Correlations between obstetric complications and neurological soft signs in Tunisian patients with schizophrenia

Are neurological soft signs pre-existing markers in individuals with an at-risk mental state for psychosis?

Neurological soft signs (NSS) are more common in schizophrenic psychoses and in genetically high-risk individuals than in healthy controls. But nothing is known so far regarding individuals with a clinical at-risk mental state (ARMS). The goals of our study therefore were (a) to compare the NSS frequency in ARMS individuals to that of first-episode psychosis (FEP) patients and (b) to test whether NSS could predict the transition to psychosis. Neurological soft signs were assessed using a shortened version of the Neurological Evaluation Scale (NES). Fifty-three ARMS individuals (16 with later transition to psychosis=ARMS-T, and 37 without transition=ARMS-NT) and 27 FEP patients were recruited through the Basel Early Detection Clinic FePsy. Of the FEP patients 37% showed NSS. We found no significant differences between FEP and ARMS-T patients or between ARMS-NT and ARMS-T. Our findings of NSS being present already before transition to psychosis to the same extent as after transition provide further support to the neurodevelopmental hypothesis of schizophrenic psychoses. Furthermore, our findings might indicate that ARMS-NT individuals also suffer from some sort of neurodevelopmental abnormalities.

Precursors of cognitive impairments in psychotic disorders: a population-based study

Cognitive deficits have been found to be more prevalent in psychotic than in other disorders. Longitudinal research has shown that these deficits were generally already existent before onset of illness and are therefore not necessarily attributable to neurodegenerative processes. This study investigated whether both low IQ and markers of premorbid cognitive dysfunction independently contribute to an increased risk for psychoses. In a cross-sectional study about 50,000 young Swiss males completed a survey of intellectual problems in childhood/adolescence and other vulnerability factors during military call-up in 2005/2006. Subsequently, military IQ assessments were carried out on the entire sample. Diagnostic assessments were conducted according to International Classification of Diseases-10th edition (ICD-10). Low, especially performance, IQ was highly associated with an increased risk for psychotic disorders after adjusting for preexisting cognitive deficits and covariates, while in other disorders this association was less marked. Furthermore, preexisting intellectual problems emerged as important risk factors for psychoses. Our results confirm the importance of low IQ as characteristic of psychoses. Although premorbid intellectual deficits are common in people who go on to develop psychosis, neurodegenerative disease processes may also precipitate further declines in fluid cognitive functions. Assessment of cognitive functioning should be taken into account in early detection of psychoses.

Oligodendroglial alterations and the role of microglia in white matter injury: relevance to schizophrenia

Schizophrenia is a chronic and debilitating mental illness characterized by a broad range of abnormal behaviors, including delusions and hallucinations, impaired cognitive function, as well as mood disturbances and social withdrawal. Due to the heterogeneous nature of the disease, the causes of schizophrenia are very complex; its etiology is believed to involve multiple brain regions and the connections between them, and includes alterations in both gray and white matter regions. The onset of symptoms varies with age and severity, and there is some debate over a degenerative or developmental etiology. Longitudinal magnetic resonance imaging studies have detected progressive gray matter loss in the first years of disease, suggesting neurodegeneration; but there is also increasing recognition of a temporal association between clinical complications at birth and disease onset that supports a neurodevelopmental origin. Presently, neuronal abnormalities in schizophrenia are better understood than alterations in myelin-producing cells of the brain, the oligodendrocytes, which are the predominant constituents of white matter structures. Proper white matter development and its structural integrity critically impacts brain connectivity, which affects sensorimotor coordination and cognitive ability. Evidence of defective white matter growth and compromised white matter integrity has been found in individuals at high risk of psychosis, and decreased numbers of mature oligodendrocytes are detected in schizophrenia patients. Inflammatory markers, including proinflammatory cytokines and chemokines, are also associated with psychosis. A relationship between risk of psychosis, white matter defects and prenatal inflammation is being established. Animal models of perinatal brain injury are successful in producing white matter damage in the brain, typified by hypomyelination and/or dysmyelination, impaired motor coordination and prepulse inhibition of the acoustic startle reflex, recapitulating structural and functional characteristics observed in schizophrenia. In addition, elevated expression of inflammation-related genes in brain tissue and increased production of cytokines by blood cells from patients with schizophrenia indicate immunological dysfunction and abnormal inflammatory responses, which are also important underlying features in experimental models. Microglia, resident immune defenders of the central nervous system, play important roles in the development and protection of neural cells, but can contribute to injury under pathological conditions. This article discusses oligodendroglial changes in schizophrenia and focuses on microglial activity in the context of the disease, in neonatal brain injury and in various experimental models of white matter damage. These include disorders associated with premature birth, and animal models of perinatal bacterial and viral infection, oxygen deprivation (hypoxia) and excess (hyperoxia), and elevated systemic proinflammatory cytokine levels. We briefly review the effects of treatment with antipsychotic and anti-inflammatory agents in models of perinatal brain injury, and comment on the therapeutic potential of these strategies. By understanding the neurobiological basis of oligodendroglial abnormalities in schizophrenia, it is hoped that patients will benefit from the availability of targeted and more efficacious treatment options.

Obstetric complications and neurological soft signs in male patients with schizophrenia

Bersani G, Clemente R, Gherardelli S, Bersani FS, Manuali G. Obstetric complications and neurological soft signs in male patients with schizophrenia.

Objective: The study investigated the relationship between neurological soft signs (NSS) and obstetric complications (OCs) in patients with schizophrenia.

Methods: Sixty-three male patients with schizophrenia were divided into two subgroups, based on the OCs presence or absence, which were compared in relation to NSS prevalence. After that, a Person's correlation test was performed to explore the correlation between NSS and OCs severity.

Results: The subgroup with OCs showed more NSS, but there were not significant correlations between NSS and OCs severity.

Conclusions: It seems that any OC, without distinction in typology and severity, could unspecifically impair the neurodevelopment and inducing NSS expression. Our findings confirm the hypothesis that neurodevelopment alterations, such as those probably induced by OCs, can contribute to a premorbid brain dysfunctional state expressed by NSS.