Obstetric complications and risk for conversion to psychosis among individuals at high clinical risk

Clinical and neurodevelopmental predictors of psychotic disorders in children and adolescents at clinical high risk for psychosis: the CAPRIS study

BACKGROUND

The neurodevelopmental hypothesis of schizophrenia represents the disorder as an expression of an alteration during the brain development process early in life. Neurodevelopmental variables could become a trait marker, and the study of these variables in children and adolescents at clinical high risk for psychosis (CHR) could identify a specific cluster of patients who later developed psychosis. The aim of this study is to describe clinical and neurodevelopment predictors of transition to psychosis in child and adolescent participants at CHR. Naturalistic longitudinal two-center study of 101 CHR and 110 healthy controls (HC) aged 10-17. CHR participants were children and adolescents aged 10-17, meeting one or more of the CHR criteria assessed at baseline and at 18 months' follow-up. Neurodevelopmental variables assessed were obstetric complications, delay in principal development milestones, and presence of a neurodevelopment diagnosis. Pairwise comparisons, linear regressions, and binary logistic regression were performed.A transition rate of 23.3% at 1.5 years was observed. Participants who developed psychosis (CHR-P) showed higher rates of grandiosity and higher proportions of antipsychotic medication intake at baseline compared to participants who did not develop a psychotic disorder (CHR-NP). In terms of neurodevelopment alterations, CHR-P group showed a higher proportion of participants reporting delay in language development than the CHR-NP and HC groups. The odds of psychosis increased by 6.238 CI 95% [1.276-30.492] for a one-unit increase in having a positive score in grandiosity; they increased by 4.257 95% CI [1.293-14.023] for a one-unit increase in taking antipsychotic medication, and by 4.522 95% [1.185-64.180] for showing language development delay. However, the p-values did not reach significance after adjusting for multiple comparisons.A combination of clinical and neurodevelopmental alterations could help predict the transition to psychotic disorder in a CHR child and adolescent sample. Our results suggest the potential utility of collecting information about neurodevelopment and using these variable multifactorial models to predict psychosis disorders.

Neurodevelopmental disturbances in schizophrenia: evidence from genetic and environmental factors

Since more than 3 decades, schizophrenia (SZ) has been regarded as a neurodevelopmental disorder. The neurodevelopmental hypothesis proposes that SZ is associated with genetic and environmental risk factors, which influence connectivity in neuronal circuits during vulnerable developmental periods. We carried out a non-systematic review of genetic/environmental factors that increase SZ risk in light of its neurodevelopmental hypothesis. We also reviewed the potential impact of SZ-related environmental and genetic risk factors on grey and white matter pathology and brain function based on magnetic resonance imaging and post-mortem studies. Finally, we reviewed studies that have used patient-derived neuronal models to gain knowledge of the role of genetic and environmental factors in early developmental stages. Taken together, these studies indicate that a variety of environmental factors may interact with genetic risk factors during the pre- or postnatal period and/or during adolescence to induce symptoms of SZ in early adulthood. These risk factors induce disturbances of macro- and microconnectivity in brain regions involving the prefrontal, temporal and parietal cortices and the hippocampus. On the molecular and cellular level, a disturbed synaptic plasticity, loss of oligodendrocytes and impaired myelination have been shown in brain regions of SZ patients. These cellular/histological phenotypes are related to environmental risk factors such as obstetric complications, maternal infections and childhood trauma and genetic risk factors identified in recent genome-wide association studies. SZ-related genetic risk may contribute to active processes interfering with synaptic plasticity in the adult brain. Advances in stem cell technologies are providing promising mechanistic insights into how SZ risk factors impact the developing brain. Further research is needed to understand the timing of the different complex biological processes taking place as a result of the interplay between genetic and environmental factors.

Shaped before birth: Obstetric complications identify a more severe clinical phenotype among patients presenting a first affective or non-affective episode of psychosis

Obstetric complications (OCs) may contribute to the heterogeneity that characterizes psychiatric illness, particularly the phenotypic presentation of first episode psychoses (FEP). Our aim was to examine the relationship between OCs and socio-demographic, clinical, functioning and neuropsychological characteristics in affective and non-affective FEP. We performed a cross-sectional,study where we recruited participants with FEP between 2011 and 2021, and retrospectively assessed OCs using the Lewis-Murray scale. OCs were used as a dichotomous variable and further stratified into three subtypes: complications of pregnancy, abnormal fetal growth and development, and difficulties in delivery. We performed a logistic stepwise forward regression analysis to examine variables associated with the presence of OCs. Of the 104 participants (67 affective FEP and 37 non-affective FEP), 31.7% (n = 33) had experienced OCs. Subjects with OCs showed a more gradual emergence of prodromal symptoms as well as higher negative and total Positive and Negative Syndrome Scale (PANSS) scores. In the multivariate analysis, the presence of OCs was independently associated with a younger age at first episode of any type (OR = 0.904, p = 0.003) and slower emergence of prodromal symptoms (OR = 0.274, p = 0.011). When considering specific types of OCs, those related with fetal growth were associated with worse neuropsychological performance, while OCs at delivery were related to earlier onset of illness and more severe symptoms. In conclusion, OCs signaled a specific FEP phenotype characterized by earlier and more protracted onset of illness as well as more burdensome symptoms, independently of FEP type (i.e., affective vs non-affective). These results indicate a potential target of early intervention in FEP.

Prenatal Maternal Stress and the Cascade of Risk to Schizophrenia Spectrum Disorders in Offspring

PURPOSE OF REVIEW

Disruptions in fetal development (via genetic and environmental pathways) have been consistently associated with risk for schizophrenia in a variety of studies. Although multiple obstetric complications (OCs) have been linked to schizophrenia, this review will discuss emerging evidence supporting the role of prenatal maternal stress (PNMS) in the etiology of schizophrenia spectrum disorders (SSD). In addition, findings linking PNMS to intermediate phenotypes of the disorder, such as OCs and premorbid cognitive, behavioral, and motor deficits, will be reviewed. Maternal immune and endocrine dysregulation will also be explored as potential mechanisms by which PNMS confers risk for SSD.

RECENT FINDINGS

PNMS has been linked to offspring SSD; however, findings are mixed due to inconsistent and retrospective assessments of PNMS and lack of specificity about SSD outcomes. PNMS is also associated with various intermediate phenotypes of SSD (e.g., prenatal infection/inflammation, decreased fetal growth, hypoxia-related OCs). Recent studies continue to elucidate the impact of PNMS while considering the moderating roles of fetal sex and stress timing, but it is still unclear which aspects of PNMS (e.g., type, timing) confer risk for SSD specifically. PNMS increases risk for SSD, but only in a small portion of fetuses exposed to PNMS. Fetal sex, genetics, and other environmental factors, as well as additional pre- and postnatal insults, likely contribute to the PNMS-SSD association. Longitudinal birth cohort studies are needed to prospectively illuminate the mechanisms that account for the variability in outcomes following PNMS.

A history of obstetric complications is associated with the risk of progression from an at risk mental state to psychosis

OBJECTIVE

Clinical criteria for diagnosing Clinical High Risk for psychosis are now available. However, an understanding of the factors modulating the risk of subsequent development of frank psychosis in "at risk" individuals remains elusive. The aim of the study was to identify associations between obstetric history and the development of psychotic disorders in individuals with an At Risk Mental State (ARMS).

METHODS

Obstetric data was obtained from the medical records of 82 individuals meeting ARMS criteria. The participants were followed up for a mean period of 42.3 (±28.3) months for transition to psychosis.

RESULTS

A history of at least one obstetric complication (OC) endorsed as definite on the Lewis and Murray Obstetric Complications Scale was found to be associated with increased risk of transition to schizophrenia (OR: 6.57, 95% CI:1.89-22.85). The number of definite OCs was found to be positively correlated with the proportion of converters (p<0.0001). The probability of conversion to schizophrenia was found to increase with a decrease of Apgar-1 and Apgar-5 scores (ORs: 0.40, 95% CI:0.22-0.74 and 0.25, 95% CI:0.10-0.63, respectively).

CONCLUSIONS

The findings emphasise the potential value of including obstetric data in algorithms estimating the likelihood of transition of an ARMS to full-blown psychosis.

The impact of environmental factors in severe psychiatric disorders

During the last decades, schizophrenia has been regarded as a developmental disorder. The neurodevelopmental hypothesis proposes schizophrenia to be related to genetic and environmental factors leading to abnormal brain development during the pre- or postnatal period. First disease symptoms appear in early adulthood during the synaptic pruning and myelination process. Meta-analyses of structural MRI studies revealing hippocampal volume deficits in first-episode patients and in the longitudinal disease course confirm this hypothesis. Apart from the influence of risk genes in severe psychiatric disorders, environmental factors may also impact brain development during the perinatal period. Several environmental factors such as antenatal maternal virus infections, obstetric complications entailing hypoxia as common factor or stress during neurodevelopment have been identified to play a role in schizophrenia and bipolar disorder, possibly contributing to smaller hippocampal volumes. In major depression, psychosocial stress during the perinatal period or in adulthood is an important trigger. In animal studies, chronic stress or repeated administration of glucocorticoids have been shown to induce degeneration of glucocorticoid-sensitive hippocampal neurons and may contribute to the pathophysiology of affective disorders. Epigenetic mechanisms altering the chromatin structure such as histone acetylation and DNA methylation may mediate effects of environmental factors to transcriptional regulation of specific genes and be a prominent factor in gene-environmental interaction. In animal models, gene-environmental interaction should be investigated more intensely to unravel pathophysiological mechanisms. These findings may lead to new therapeutic strategies influencing epigenetic targets in severe psychiatric disorders.

Obstetric complications in early psychosis: relation with family history of psychosis

The people classified as being at ultra-high risk (UHR) of developing psychosis are expected to share many risk factors for psychosis with the patients diagnosed with schizophrenia, including an enhanced incidence of obstetric complications (OCs). This study set out to investigate the incidence and correlates of OCs in a sample of patients accessing an early intervention center. Patients' mothers were asked whether they had suffered from any somatic complication during pregnancy from a list of OCs with potential direct relevance to the physical wellbeing of the offspring. Out of 86 patients diagnosed with first-episode psychosis, 20 (23%) cases were positive for the occurrence of severe OCs, as reported by their mothers during an interview; out of 83 UHR patients, 21 (25%) cases were positive for OCs. OCs were more common in individuals with a family history of psychosis than in those without such a history. OCs might interact with genetic vulnerability to increase the risk of psychosis. Lack of comparison to healthy controls is a limitation that decreases the value of these findings.

Dermatoglyphic asymmetries and fronto-striatal dysfunction in young adults reporting non-clinical psychosis

OBJECTIVE

Growing evidence indicates that non-clinical psychotic-like experiences occur in otherwise healthy individuals, suggesting that psychosis may occur on a continuum. However, little is known about how the diathesis for formal psychosis maps on to individuals at the non-clinical side of this continuum. Our current understanding of the pathophysiology of schizophrenia implicates certain key factors such as early developmental abnormalities and fronto-striatal dysfunction. To date, no studies have examined these core factors in the context of non-clinical psychosis.

METHOD

A total of 221 young adults were assessed for distressing attenuated positive symptoms (DAPS), dermatoglyphic asymmetries (a marker of early developmental insult), and procedural memory (a proxy for fronto-striatal function).

RESULTS

Participants reporting DAPS (n = 16; 7.2%) and no-DAPS (n = 205; 92.7%) were split into two groups. The DAPS group showed significantly elevated depression, elevated dermatoglyphic asymmetries, and a pattern of procedural learning consistent with other studies with formally psychotic patients.

CONCLUSION

The results indicate that the non-clinical side of the psychosis continuum also shares key vulnerability factors implicated in schizophrenia, suggesting that both early developmental disruption and abnormalities in fronto-striatal function are core aspects underlying the disorder.

Premorbid multivariate markers of neurodevelopmental instability in the prediction of adult schizophrenia-spectrum disorder: a high-risk prospective investigation

The authors examined whether multiple childhood indicators of neurodevelopmental instability known to relate to schizophrenia-spectrum disorders could predict later schizophrenia-spectrum outcomes. A standardized battery of neurological and intellectual assessments was administered to a sample of 265 Danish children in 1972, when participants were 10-13 years old. Parent psychiatric diagnoses were also obtained in order to evaluate the predictive strength of neurodevelopmental factors in combination with genetic risk. Adult diagnostic information was available for 244 members of the sample. Participants were grouped into three categories indicating level of genetic risk: children with a parent with schizophrenia (n=94); children with a parent with a non-psychotic mental health diagnosis (n=84); and children with a parent with no records of psychiatric hospitalization (n=66). Variables measured included minor physical anomalies (MPAs), coordination, ocular alignment, laterality, and IQ. Adult diagnoses were assessed through psychiatric interviews in 1992, as well as through a scan of the national psychiatric registry through 2007. Through a combination of multiple childhood predictors, the model correctly classified 73% (24 of 33) of the participants who eventually developed a schizophrenia-spectrum outcome in adulthood. Results suggest that, with replication, multivariate premorbid prediction could potentially be a useful complementary approach to identifying individuals at risk for developing a schizophrenia-spectrum disorder. Genetic risk, MPAs, and other markers of neurodevelopmental instability may be useful for comprehensive prediction models.

Minor physical anomalies and vulnerability in prodromal youth

Because both the brain and craniofacial/limb features originate from the same germinal layer during early gestation, the postnatal presence of minor physical anomalies (MPAs) involving these physical features may be indicative of defects in prenatal neural migration and consequent brain abnormalities among individuals with psychosis. However, to date it is unknown what symptoms and characteristics MPAs may be associated with, or how these markers may reflect vulnerability among adolescents at high-risk for developing psychosis. This information is particularly vital for understanding susceptibility and informing etiological conceptualizations such as the neural diathesis-stress model. In this study, 50 adolescents with a prodromal syndrome were evaluated for MPAs, salivary cortisol, auditory and visual memory function, and attenuated positive, negative, and disorganized symptoms. Results indicated that the participants showing elevated MPAs (n=25) were distinguished by elevated cortisol, deficit immediate and delayed visual memory, and higher levels of disorganized prodromal symptoms when compared with those participants exhibiting a lower incidence of MPAs. This was supported by supplementary correlational analyses examining the entire sample. These findings provide preliminary support for a theory that MPAs may reflect hippocampal system vulnerability among prodromal patients.