No Evidence of Association between Childhood Urban Environment and Cortical Thinning in Psychotic Disorder.

Aleida Frissen,Ritsaert Lieverse,Machteld Marcelis,Ed Gronenschild,Jim van Os,Petra Habets,Takanori Hashimoto

doi:10.1371/journal.pone.0166651

Aleida Frissen, Ritsaert Lieverse + Show 5 more

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https://doi.org/10.1371/journal.pone.0166651

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Abstract

BackgroundThe alterations in cortical morphology, such as cortical thinning, observed in psychotic disorder, may be the outcome of interacting genetic and environmental effects. It has been suggested that urban upbringing may represent a proxy environmental effect impacting cortical thickness (CT). Therefore, the current study examined whether the association between group as a proxy genetic variable (patients with psychotic disorder [high genetic risk], healthy siblings of patients [intermediate risk] and healthy control subjects [average risk]) and CT was conditional on different levels of the childhood urban environment and whether this was sex-dependent.MethodsT1-weighted MRI scans were acquired from 89 patients with a psychotic disorder, 95 non-psychotic siblings of patients with psychotic disorder and 87 healthy control subjects. Freesurfer software was used to measure CT. Developmental urban exposure was classified as low, medium, and high, reflecting the population density and the number of moves between birth and the 15th birthday, using data from the Dutch Central Bureau of Statistics and the equivalent database in Belgium. Multilevel regression analyses were used to examine the association between group, sex, and urban upbringing (as well as their interactions) and cortical CT as the dependent variable.ResultsCT was significantly smaller in the patient group compared to the controls (B = -0.043, p <0.001), but not in the siblings compared to the controls (B = -0.013, p = 0.31). There was no main effect of developmental urbanicity on CT (B = 0.001, p = 0.91). Neither the three-way group × urbanicity × sex interaction (χ2 = 3.73, p = 0.16), nor the two-way group × urbanicity interaction was significant (χ2 = 0.51, p = 0.77).ConclusionThe negative association between (familial risk for) psychotic disorder and CT was not moderated by developmental urbanicity, suggesting that reduced CT is not the outcome of familial sensitivity to the proxy environmental factor ‘urban upbringing’.

Highlights

Childhood urban environment is one of the environmental risk factors for psychotic disorder
The current study examined whether the association between group as a proxy genetic variable and cortical thickness (CT) was conditional on different levels of the childhood urban environment and whether this was sex-dependent
The negative association between psychotic disorder and CT was not moderated by developmental urbanicity, suggesting that reduced CT is not the outcome of familial sensitivity to the proxy environmental factor ‘urban upbringing’

Summary

Introduction

Childhood urban environment is one of the (proxy) environmental risk factors for psychotic disorder. The vulnerable period of impact is specific to childhood and adolescence [8, 9] and the effect of the urban environment may be conditional on the genetic risk for psychotic disorder [10,11,12]. The current study examined whether the association between group as a proxy genetic variable (patients with psychotic disorder [high genetic risk], healthy siblings of patients [intermediate risk] and healthy control subjects [average risk]) and CT was conditional on different levels of the childhood urban environment and whether this was sex-dependent

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Results

Conclusion