severity and clinical diagnosis on inflammatory markers were investigated in a large sample (n=483) of patients with a disorder on the psychosis spectrum and in healthy controls (HCs). Plasma levels of inflammatory markers (high-sensitivity C-reactive protein [hs-CRP], soluble tumor necrosis factor receptor type 1 [TNFR-R1], glycoprotein 130 [gp130]) were analyzed, and BMI and data on childhood trauma events, on the basis of the Childhood Trauma Questionnaire (CTQ), were obtained from all participants.

RESULTS

Patients had increased levels of hs-CRP (P<0.001, Cohens d=0.4), lower levels of gp130 (P<0.001, Cohens d=0.5), higher BMI (P<0.001, Cohens d=0.5) and reported more childhood maltreatment experiences (P<0.001, Cohens d=1.2) than the HC group. The severity of childhood abuse (up to three types of abuse: sexual abuse, physical abuse, and emotional abuse) was associated with elevated BMI (f=8.46, P<0.001, Cohen's d=0.5) and hs-CRP (f=5.47, P=0.001, Cohen's d=0.3). Combined effects of patient status and severity of childhood abuse were found for elevated hs-CRP (f=4.76, P<0.001, Cohen's d=0.4). Differences among the groups disappeared when BMI was added to the model.

DISCUSSION

Trauma-altered immune activation via elevated hs-CRP in patients with SZ and BD may be mediated by higher BMI; however, the direction of this association needs further clarification.

Maternal serum cytokine levels and risk of bipolar disorder

Prenatal exposure to influenza has previously been associated with increased risk of bipolar disorder (BD), an association that may be mediated by maternal cytokines. The objective of this study was to determine the association between maternal levels of cytokines measured during each trimester of pregnancy and the risk of BD in offspring. We conducted a case-control study nested in the Child Health and Development Study, a birth cohort that enrolled pregnant women in 1959-1966. Potential cases with DSM-IV-TR bipolar I disorder, bipolar II disorder, BD not otherwise specified, and BD with psychotic features were ascertained through electronic medical records, a public agency database, and a mailing to the cohort. Diagnoses were confirmed by clinical interview. Nine cytokines (IL-1β, IL-4, IL-5, IL-6, IL-8, IL-10, IFN-γ, TNF-α and GM-CSF) were measured simultaneously by Luminex assays in archived prenatal maternal serum samples from 85 cases and 170 matched controls. Data were analyzed using conditional logistic regression. In the overall study sample, there were no significant associations between prenatal maternal cytokine levels and BD after adjustment for confounders. The risk of BD without psychotic features was decreased among subjects with higher maternal levels of first trimester log-transformed IL-4 (OR (95% CI)=0.76 (0.58, 0.98); p=0.04) and third trimester log-transformed IL-6 (OR (95% CI)=0.64 (0.42, 0.98); p=0.04). In conclusion, higher levels of prenatal maternal cytokines were not associated with increased risk for BD. Further studies with larger samples are necessary to confirm the finding.

Maternal immune activation during pregnancy in rats impairs working memory capacity of the offspring

Maternal immune activation during pregnancy is an environmental risk factor for psychiatric illnesses such as schizophrenia in the offspring. Patients with schizophrenia display an array of cognitive symptoms, including impaired working memory capacity. Rodent models have been developed to understand the relationship between maternal immune activation and the cognitive symptoms of schizophrenia. The present experiment was designed to test whether maternal immune activation with the viral mimetic polyinosinic:polycytidylic acid (polyI:C) during pregnancy affects working memory capacity of the offspring. Pregnant Long Evans rats were treated with either saline or polyI:C (4mg/kg; i.v.) on gestational day 15. Male offspring of the litters (2-3months of age) were subsequently trained on a nonmatching-to-sample task with odors. After a criterion was met, the rats were tested on the odor span task, which requires rats to remember an increasing span of different odors to receive food reward. Rats were tested using delays of approximately 40s during the acquisition of the task. Importantly, polyI:C- and saline-treated offspring did not differ in performance of the nonmatching-to-sample task suggesting that both groups could perform a relatively simple working memory task. In contrast, polyI:C-treated offspring had reduced span capacity in the middle and late phases of odor span task acquisition. After task acquisition, the rats were tested using the 40s delay and a 10min delay. Both groups showed a delay-dependent decrease in span, although the polyI:C-treated offspring had significantly lower spans regardless of delay. Our results support the validity of the maternal immune activation model for studying the cognitive symptoms of neurodevelopmental disorders such as schizophrenia.

Gestational maternal C--reactive protein and risk of bipolar disorder among young individuals in a Nationwide Birth Cohort

OBJECTIVES

C-reactive protein (CRP) is a well-established general marker of inflammation from both infectious and noninfectious exposures. Previous studies have shown that maternal CRP is associated with an increased risk of autism and schizophrenia. The aim of this study was to examine the association between early to mid-gestational serum CRP levels, prospectively assayed in maternal sera, and the risk of bipolar disorder (BPD).

METHODS

This study is derived from the Finnish Prenatal Study of Bipolar Disorder (FIPS-B), based on a nested case-control study design. A total of 378 BPD cases and 378 controls, matched on date of birth and sex, with available maternal sera were identified from Finnish nationwide registers. Maternal CRP levels were assessed using a latex immunoassay from archived maternal serum specimens, collected primarily during the first and second trimesters of pregnancy.

RESULTS

Increasing maternal CRP, examined as a continuous variable, was not associated with BPD (OR=0.92, 95% CI: 0.81-1.05, p=0.24). The result did not change appreciably following adjustment for potential confounders. There were no associations between CRP in the highest quintile or decile, compared with their respective reference groups, and BPD.

LIMITATIONS

The limitations of the study include: relative young age of the cohort and availability only of a single marker of inflammation.

CONCLUSIONS

In contrast to previous findings on schizophrenia and autism, gestational maternal serum CRP levels were not associated with an increased risk of BPD. It is likely that maternal inflammation may be an additional factor that differentiates schizophrenia from BPD.

Immuno-psychiatry: an agenda for clinical practice and innovative research

BACKGROUND

The diagnostic scheme for psychiatric disorders is currently based purely on descriptive nomenclature given that biomarkers subtypes and clearly defined causal mechanisms are lacking for the vast majority of disorders. The emerging field of "immuno-psychiatry" has the potential to widen the exploration of a mechanism-based nosology, possibly leading to the discovery of more effective personalised treatment strategies.

DISCUSSION

Disturbances in immuno-inflammatory and related systems have been implicated in the aetiology, pathophysiology, phenomenology and comorbidity of several psychiatric disorders, including major mood disorders and schizophrenia. A fundamental challenge in their clinical management is to identify bio-signatures that might indicate risk, state, trait, prognosis or theragnosis. Here, we provide the rationale for a clinical and research agenda to refine future clinical practice and conceptual views, and to delineate pathways toward innovative treatment discovery.

CONCLUSION

The development of bio-signatures will allow clinicians to tailor interventions to the abovementioned biomarker subtypes - a major translational goal for research in this field.

Kynurenine and Tryptophan Levels in Patients With Schizophrenia and Elevated Antigliadin Immunoglobulin G Antibodies

OBJECTIVE

Several studies have reported an association between nonceliac gluten sensitivity and schizophrenia. Immune and kynurenine (KYN) pathways have also been implicated in the pathophysiology of schizophrenia, and certain proinflammatory immune mediators may increase KYN and reduce tryptophan (TRP) levels.

METHODS

We measured serum antigliadin immunoglobulin G (IgG), KYN, and TRP in 950 patients with schizophrenia. Patients with antibody level at the 90th percentile or higher of control participants (21.9% of all patients) were classified as having elevated antigliadin IgG. Independent t tests and linear regression models were used to compare TRP, KYN, and KYN-TRP ratio (indicator of TRP metabolism) between patients with and those without elevated antigliadin IgG. The correlation between antigliadin IgG and TRP, KYN, and the ratio was also evaluated in the patients.

RESULTS

KYN and KYN-TRP ratio were higher in patients with elevated antigliadin IgG (geometric mean [standard deviation {SD}] = 2.65 [0.25] µmol/L versus 2.25 [0.23] µmol/L [p < .001] and 0.05 [0.26] versus 0.04 [0.25; p = .001] respectively), findings robust to adjustment for potential demographic and clinical confounders. Antigliadin IgG positively correlated with KYN and KYN-TRP ratio (r = 0.12, p < .001; r = 0.11, p = .002). TRP did not differ between the two groups and did not correlate with antigliadin IgG.

CONCLUSIONS

Our results connect nonceliac gluten sensitivity with the KYN pathway of TRP metabolism in psychotic illness and hint toward potential individualized treatment targets.

Maternal T. gondii, offspring bipolar disorder and neurocognition

Prenatal exposure to maternal Toxoplasma gondii (T. gondii) IgG antibody titer has been associated previously with an increased risk of offspring schizophrenia (SZ) and cognitive impairment. We examined maternal T. gondii, offspring bipolar disorder (BP) and childhood cognition using a population-based birth cohort. Maternal sera, drawn in the third trimester, were analyzed for T. gondii IgG antibody titer, and offspring cognition at ages 5 and 9-11 was measured with the Peabody Picture Vocabulary Test (PPVT) and the Raven Matrices (Raven). Raw scores were standardized and the ages combined. Potential cases with BP from the cohort were identified by database linkages. This protocol identified 85 cases who were matched 1:2 to controls. Maternal T. gondii IgG was not associated with the risk of BP in offspring. Neither moderate [HR=1.43 (CI: 0.49, 4.17)] nor high IgG titer [HR=1.6 [CI: 0.74, 3.48)] were associated with offspring BP. Associations were not observed between maternal T. gondii and BP with psychotic features or BP type 1. In addition, maternal T. gondii was not associated with childhood cognition. Our study suggests that T. gondii may be specific to SZ among major psychotic disorders, though further studies with larger sample sizes are required.

Where Do Epigenetics and Developmental Origins Take the Field of Developmental Psychopathology?

The time is ripe for upgrading or rethinking the assumed paradigms for how we study developmental psychopathology. The classic transactional models appear robust but need specification in terms of biological and psychosocial processes. That specification is increasingly tractable due to developments in genetics, epigenetics, the measurement of psychosocial processes, and theory and data on developmental origins of health and disease. This essay offers a high-level view of where the field has been and where it may be going in regard to nosology and conceptions of etiology. Remarks seek to consider rapidly evolving contexts not only for children, but also for the science itself due to progress in our field and in neighboring fields. Illustrations are provided as to how syndromal nosology can be enriched and advanced by careful integration with biologically relevant behavioral dimensions and application of quantitative methods. It is concluded that a revised, forward-looking, transactional model of abnormal child psychology will incorporate prenatal and postnatal developmental programming, epigenetic mechanisms and their associated genotype x environment interactions, and inflammatory processes as a potential common mediator influencing numerous health and mental health conditions.