Season of birth, gender and negative symptoms in schizophrenia

Early life climate and adulthood mental health: how birth seasonality influences depressive symptoms in adults

BACKGROUND

Early life in-utero can have long-term influence on the mental health status of individuals in adulthood, such as depression. Age, gender, socio-economic status, education, and geography are demographic factors shown to be particularly vulnerable towards the development of depressive symptoms. In addition, climate risks on depression include sunlight, rain, and temperature. However, whether climate factors in early life have a long-term influence on depression related to demographic vulnerability remains unknown. Here, the present study explored the association between birth seasonality and adulthood depressive symptoms.

METHODS

We employed data from the project of Chinese Labour-forces Dynamic Survey (CLDS) 2016, containing the epidemiological data of depressive symptoms with a probability proportional to size cluster and random cluster sampling method in 29 provinces of China. A final sample size of 16,185 participants was included. Birth seasonality included spring (March, April, and May), summer (June, July, and August), autumn (September, October, and November), and winter (December, January, and February).

RESULTS

We found that born in Autumn peaked lowest rate of having depressive symptoms (16.8%) and born in Summer (vs. Autumn) had a significant higher ratio (OR = 1.14, 95%CI = 1.02, 1.29) when controlling for demographic variables. In addition, demographic odds ratio of having depressive symptoms differed between people born in different seasons, particular for age and geography.

CONCLUSION

Our findings suggest that birth seasonality influences the sensitive link of depressive symptoms with age and geography. It implicates early life climate environment may play a role in the development of adulthood depressive symptoms.

Schizophrenia: a classic battle ground of nature versus nurture debate

Much has been learned about the etiology and pathogenesis of schizophrenia since the term was first used by Eugene Bleuler over a century ago to describe one of the most important forms of major mental illness to affect mankind. Both nature and nurture feature prominently in our understanding of the genesis of the overall risk of developing schizophrenia. We now have a firm grasp of the broad structure of the genetic architecture and several key environmental risk factors have been identified and delineated. However, much of the heritability of schizophrenia remains unexplained and the reported environmental risk factors do not explain all the variances not attributable to genetic risk factors. The biggest problem at present is that our understanding of the causal mechanisms involved is still in its infancy. In this review, we describe the extent and limits of our knowledge of the specific genetic/constitutional and non-genetic/environmental factors that contribute to the overall risk of schizophrenia. We suggest novel methods may be required to understand the almost certainly immensely complex multi-level causal mechanisms that contribute to the generation of the schizophrenia phenotype.

Birth Month and Course of Recurrent Depressive Disorders in a Polish Population

BACKGROUND The aim of this study was to determine whether the specific season of the year during which the first trimester of pregnancy takes place is significantly associated with the course (intensification and frequency of occurrence) of an episode of recurrent depressive disorder in adult life. MATERIAL AND METHODS We enrolled 184 patients treated for recurrent depressive disorders. RESULTS An analysis of the results obtained indicates that the greatest number of people suffering from a major depressive episode were born in the spring and summer (from April to September), meaning that the first trimester of pregnancy occurred between October and March. However, our results were not statistically significant, perhaps due to the small size of the examined group. CONCLUSIONS The results obtained indicate that birth month may be significantly associated with the course of recurrent depressive disorders. In patients from Central Europe, the first trimester of pregnancy falling in autumn and winter seems to be significant. These results need to be interpreted with caution due to the small size of the examined group.

Peaks of solar cycles affect the gender ratio

In this study, we report that the gender ratio (GR) at death [where GR=(N(males)/N(males)+N(females))] of those born (and likely conceived) in solar cycle peaks (about a 3-year period occurring on average every approximately 11 years), is inversely related to mean male age at death; e.g., the higher the GR(at death) the lower the mean lifespan, while the GR(at death) of those born in non-peak years has no relation to mean male lifespan. Although changes in the GR are small and may be of little clinical significance, the GR is a sensitive indicator of environmental effects, and therefore is pertinent to epigenetics. This paper supports the hypothesis that solar radiation, probably in the ultraviolet spectrum, by some manner interacts with chromosomal DNA (genes) and produces the genetic variety that not only fosters adaptation, but also produces the diseases that reduce lifespan. This paper also proposes that sunlight is more effective in modifying genomes at the time of conception than later in gestation or infancy. Referring to the work of others, this study also reveals that geographic latitude also affects the GR, suggesting that the variation in light is probably as important as the intensity of light in modifying genomes. This study finds that men sustain more genetic variation, producing 28% more disease than women, as well as a 2% decrease in GR from birth to death, and a shorter life (in Maine) by 7 years.

Psychosis and autism as diametrical disorders of the social brain

Autistic-spectrum conditions and psychotic-spectrum conditions (mainly schizophrenia, bipolar disorder, and major depression) represent two major suites of disorders of human cognition, affect, and behavior that involve altered development and function of the social brain. We describe evidence that a large set of phenotypic traits exhibit diametrically opposite phenotypes in autistic-spectrum versus psychotic-spectrum conditions, with a focus on schizophrenia. This suite of traits is inter-correlated, in that autism involves a general pattern of constrained overgrowth, whereas schizophrenia involves undergrowth. These disorders also exhibit diametric patterns for traits related to social brain development, including aspects of gaze, agency, social cognition, local versus global processing, language, and behavior. Social cognition is thus underdeveloped in autistic-spectrum conditions and hyper-developed on the psychotic spectrum.;>We propose and evaluate a novel hypothesis that may help to explain these diametric phenotypes: that the development of these two sets of conditions is mediated in part by alterations of genomic imprinting. Evidence regarding the genetic, physiological, neurological, and psychological underpinnings of psychotic-spectrum conditions supports the hypothesis that the etiologies of these conditions involve biases towards increased relative effects from imprinted genes with maternal expression, which engender a general pattern of undergrowth. By contrast, autistic-spectrum conditions appear to involve increased relative bias towards effects of paternally expressed genes, which mediate overgrowth. This hypothesis provides a simple yet comprehensive theory, grounded in evolutionary biology and genetics, for understanding the causes and phenotypes of autistic-spectrum and psychotic-spectrum conditions.

Excess in the spring and deficit in the autumn in birth rates of male schizophrenic patients in Italy: potential role of perinatal risk factors

OBJECTIVE

The aim of this study was to evaluate whether there were different seasonal variations of births in an Italian population of patients with schizophrenia, with other psychotic disorders, and with personality disorders than in the general population.

METHODS

Birth dates of 1270 patients admitted to one university psychiatric unit in Rome between 1990 and 2003, with a diagnosis of schizophrenia, other psychotic disorder (OPD) and personality disorder/cluster A (PD) were analyzed according to seasonal variation.

RESULTS

A significant excess of births in spring (with a peak in May) and a deficit in autumn (with a trough in October) was found in the sample of male schizophrenics (n = 506). No statistically significant variations were found in either the sample of female schizophrenics (n = 88) or in the combined sample with OPD and PD (n = 676).

CONCLUSIONS

The findings serve to strengthen the existing hypotheses that schizophrenia is related to environmental factors acting on the development of the central nervous system intrauterinely.

Season of birth, age and negative symptoms in a Xhosa schizophrenia sample from the Southern Hemisphere

OBJECTIVES

Seasonality of birth, more specifically winter/spring births, has been implicated as a risk factor for the development of schizophrenia. The primary aim of this study was to determine whether schizophrenia patients of Xhosa ethnicity born in autumn/winter have different symptom profiles to those born in spring/summer. The secondary aim was to determine whether the autumn/winter and spring/summer birth rates for schizophrenia patients of Xhosa ethnicity were similar to that of the general Xhosa population.

METHOD

Individuals with a diagnosis of schizophrenia, born in the Western and Eastern Cape Provinces of South Africa (n = 386), were categorized as autumn/winter-born (March to August) patients or summer/spring-born (September to February) patients. Negative global scores of the schedules for the assessment of negative symptoms were categorized as normal (rating of 0 and 1) or positive (rating of 2 to 5).

RESULTS

Patients born in autumn/winter were more likely to have avolition/apathy than those born in summer/spring. The results also showed that the age of the patients played a significant role in modifying the effect of the season of birth on symptoms of schizophrenia. Especially older people (more than 30 years old) born in autumn/winter had a higher incidence of avolition/apathy than those born in summer/spring (p = 0.026). Furthermore, in the relationship of birth season and avolition/apathy, the marital status of the patient was a significant independent explanatory variable, while gender was not. The study also showed a spring excess of 4% in birth rate compared with the general Xhosa population.

CONCLUSION

The results from our study support the existence of a seasonal birth pattern in an African schizophrenia population and suggest that avolition/apathy may underpin this seasonal pattern.

Clinical characteristics and risk factors for Kraepelinian subtype of schizophrenia: replication of previous findings and relation to summer birth

The aims of the study were: (1) to replicate findings that patients with Kraepelinian schizophrenia constitute a distinct subgroup and (2) to examine the relationship between season of birth and the Kraepelinian subtype. Thirty-one Kraepelinian patients, defined on the basis of a longitudinal criterion--at least 5 years of continuous and complete dependence on others to maintain the basic necessities of life, including food, clothing and shelter--were compared with 279 non-Kraepelinian schizophrenic patients. All patients met ICD-10 criteria for schizophrenia and were evaluated with the Positive and Negative Syndrome Scale. Kraepelinian schizophrenic patients had more negative symptoms and were more disorganized than non-Kraepelinian patients. Positive and anxious-depressive symptoms did not differ between the two groups. Among Kraepelinian patients, there was an excess number of births in the month of July. These findings are consistent with previous reports that Kraepelinian patients could have a disease with an etiopathophysiology separate from that of other schizophrenic patients.