Neurodevelopmental liabilities in schizophrenia and affective disorders

Clinical characteristics and neuroimaging findings of seven patients with Dyke Davidoff Masson syndrome

Background

DDMS is a rare disease diagnosed by clinical and radiological characteristics. But the complexity of radiological and clinical manifestations of DDMS has become a challenge diagnostically. To date, the reported cases with DDMS had highly varied clinical manifestations including seizures, contralateral hemiplegia/hemiparesis, facial asymmetry, mental retardation, etc. In addition to typical clinical findings, some new characteristics have been recently added to the spectrum of DDMS. However, few cases have been reported to be associated with neuropsychiatric symptoms according to the literature. This study aimed to investigate the neuropsychiatric manifestations associated with Dyke-Davidoff-Masson syndrome (DDMS) and related imaging findings.

Methods

This study included 7 patients diagnosed with DDMS between 2014 and 2020. The clinical characteristics, neuropsychiatric manifestations, and radiological results were retrospectively evaluated.

Results

Seven patients (five males and two females) with a mean age of 28.0 ± 9.73 (range 15.0–41.0) years were included. Five patients were admitted to the psychiatric unit due to psychological and behavioral disorders. Two patients were referred to the neurology unit mainly due to epilepsy. Six patients had epileptic seizures, 4 had hemiplegia, 3 had mental retardation, 2 patients had external ear deformities, and 2 had facial asymmetry. Neuropsychiatric symptoms were presented in 6 (85.7 %) cases. Cases 2–6 developed affective disorders. Deficits in verbal communication, impairment of social interaction, lack of insight, adulia and hypobulia appeared in cases 1–4. Schizophrenia with apathy, and epileptic schizoid psychosis were observed in cases 4 and 5 respectively. Case 6 had behavioral disorders, hyperactivity, tic disorder, mental retardation, anxiety, catatonic symptoms and suicidal tendency. Case 7 had seizures and mental retardation, and no psychiatric symptoms were presented. Radiological examinations showed unilateral cerebral atrophy, enlarged lateral ventricles, and various compensatory hypertrophy of the skull in all cases. The midline structure has shifted to the affected side in 5(71.4 %) cases. Atrophy of the basal ganglia or brain stem was observed in 4(57.1 %) cases.

Conclusions

The hallmark imaging manifestations of DDMS facilitated the diagnosis in most cases. This study illustrated that a variety of psychoneurotic disorders and ear abnormalities were correlated with DDMS.

Minor Physical Anomalies in Bipolar Disorder-A Meta-Analysis

Introduction: Minor physical anomalies (MPAs) may reflect basic neurobiological features underlying bipolar disorders (BPD), as they are sensitive physical indicators of morphogenetic failure of the brain. Despite several researches about the presence of MPAs in BPD, the results are still controversial. Objectives: The aim of the present meta-analysis was to assess the standardized weighted mean effect sizes of MPAs in BPD and to examine if MPAs may be found predominantly in the head and/or facial regions in BPD patients compared to controls (HC). Methods: Four studies, involving 155 patients with BPD, and 187 HC, were involved in the analysis after searching the literature. For the investigation of MPAs in the peripheral (MPA-P) and in the head and facial regions (MPA-CF), two studies involving 121 BPD patients, and 133 HC passed the inclusion criteria. Results: The number of the MPAs in the BPD group was significantly higher compared to HC. Another important finding of the present study is that BPD patients' MPA-P scores do not significantly differ from those of the HC. In contrast, BPD patients' MPA-CF scores were found to be significantly higher compared to HC subjects. It is important to note that there was a low number of eligible publications included, which caused higher heterogeneity. Conclusions: Low quality of evidence suggests that MPAs are more common in patients with BPD than in HC and the higher rate of MPAs is found predominantly in the head and facial regions.

Minor physical anomalies in bipolar I and bipolar II disorders - Results with the Méhes Scale

Minor physical anomalies (MPAs) are external markers of abnormal brain development, so the more common appearence of these signs among bipolar I and bipolar II patients can confirm the possibility of a neurodevelopmental deficit in these illnesses. The aim of the present study was to investigate the rate and topological profile of minor physical anomalies in patients with bipolar I and - first in literature - with bipolar II disorders compared to matched healthy control subjects. Using a list of 57 minor physical anomalies (the Méhes Scale), 30 bipolar I and 30 bipolar II patients, while as a comparison 30 matched healthy control subjects were examined. Significant differences were detected between the three groups comparing the total number of minor physical anomalies, minor malformations and phenogenetic variants and in the cases of the ear and the mouth regions. The individual analyses of the 57 minor physical anomalies by simultaneous comparison of the three groups showed, that in the cases of furrowed tongue and high arched palate were significant differences between the three groups. The results can promote the concept, that a neurodevelopmental deficit may play a role in the etiology of both bipolar I and bipolar II disorders.

Minor physical anomalies in schizophrenia and bipolar I disorder and the neurodevelopmental continuum of psychosis

OBJECTIVES

Minor physical anomalies (MPAs) have been investigated by numerous studies in patients with schizophrenia in support of the neurodevelopmental hypothesis of the disorder, but have rarely been examined in patients with bipolar disorder or in direct comparisons between the two conditions. The main objective of the present study was to compare the prevalence of MPAs in psychiatrically healthy controls, patients with bipolar I disorder, and patients with schizophrenia.

METHODS

A slightly modified version of the Waldrop Physical Anomaly Scale was used to assess MPAs in psychiatrically healthy controls (n = 103), patients with bipolar I disorder (n = 61), and patients with schizophrenia (n = 128).

RESULTS

In five out of six topographic regions (mouth, feet, head, eyes, and ears) there was a pattern of lowest regional MPA scores in controls, intermediate in bipolar I disorder, and highest in schizophrenia. The cephalofacial composite score and the total MPA score showed the same pattern, with all between-group differences being statistically significant. Seven individual MPAs in the discriminant analysis model contributed independently to the prediction of the triple-dependent status of 'psychiatrically healthy control, bipolar I disorder patient, schizophrenia patient': high/arched palate, fine electric hair, large gap between first and second toes, third toe ≥ second toe, epicanthus, malformed ears, and furrowed tongue.

CONCLUSIONS

Our findings support the existence of a continuum of neurodevelopmental adversity within the clinical spectrum of psychosis, with bipolar I disorder occupying an intermediate position between psychiatric health and schizophrenia.

Discriminating value of total minor physical anomaly score on the Waldrop scale between patients with bipolar I disorder and normal controls

Minor physical anomalies (MPAs) are slight structural aberrations indicative of abnormal neurodevelopment. Most studies of MPAs in bipolar disorder have yielded limited results. We attempted to assess the potential value of MPAs as a classifying test in the status bipolar I patients vs. normal controls. Sixty one bipolar I patients and 103 controls were evaluated for MPAs using a slightly modified version of the Waldrop scale. The specificity, sensitivity and predictive value of different total MPA (MPA-T) scores were determined. The cut-off MPA-T scores that optimally discriminated patients from controls (exhibiting the most balanced sets of sensitivity, specificity, positive and negative predictive values) were MPA-T ≥ 4 and MPA-T ≥ 5. These values set a "border zone" in which bipolar I patients began to prevail significantly over controls. The latter presented most frequently with MPA-T ≤ 3 and rarely with MPA-T ≥ 6. Bipolar I patients prevailed among outliers (subjects with significantly higher MPA-T scores). Our data establish MPA-T score as a reliable index in distinguishing between bipolar I patients and normal controls and are consistent with the hypothesis of abnormal neurodevelopment in bipolar disorder.

Striatal development involves a switch in gene expression networks, followed by a myelination event: implications for neuropsychiatric disease

Because abnormal development of striatal neurons is thought to be the part of pathology underlying major psychiatric illnesses, we studied the expression pattern of genes involved in striatal development and of genes comprising key striatal-specific pathways, during an active striatal maturation period, the first two postnatal weeks in rat. This period parallels human striatal development during the second trimester, when prenatal stress is though to lead to increased risk for neuropsychiatric disorders. To identify genes involved in this developmental process, we used subtractive hybridization, followed by quantitative real-time PCR, which allowed us to characterize the developmental expression of over 60 genes, many not previously known to play a role in neuromaturation. Of these 12 were novel transcripts, which did not match known genes, but which showed strict developmental expression and may play a role in striatal neurodevelopment. An additional 89 genes were identified as strong candidates for involvement in this neurodevelopmental process. We show that during the first two postnatal weeks in rat, an early gene expression network, still lacking key striatal-specific signaling pathways, is downregulated and replaced by a mature gene expression network, containing key striatal-specific genes including the dopamine D1 and D2 receptors, conferring to these neurons their functional identity. Therefore, before this developmental switch, striatal neurons lack many of their key phenotypic characteristics. This maturation process is followed by a striking rise in expression of myelination genes, indicating a striatal-specific myelination event. Such strictly controlled developmental program has the potential to be a point of susceptibility to disruption by external factors. Indeed, this period is known to be a susceptibility period in both humans and rats.

Consequences of early life MK-801 administration: long-term behavioural effects and relevance to schizophrenia research

Animal models contribute significantly to advancing the understanding of schizophrenia neurobiology, in addition to being an important tool for the screening of antipsychotic potential of new compounds. However, the entire spectrum or all the symptoms manifested in schizophrenia cannot be straightforwardly reproduced in animals due to the complexity of the disorder, difference in mental capacities and behaviours, and the ability to quantify or measure the changes. Blockade of the NMDA receptor by the use of MK-801, a non-competitive NMDA receptor antagonist, during the early postnatal period has been proposed to be an experimental model which induces behavioural changes that mimic several aspects of the disorder. The long term behavioural profile arising from this early life manipulation is reviewed herein, with a specific focus on behaviours relevant to a schizophrenia-like condition. Some of the reported neurochemical changes are also compiled. Although this method may be suitable to model some aspects of schizophrenia in rodents, there are unmet areas which need to be addressed, notably the characterisation of its predictive value.

Gene expression profiling in rodent models for schizophrenia

The complex neurodevelopmental disorder schizophrenia is thought to be induced by an interaction between predisposing genes and environmental stressors. In order to get a better insight into the aetiology of this complex disorder, animal models have been developed. In this review, we summarize mRNA expression profiling studies on neurodevelopmental, pharmacological and genetic animal models for schizophrenia. We discuss parallels and contradictions among these studies, and propose strategies for future research.

Sex-specific cortisol levels in bipolar disorder and schizophrenia during mental challenge--relationship to clinical characteristics and medication

OBJECTIVE

Our objective was to examine the cortisol release during a mental challenge in severe mental disorders versus healthy controls (HC), analyzing effects of sex, clinical characteristics and medication, and comparing Bipolar Disorder (BD) to Schizophrenia (SCZ).

METHODS

Patients with BD and SCZ (n=151) were recruited from a catchment area. HC (n=98) were randomly selected from the same area. Salivary samples were collected before and after a mental challenge and cortisol levels determined.

RESULTS

During the challenge there was an interaction between group and sex (P = 0.015) with male patients having a blunted cortisol release compared to male HC (P = 0.037). Cortisol change did not differ significantly between BD and SCZ. In all patients, the cortisol change correlated with number of psychotic episodes (r = -0.23, P = 0.025), and in females patients, with number of depressive episodes (r = -0.33, P = 0.015). Patients using antidepressants had a greater cortisol release during challenge than those not using antidepressants (P = 0.043).

CONCLUSIONS

Male patients with severe mental disorders seem to have a uniform abnormal cortisol release during mental challenges which associates with clinical course, and with beneficial effects of antidepressants.

Vulnerability of synaptic plasticity in the complexin II knockout mouse to maternal deprivation stress

The alterations in brain function and structure seen in schizophrenia are mediated by genetics as well as vulnerability due to environmental factors. Postmortem studies in schizophrenic patients have shown that expression of complexin II, which is involved in neurotransmitter release at central nervous system synapses, is decreased in the brain. We examined the physiological characteristics of complexin II gene-deficient mice subjected to maternal deprivation stress to determine whether psychological stress during the early stage of life affected the development of brain function. We compared the electrophysiological properties of CA1 hippocampal pyramidal neurons and spatial memory in the Morris water maze test in the wild-type mouse and the homozygous mutant. In the non-stressed mouse, no significant differences in transsynaptic responses and synaptic plasticity or spatial memory were seen, suggesting that complexin II does not play a critical role in transmitter release or synaptic plasticity under these conditions. In contrast, under conditions of maternal deprivation stress, the knockout mouse showed a significant decrease in post-tetanic potentiation and LTP induction and a significant impairment in Morris water Maze test compared to the wild-type mouse, suggesting that complexin II plays a significant role in neurotransmitter release and synaptic plasticity under this pathological condition. Taken together, these results show that mice lacking complexin II are vulnerable to maternal deprivation stress, which raises the possibility that the complexin II gene may be a factor in the onset of schizophrenia.

Gene-environment interplay in schizopsychotic disorders

Genetic studies have sought to identify subtypes or endophenotypes of schizophrenia in an effort to improve the reliability of findings. A number of chromosomal regions or genes have now been shown to have had replicated linkage to schizophrenia susceptibility. Molecules involved in neurodevelopment or neurotransmitter function are coded by many of the genes that have been implicated in schizophrenia. Studies of neurotransmitter function have identified, among others, a possible role for GABA, glutamate and dopamine in animal models of schizophrenia. GABA neurons that co-express the calcium binding protein parvalbumin have been implicated as have glutamatergic metabotropic receptors and dopamine D3 receptors. Stress influences glutamate and dopamine providing another environmental factor that may interact with the influence of genes on neurotransmitter function. Neurotransmitter interactions include influences on signaling molecules and these too have been implicated in forms of learning thought to be affected in schizophrenia. Results continue to unravel the interplay of genes and environment in the etiology of schizophrenia and other psychotic disorders.

Gene-environment interplay in neurogenesis and neurodegeneration

Factors associated with predisposition and vulnerability to neurodegenerative disorders may be described usefully within the context of gene-environment interplay. There are many identified genetic determinants for so-called genetic disorders, and it is possible to duplicate many elements of recognized human neurodegenerative disorders in either knock-in or knock-out mice. However, there are similarly, many identifiable environmental influences on outcomes of the genetic defects; and the course of a progressive neurodegenerative disorder can be greatly modified by environmental elements. Constituent cellular defense mechanisms responsive to the challenge of increased reactive oxygen species represent only one crossroad whereby environment can influence genetic predisposition. In this paper we highlight some of the major neurodegenerative disorders and discuss possible links of gene-environment interplay. The process of adult neurogenesis in brain is also presented as an additional element that influences gene-environment interplay. And the so-called priming processes (i.e., production of receptor supersensitization by repeated drug dosing), is introduced as yet another process that influences how genes and environment ultimately and co-dependently govern behavioral ontogeny and outcome. In studies attributing the influence of genetic alteration on behavioral phenotypy, it is essential to carefully control environmental influences.