Alterations of White Matter Integrity Related to the Season of Birth in Schizophrenia: A DTI Study

Abstract

In schizophrenia there is a consistent epidemiological finding of a birth excess in winter and spring. Season of birth is thought to act as a proxy indicator for harmful environmental factors during foetal maturation. There is evidence that prenatal exposure to harmful environmental factors may trigger pathologic processes in the neurodevelopment, which subsequently increase the risk of schizophrenia. Since brain white matter alterations have repeatedly been found in schizophrenia, the objective of this study was to investigate whether white matter integrity was related to the season of birth in patients with schizophrenia. Thirty-four patients with schizophrenia and 33 healthy controls underwent diffusion tensor imaging. Differences in the fractional anisotropy maps of schizophrenia patients and healthy controls born in different seasons were analysed with tract-based spatial statistics. A significant main effect of season of birth and an interaction of group and season of birth showed that patients born in summer had significantly lower fractional anisotropy in widespread white matter regions than those born in the remainder of the year. Additionally, later age of schizophrenia onset was found in patients born in winter months. The current findings indicate a relationship of season of birth and white matter alterations in schizophrenia and consequently support the neurodevelopmental hypothesis of early pathological mechanisms in schizophrenia.

Myelin, myelin-related disorders, and psychosis

“…In both neuropathology and neuroimaging, it is uncertain whether white matter changes are an intrinsic component of schizophrenia or are the consequence of neuroleptic treatment, social deprivation, or other epiphenomena related to suffering from a chronic psychiatric disorder. A number of studies have suggested that the DTI abnormalities in schizophrenia are confounded by multiple factors, including the duration of illness and treatment with antipsychotic medications (Konopaske et al, 2006(Konopaske et al, , 2008, age (Kochunov et al, 2013a(Kochunov et al, , 2013bGiezendanner et al, 2013;Mandl et al, 2013), sex of the subjects (Savadjiev et al, 2014), and even heavy cigarette smoking (Cullen et al, 2012;Kochunov et al, 2013aKochunov et al, , 2013b.…”

Diffusion Tensor Imaging findings and their implications in schizophrenia

“…Several recent publications suggest that changes observed within white matter in schizophrenia might also be confounded by other factors, including age, life style, environmental factors, and so on. For example, Giezendanner et al [28] observed a relationship between season of birth and fractional anisotropy changes in schizophrenia (lower fractional anisotropy in those born in winter). For example, Kochunov et al [27 & ] reported accelerated fractional anisotropy decline with age in schizophrenia, but not in major depression.…”

The role of melatonin in the neurodevelopmental etiology of schizophrenia: A study in human olfactory neuronal precursors

“…Evidence obtained from animal models and epidemiological studies suggests that this disease involves an aberrant brain cortex and hippocampal formation caused by external insults, including maternal infections, vitamin deficiencies, or psychological stress . Importantly, alterations in the photoperiod during pregnancy have been correlated with the development of SZ when the child reaches adulthood …”