Development and initial validation of a multivariable predictive Early Adversity Scale for Schizophrenia (EAS-Sz) using register data to quantify environmental risk for adult schizophrenia diagnosis after childhood exposure to adversity.

BACKGROUND: Additional to a child's genetic inheritance, environmental exposures are associated with schizophrenia. Many are broadly described as childhood adversity; modelling the combined impact of these is complex. We aimed to develop and validate a scale on childhood adversity, independent of genetic and other environmental liabilities, for use in schizophrenia risk analysis models, using data from cross-linked electronic health and social services registers. METHOD: A cohort of N = 428 970 Western Australian children born 1980-2001 was partitioned into three samples: scale development sample (N = 171 588), and two scale validation samples (each N = 128 691). Measures of adversity were defined before a child's 10th birthday from five domains: discontinuity in parenting, family functioning, family structure, area-level socioeconomic/demographic environment and family-level sociodemographic status. Using Cox proportional hazards modelling of follow-up time from 10th birthday to schizophrenia diagnosis or censorship, weighted combinations of measures were firstly developed into scales for each domain, then combined into a final global scale. Discrimination and calibration performance were validated using Harrell's C and graphical assessment respectively. RESULTS: A weighted combination of 42 measures of childhood adversity was derived from the development sample. Independent application to identical measures in validation samples produced Harrell's Concordance statistics of 0.656 and 0.624. Average predicted time to diagnosis curves corresponded with 95% CI limits of observed Kaplan-Meier curves in five prognostic categories. CONCLUSIONS: Our Early Adversity Scale for Schizophrenia (EAS-Sz), the first using routinely collected register data, predicts schizophrenia diagnosis above chance, and has potential to help untangle contributions of genetic and environmental liability to schizophrenia risk.

Patterns of psychiatric admission in Australian pregnant and childbearing women.

PURPOSE: The early postnatal period is a time of increased risk for psychiatric admission. However, there is scope to further examine if this increase in risk extends to the entire perinatal period (pregnancy and first postnatal year), and how it compares to admission outside of the perinatal period. METHODS: Data were linked across birth and hospital admission registers from July 2000 to December 2009. The study cohort, consisting of all pregnant and childbearing women with a psychiatric history, was divided into two groups: case women (at least one perinatal principal psychiatric admission in the study period) (38%) and comparison women (no perinatal principal psychiatric admissions) (62%). Outcomes were admission rate and length of stay adjusted for diagnosis, socio-demographic factors and timing of admission. RESULTS: Antenatal and postnatal admissions rates were both higher than non-perinatal admission rates for case women for all diagnoses. There was little evidence that women with perinatal admissions were at an increased risk of admissions at other times. Socially disadvantaged women had significantly fewer and shorter admissions than their respective counterparts. CONCLUSIONS: The entire perinatal period is a time of increased risk for admission across the range of psychiatric disorders, compared to other times in a woman's childbearing years. Reduced admission rate and length of stay for socially disadvantaged women suggest lack of equity of access highlighting the importance of national perinatal mental health policy initiatives inclusive of disadvantaged groups.

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

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.

The National Perinatal Depression Initiative: An evaluation of access to general practitioners, psychologists and psychiatrists through the Medicare Benefits Schedule.

OBJECTIVE: To evaluate the impact of the National Perinatal Depression Initiative on access to Medicare services for women at risk of perinatal mental illness. METHOD: Retrospective cohort study using difference-in-difference analytical methods to quantify the impact of the National Perinatal Depression Initiative policies on Medicare Benefits Schedule mental health usage by Australian women giving birth between 2006 and 2010. A random sample of women of reproductive age enrolled in Medicare who had not given birth where used as controls. The main outcome measures were the proportions of women giving birth each month who accessed a Medicare Benefits Schedule mental health items during the perinatal period (pregnancy through to the end of the first postnatal year) before and after the introduction of the National Perinatal Depression Initiative. RESULTS: The proportion of women giving birth who accessed at least one mental health item during the perinatal period increased from 88 to 141 per 1000 between 2007 and 2010. The difference-in-difference analysis showed that while there was an overall increase in Medicare Benefits Schedule mental health item access as a result of the National Perinatal Depression Initiative, this did not reach statistical significance. However, the National Perinatal Depression Initiative was found to significantly increase access in subpopulations of women, particularly those aged under 25 and over 34 years living in major cities. CONCLUSION: In the 2 years following its introduction, the National Perinatal Depression Initiative was found to have increased access to Medicare funded mental health services in particular groups of women. However, an overall increase across all groups did not reach statistical significance. Further studies are needed to assess the impact of the National Perinatal Depression Initiative on women during childbearing years, including access to tertiary care, the cost-effectiveness of the initiative, and mental health outcomes. It is recommended that new mental health policy initiatives incorporate a planned strategic approach to evaluation, which includes sufficient follow-up to assess the impact of public health strategies.

Intellectual disability and other neuropsychiatric outcomes in high-risk children of mothers with schizophrenia, bipolar disorder and unipolar major depression.

BACKGROUND: Recent evidence points to partially shared genetics of neuropsychiatric disorders. AIMS: We examined risk of intellectual disability and other neuropsychiatric outcomes in 3174 children of mothers with schizophrenia, bipolar disorder or unipolar major depression compared with 3129 children of unaffected mothers. METHOD: We used record linkage across Western Australian population-based registers. The contribution of obstetric factors to risk of intellectual disability was assessed. RESULTS: Children were at significantly increased risk of intellectual disability with odds ratios (ORs) of 3.2 (95% CI 1.8-5.7), 3.1 (95% CI 1.9-4.9) and 2.9 (95% CI 1.8-4.7) in the maternal schizophrenia, bipolar disorder and unipolar depression groups respectively. Multivariate analysis suggests familial and obstetric factors may contribute independently to the risk. Although summated labour/delivery complications (OR = 1.4, 95% CI 1.0-2.0) just failed to reach significance, neonatal encephalopathy (OR = 7.7, 95% CI 3.0-20.2) and fetal distress (OR = 1.8, 95% CI 1.1-2.7) were independent significant predictors. Rates of rare syndromes in children of mothers with mental disorder were well above population rates. Risk of pervasive developmental disorders, including autism, was significantly elevated for children of mothers with bipolar disorder. Risk of epilepsy was doubled for children of mothers with unipolar depression. CONCLUSIONS: Our findings provide epidemiological support for clustering of neuropsychiatric disorders. Further larger epidemiological studies are warranted.

Recorded pregnancy histories of the mothers of singletons and the mothers of twins: a longitudinal comparison.

A population-based record linkage case cohort of 239,995 births, to 119,214 women, born in Western Australia from 1980 to 2001 inclusive, was used to measure the recording of selected indicators of maternal health (current and prior) during pregnancy. We compared records of women with singleton pregnancies with that in twin pregnancies Mothers of first- and second-born singletons (n = 117,647) were compared with women with a first-born singleton followed by twins (n = 1,567). Binary indicators were used to calculate population prevalence of medical conditions, pregnancy complications and birth outcomes. Infant outcomes included stillbirth, low birthweight, preterm birth and birth defects. Women with twins were significantly older and taller, with similar rates of medical conditions and pregnancy complications during first singleton pregnancies compared with women with two consecutive singletons. However, during their second pregnancy, women with twins had significantly higher rates of essential hypertension, pre-eclampsia, threatened abortion, premature rupture of the membranes and ante partum hemorrhage with abruption than women with singletons. For both groups, maternal conditions in the first pregnancy were underreported in the second pregnancy, including diabetes, epilepsy, asthma, chronic renal dysfunction and essential hypertension. At the second birth, twins were 3 times more likely to be stillborn, 17 times more likely to be low birthweight and 4 times more likely to be delivered preterm compared with singletons. This research demonstrates the importance for epidemiologists and others, of having access to a complete maternal medical history for analyses of risks associated with maternal, infant and childhood morbidity.

Parsing components of risk of premature mortality in the children of mothers with severe mental illness.

INTRODUCTION: Children of mothers with severe mental illness are at increased risk of premature death including in infancy and early childhood. Importantly, these children are also more likely to be exposed to adverse socio-demographic risk factors and serious obstetric complications which, of themselves, may increase risk for childhood mortality. We examined mortality outcome at different ages up to 5 years taking account of these risks. METHOD: We used linked data across Western Australian whole-population psychiatric, inpatient, death, and midwives' registers to identify 15,486 births to mothers with severe mental illness and 452,459 births to mothers with no mental illness. Multivariable models were adjusted for exposure to adverse socio-demographic risk factors and serious obstetric complications. RESULTS: Overall risk of premature death was increased amongst children of mothers with severe mental illness (2.3%, 354 deaths) compared with children of mothers with no mental illness (1.4%, 6523 deaths); the same was true for specific risk of stillbirth, neonatal, post­neonatal and early childhood deaths. Risk was substantially attenuated after adjustment for adverse socio-demographic exposures, and further still after adjustment for exposure to serious obstetric complications. We observed no effects for the timing of maternal illness diagnosis. CONCLUSIONS: To minimise the risk of premature mortality in the children of mothers with severe mental illness, priority should be given to the prompt diagnosis of maternal mental illness with targeted delivery of high quality antenatal and psychiatric care, as well as social and structural supports for affected families that continue after birth.

How couples cope with the death of a twin or higher order multiple.

Fifty-two Australian couples who had experienced the death of at least one member of a multiple birth (twin or higher order), with at least one survivor of that birth, were interviewed about their experiences at the time of the death, and since. This study compared parents' coping after the twins' deaths using the Beck Depression Inventory II, Perinatal Grief Scale, and unstructured interviews with some structured queries. Parents provided information on the influence of family, community and medical staff. According to retrospective reports, mothers experienced significantly more depression and grief than fathers at the time of loss. Both parents found the death of their twins grievous, but fathers, unlike mothers, were not encouraged to express their emotions. Although parents generally agreed about what helped them cope, fathers believed that they should be able to cope regardless of their grief. The strength of parents' spiritual beliefs had increased significantly since their loss, and there was some evidence that depressed and grieving mothers turned to spiritual support. Parents whose children died earlier reported levels of depression similar to those reported by parents whose children died later. To date, this is the largest study of grief in couples who have experienced the death of a twin and who have a surviving twin or higher order multiple.

Intellectual Disability and Psychotic Disorders in Children: Association With Maternal Severe Mental Illness and Exposure to Obstetric Complications in a Whole-Population Cohort.

OBJECTIVE: Children of mothers with severe mental illness are at significantly increased risk of developing intellectual disability. Obstetric complications are also implicated in the risk for intellectual disability. Moreover, children of mothers with severe mental illness are more likely to be exposed to obstetric complications. The purpose of this study was to examine the independent and joint contributions of familial severe mental illness and obstetric complications to the risk of intellectual disability. METHOD: Record linkage across Western Australian whole-population psychiatric, inpatient, birth, and midwives' registers identified 15,351 children born between 1980 and 2001 to mothers with severe mental illness and 449,229 children born to mothers with no mental illness. Multivariable models were adjusted for paternal psychiatric status, parental intellectual disability, and other family and sociodemographic covariates. RESULTS: The risk of intellectual disability was increased among children of mothers with severe mental illness compared with children of unaffected mothers. The impact varied across maternal diagnostic groups. For children of mothers with schizophrenia, the unadjusted odds ratio was 3.8 (95% CI=3.0, 4.9) and remained significant after simultaneous adjustment for exposure to obstetric complications and other covariates (odds ratio=1.7, 95% CI=1.3, 2.3). The odds ratio for exposure to obstetric complications also remained significant after adjustment (odds ratio=1.7, 95% CI=1.6, 1.8). For intellectual disability of a genetic basis, the adjusted odds ratio for maternal schizophrenia was elevated but not statistically significant. Among children with intellectual disability, 4.2% later developed a psychotic disorder, compared with 1.1% of children without intellectual disability. CONCLUSIONS: Maternal severe mental illness and exposure to obstetric complications contribute separately to the risk of intellectual disability, suggesting potentially different causal pathways.

Mental health consultations in the perinatal period: a cost-analysis of Medicare services provided to women during a period of intense mental health reform in Australia.

Objective To quantify total provider fees, benefits paid by the Australian Government and out-of-pocket patients' costs of mental health Medicare Benefits Schedule (MBS) consultations provided to women in the perinatal period (pregnancy to end of the first postnatal year). Method A retrospective study of MBS utilisation and costs (in 2011-12 A$) for women giving birth between 2006 and 2010 by state, provider-type, and geographic remoteness was undertaken. Results The cost of mental health consultations during the perinatal period was A$17.5million for women giving birth in 2007, rising to A$29million in 2010. Almost 9% of women giving birth in 2007 had a mental health consultation compared with more than 14% in 2010. An increase in women accessing consultations, along with an increase in the average number of consultations received, were the main drivers of the increased cost, with costs per service remaining stable. There was a shift to non-specialist care and bulk billing rates increased from 44% to 52% over the study period. In 2010, the average total cost (provider fees) per woman accessing mental health consultations during the perinatal period was A$689, and the average cost per service was A$133. Compared with women residing in regional and remote areas, women residing in major cities where more likely to access consultations, and these were more likely to be with a psychiatrist rather than an allied health professional or general practitioner. Conclusion Increased access to mental health consultations has coincided with the introduction of recent mental health initiatives, however disparities exist based on geographic location. This detailed cost analysis identifies inequities of access to perinatal mental health services in regional and remote areas and provides important data for economic and policy analysis of future mental health initiatives. What is known about the topic? The mental healthcare landscape in Australia has changed significantly over the last decade, with the introduction of numerous policies aimed at prevention, screening and improving access to treatment. Several of these policies have been aimed at perinatal depression, which affects 15% of women giving birth. What does this paper add? This is the first population-based, cost analysis of mental health consultations during the perinatal period (pregnancy to end of the first postnatal year) in Australia. Almost 9% of women giving birth in 2007 had a mental health consultation funded though the MBS, compared with more than 14% in 2010. Over the same period there was a shift from psychiatric consultations to allied health and primary care consultations. In 2010, the total cost (provider fee) of these consultations was A$29million, equating to an average cost per woman of A$689 and A$133 per service. Despite the changing policy environment, significant disparities exist in access to care according to geographic remoteness. What are the implications for practitioners? Recent policy initiatives have resulted in increasing access to mental health consultations for women around the time of childbirth. However, policies are needed that target women outside of major cities. Furthermore, evidence is needed on whether the increase in access has resulted in improved mental health outcomes for women at this vulnerable time. The cost data provided by this study are unique and will inform future mental health policy development and health economic evaluations.

Population based ascertainment of twins and their siblings, born in Western Australia 1980 to 1992, through the construction and validation of a maternally linked database of siblings.

This paper describes the creation of a unique maternal identifier for use in the investigation of perinatal, postneonatal and child outcomes in relation to maternal characteristics. All Midwives' records of Western Australian (WA) births were routinely linked to registrations of births and deaths for infants born from 1980 to 1992 inclusive, then linked to WA hospital discharge data and to registries of birth defects and cerebral palsy to create a longitudinal health record for each infant. However, since each birth to a woman was recorded as a separate event, there was no way to identify siblings. Probabilistic record linkage, based on information about the mother, was used for this task. Logical inconsistencies within the data were used to test the validity of the linkages between birth records attributed to each mother. Information about the mother from other epidemiological studies and data abstracted from hospital case notes was also used to validate sibships. Linkage of the records of 310,255 births in WA during that period resulted in the formation of 181,133 sibships of one or more children. Pooling the results of all of the validation methods gave an error of 0.9%. Linkage identified 3678 sibships containing multiple births, and 305 sets of maternal twins. Ascertainment of twins and their siblings for an ongoing twin register, the WA Twin Child Health (WATCH) study, was a natural consequence of this process.

The Western Australian Register of Childhood Multiples: effects of questionnaire design and follow-up protocol on response rates and representativeness.

Twin registers have been established worldwide to study the roles of genes and the environment in health and behaviour. While questionnaire surveys are thought to be the most cost-effective way of collecting large amounts of data, low response rates can result in response bias. Many different strategies have been proposed to maximise response rates. A register of all multiple births occurring in Western Australia (WA) from 1980 onwards has been established using probabilistic record linkage techniques. Families who had not experienced the death of one or more of their multiples were invited to participate in the Western Australian Twin Child Health (WATCH) study, which studied the genetic and environmental determinants of childhood asthma and atopy. Several questionnaire designs and follow-up methods were assessed. We have shown that it was feasible to use a population-based register of multiple births to contact families for a questionnaire study. Questionnaire length, mode of follow-up, the number of responses required and the of participants all seemed to affect response.