Environmental Factors In Schizophrenia Research Articles

Gene-Environment Interaction and Risk of Schizophrenia

Schizophrenia is a chronic mental disease that affects less than 1% of the population in the United States. In the introduction, the article provides a general overview of schizophrenia disorder, incorporating potential causal factors of schizophrenia in biological and environmental areas. It also demonstrated the individual and social impacts with present symptoms. Later in the mainbody sections, the article presents the general effects of gene-environment interaction on the risk of schizophrenia and the moderating role of environmental factors in schizophrenia by looking at the influences of childhood adversity in siblings with and without schizhophrenia, the role of family history and epigenetics, the effect of socioeconomic status (SES), and the relationship between stress and neurotransmitter activity in schizophrenia. On of the limitations of previous studies is that they were mainly conducted in adults who were diagnosed with schizophrenia already. Future studies should identify at-risk children and families to conduct longitudianl studies on this topic. This review can provide some guidance to the desgin of prevention and intervention programs at schools and communities for at-risk families.

Study protocol of the Berlin Research Initiative for Diagnostics, Genetics and Environmental Factors in Schizophrenia (BRIDGE-S)

BackgroundLarge-scale collaborative efforts in the field of psychiatric genetics have made substantial progress in unraveling the biological architecture of schizophrenia (SCZ). Although both genetic and environmental factors are known to play a role in schizophrenia etiology our mechanistic understanding of how they shape risk, resilience and disease trajectories remains limited.MethodsHere, we present the study protocol of the Berlin Research Initiative for Diagnostics, Genetic and Environmental Factors of Schizophrenia (BRIDGE-S), which aims to collect a densely phenotyped genetic cohort of 1,000 schizophrenia cases and 1,000 controls. The study’s main objectives are to build a resource for i) promoting genetic discoveries and ii) genotype–phenotype associations to infer specific disease subtypes, and iii) exploring gene-environment interactions using polyrisk models. All subjects provide a biological sample for genotyping and complete a core questionnaire capturing a variety of environmental exposures, demographic, psychological and health data. Approximately 50% of individuals in the sample will further undergo a comprehensive clinical and neurocognitive assessment.DiscussionWith BRIDGE-S we created a valuable database to study genomic and environmental contributions to schizophrenia risk, onset, and outcomes. Results of the BRIDGE-S study could yield insights into the etiological mechanisms of schizophrenia that could ultimately inform risk prediction, and early intervention and treatment strategies.

Hyperactivity of the default-mode network in first-episode, drug-naive schizophrenia at rest revealed by family-based case-control and traditional case-control designs.

Abnormal regional activity and functional connectivity of the default-mode network (DMN) have been reported in schizophrenia. However, previous studies may have been biased by unmatched case-control design. To limit such bias, the present study used both the family-based case-control design and the traditional case-control design to investigate abnormal regional activity of the DMN in patients with schizophrenia at rest.Twenty-eight first-episode, drug-naive patients with schizophrenia, 28 age-, sex-matched unaffected siblings of the patients (family-based controls, FBC), and 40 healthy controls (HC) underwent resting-state functional magnetic resonance imaging (fMRI) scans. The group-independent component analysis and fractional amplitude of low-frequency fluctuation (fALFF) methods were used to analyze the data.Patients with schizophrenia show increased fALFF in an overlapped region of the right superior medial prefrontal cortex (MPFC) relative to the FBC and the HC. Compared with the HC, the patients and the FBC exhibit increased fALFF in an overlapped region of the left posterior cingulate cortex/precuneus (PCC/PCu). Furthermore, the z values of the 2 overlapped regions can separate the patients from the FBC/HC, and separate the patients/FBC from the HC with relatively high sensitivity and specificity.Both the family-based case-control and traditional case-control designs reveal hyperactivity of the DMN in first-episode, drug-naive patients with paranoid schizophrenia, which highlights the importance of the DMN in the neurobiology of schizophrenia. Family-based case-control design can limit the confounding effects of environmental factors in schizophrenia. Combination of the family-based case-control and traditional case-control designs may be a viable option for the neuroimaging studies.

New evidences of gene and environment interactions affecting prenatal neurodevelopment in schizophrenia-spectrum disorders: A family dermatoglyphic study

BackgroundSeveral studies have reported an increase of dermatoglyphic anomalies in schizophrenic patients compared to controls. However, the recognition of specific dermatoglyphic variables related to this disorder and their genetic and/or environmental component are still controversial. MethodWe conducted a dermatoglyphic analysis in a new sample of 617 individuals: 205 patients with schizophrenia-spectrum disorders, 224 healthy first degree relatives and 188 healthy controls. The dermatoglyphic variables studied were: the total a–b ridge count (TABRC) and its fluctuating asymmetry (FAABRC), and the presence of ridge dissociations (RD) and abnormal palmar flexion creases (APFC). ResultsPatients, relatives and controls did not differ in TABRC. However, within the patients group those with a low birth weight or absence of psychiatric family history showed lower TABRC than the others. The frequency of ectodermic derivates abnormalities (RD and/or APFC) appeared to be higher in patients and relatives than in controls, while first degree relatives did not differ from patients. Males showed an increased rate of ectodermic derivates abnormalities compared to females in all groups and male patients also presented higher FAABRC than female patients. ConclusionsOur results suggest a different relative weight of genetic and environmental factors on each dermatoglyphic variable analyzed: i) TABRC may be a sensitive marker to environmental factors in schizophrenia, ii) ectodermal derivates abnormalities appear to be influenced by genetic risk factors, which could be involved both in the disrupted development of ectodermic derivates like dermatoglyphics and central nervous system and in the vulnerability for schizophrenia.

Environment and Schizophrenia: Environmental Factors in Schizophrenia: Childhood Trauma--A Critical Review

There is renewed interest in the relationship between early childhood trauma and risk of psychosis in adulthood. There are a large number of studies of psychiatric inpatients, and of outpatients in which a majority have a psychotic disorder, that suggest the prevalence of childhood trauma in these populations is high. However, these are generally small studies of diagnostically heterogeneous and chronic samples and, as such, can tell us very little about whether childhood trauma is of etiological importance in psychosis. A small number of recent population-based studies provide more robust evidence of an association, and there are now plausible biological mechanisms linking childhood trauma and psychosis. However, there remain a number of conceptual and methodological issues, which mean much more research is needed before firm conclusions can be drawn about whether childhood trauma is a cause of psychosis.

Environmental Factors in Schizophrenia: The Role of Migrant Studies

There is now compelling evidence that migrant groups in several countries have an elevated risk of developing schizophrenia and other psychotic disorders. Though the findings of earlier studies were greeted with skepticism, and ascribed by some to have methodological shortcomings and diagnostic biases, the more rigorous recent studies, from a variety of countries, have still found markedly increased incidence rates. While this phenomenon is an important health issue in its own right, understanding the reasons for the increased rates may provide valuable insights into the causes of schizophrenia and other psychotic disorders in general. The challenge for the next phase of studies is to identify the relevant risk factors and how they might interact to increase the risk of psychosis, both in migrant groups and in the general population.

Genetic and environmental factors in schizophrenia

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65-125 - Genetic and environmental factors in schizophrenia

65-125 - Genetic and environmental factors in schizophrenia

Public beliefs about causes and risk factors for depression and schizophrenia.

The objective of this study was to carry out a national survey to assess the Australian public's beliefs about causes and risk factors for mental disorders. A national household survey of 2,031 Australian adults was carried out. Half the respondents were presented with a vignette describing a person with major depression and the other half with a vignette describing schizophrenia. Respondents were asked to rate whether various factors are likely causes of problems such as that described in the vignette and to rate whether various groups are at higher or lower risk. For depression, social environmental factors were often seen as likely causes, which is consistent with the epidemiological evidence. However, genetic factors were considered as a likely cause by only half the population. For schizophrenia, social environmental factors were also often seen as causes, which is in contrast to the weak epidemiological evidence for such a role. Genetic factors attracted more support as a cause of schizophrenia than of depression. These findings point to areas where the mental health literacy of the population could be improved, particularly the over-emphasis on social environmental factors in schizophrenia. Of some concern was the belief of half the population that weakness of character is a likely cause of both depression and schizophrenia. This belief implies a negative evaluation of the sufferer as a person.

Sex differences in the interaction of disease-related and environmental factors in schizophrenia

Sex differences in the interaction of disease-related and environmental factors in schizophrenia

Investigating Putative Genetic and Environmental Forms of Schizophrenia: methods and findings

The existence of separate genetic and environmental forms of schizophrenia has been proposed as the basis for the probable heterogeneity in the etiology of schizophrenia. The rationale for a familial/sporadic strategy that compares positive versus negative family history cases and concordant versus discordant MZ twin pairs is discussed. A review of empirical findings from research utilizing the familial/sporadic strategy is presented. A number of methodological problems that have implications for the application of the strategy and the interpretation of results, such as misclassification, are discussed. It is concluded that the clustering of positive findings in certain domains suggests that this approach holds some promise for elucidating the role of genetic and environmental factors in schizophrenia.

Seasonality of birth in subtypes of chronic schizophrenia.

Several reports in the literature suggest that schizophrenic patients are disproportionately born during the colder months compared to the general population. In this study, we report differences in the seasonality of birth between the subtypes of chronic schizophrenia, particularly when gender is considered. Cold months' births (December to March) are most likely in nonparanoid females and paranoid males. Possible reasons for these differences are discussed in light of genetic and environmental factors in schizophrenia.

The natural history of schizophrenia in the long term.

It is well known that in some small European countries there exist especially favourable conditions for certain types of research which elsewhere meet enormous difficulties. This is exemplified in Denmark and other Scandinavian countries by the famous studies on the influence of genetic and environmental factors in schizophrenia, which were made possible by the exceptional availability of well organized national registers on twins, adoptees and psychotics.