Are familial liability for schizophrenia and obstetric complications independently associated with risk of psychotic illness, after adjusting for other environmental stressors in childhood?

Abstract

Objective: The interplay between genetic and environmental factors on risk for psychotic illness remains poorly understood. The aim of this study was to estimate independent and combined effects of familial liability for schizophrenia and exposure to obstetric complications on risk for developing psychotic illness, covarying with exposure to other environmental stressors. Methods: This whole-population birth cohort study used record linkage across Western Australian statewide data collections (midwives, psychiatric, hospital admissions, child protection, mortality) to identify liveborn offspring ( n = 1046) born 1980–1995 to mothers with schizophrenia, comparing them to offspring of mothers with no recorded psychiatric history ( n = 298,370). Results: Both maternal schizophrenia and pregnancy complications were each significantly associated with psychotic illness in offspring, with no interaction. Non-obstetric environmental stressors significantly associated with psychotic illness in offspring included the following: being Indigenous; having a mother who was not in a partnered relationship; episodes of disrupted parenting due to hospitalisation of mother, father or child; abuse in childhood; and living in areas of greatest socioeconomic disadvantage and with elevated rates of violent crime. Adjustment for these other environmental stressors reduced the hazard ratio for maternal schizophrenia substantially (from hazard ratio: 5.7, confidence interval: 4.5–7.2 to hazard ratio: 3.5, confidence interval: 2.8–4.4), but not the estimate for pregnancy complications (hazard ratio: 1.1, confidence interval: 1.0–1.2). The population attributable fraction for maternal schizophrenia was 1.4 and for pregnancy complications was 2.1. Conclusion: Our finding of a substantial decrease in risk of psychotic illness associated with familial liability for psychosis following adjustment for other environmental stressors highlights potentially modifiable risk factors on the trajectory to psychotic illness and suggests that interventions that reduce or manage exposure to these risks may be protective, despite a genetic liability.

Factors that contribute to urban–rural gradients in risk of schizophrenia: Comparing Danish and Western Australian registers

“…Indeed, the expected urbanrural pattern was only confirmed for England and the Netherlands, while no significant association was found for Spain or France, and an inverse (urban protective) finding was identified in Italy. A study based in Western Australia also failed to confirm the expected urban-rural gradient, showing a gradient in the opposite direction which disappeared after adjustment for a range of covariates (Morgan et al, 2019).…”

Leveraging Administrative Data to Better Understand and Address Child Maltreatment: A Scoping Review of Data Linkage Studies

“…21 years), outcomes studied included depression and anxiety disorders ( Dahl et al, 2017 ; Scott et al, 2012 ), attentional problems ( Boyd et al, 2019 ), internalising and externalising behaviours ( Kisely et al, 2018 ; Scott et al, 2010 ), post-traumatic stress disorder ( Scott et al, 2010 ), alcohol or substance use disorders ( Kisely, Mills, et al, 2020 ; Scott et al, 2010 , 2012 ), and low quality of life ( Abajobir, Kisely, Williams, Strathearn, Clavarino, & Najman, 2017 ). In later adulthood, outcomes studied included schizophrenia and psychotic disorders ( Cutajar et al, 2010a , 2010b ; Morgan et al, 2019 ; Spataro et al, 2004 ).…”

Multigenerational Health Research using Population-Based Linked Databases: An International Review

“…Three European sites (Denmark, Norway, Sweden) and three non-European sites (Canadian province of Manitoba, Taiwan, Australian state of Western Australia) have the unique capability to define familial relationships and objectively-measured health histories from administrative and healthcare electronic records. Studies from these sites have made important contributions to understanding associations between familial health histories and individual outcomes for a broad range of health conditions or life events [6][7][8][9][10][11][12][13][14].…”