Background A persistent debate in psychiatry concerns whether schizophrenia and bipolar disorder are the clinical realizations of discrete versus shared etiological processes. Methods We linked the Multi-Generation Register, containing information about children and their parents of all Swedes, and the Hospital Discharge Register, covering all public psychiatric inpatient hospitalizations in Sweden. We identified 9,009,202 unique individuals in more than 2 million nuclear families. Risks for schizophrenia, bipolar disorder and their co-morbidity were calculated for biological and adoptive parents, offspring, full siblings and half-siblings of probands with the diseases. A multivariate generalized linear mixed model was used to estimate genetic and environmental contributions to liability for schizophrenia, bipolar disorder, and their co-morbidity. Findings There were increased risks of both schizophrenia and bipolar disorder to first degree relatives of probands with either disorder. Half-sibs had a significantly increased risk, albeit substantially lower than the full-siblings. When relatives of probands with bipolar disorder were analysed, increased risks for schizophrenia were present for all relationships, including offspring adopted away. Heritability for schizophrenia was 64% and for bipolar disorder 59%. Shared environmental effects were small but significant for both disorders. The co-morbidity between the disorders was primarily (63%) due to additive genetic effects common to both disorders. Interpretation Similar to molecular genetic studies, we found compelling evidence that schizophrenia and bipolar disorder partially share a common genetic etiology. These results challenge the current nosological dichotomy between schizophrenia and bipolar disorder, and are consistent with a reappraisal of these disorders as distinct diagnostic entities.

The Swedish Twin Registry was first established in the late 1950s. Today it includes more than 170,000 twins — in principle all twins born in Sweden since 1886. In this article we describe some ongoing and recently completed projects based on the registry. In particular, we describe recent efforts to screen all twins born between 1959 and 1985, and young twin pairs when they turn 9 and 12 years of age. For these studies, we present initial frequencies of common conditions and exposures.

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IntroductionThe objective of this study was to present the Swedish Pregnancy Register and to explore regional differences in maternal characteristics, antenatal care, first trimester combined screening and delivery outcomes in Sweden.Material and methodsThe Pregnancy Register (www.graviditetsregistret.se) collects data on pregnancy and childbirth, starting at the first visit to antenatal care and ending at the follow‐up visit to the antenatal care, which usually occurs at around 8–16 weeks postpartum. The majority of data is collected directly from the electronic medical records. The Register includes demographic, reproductive and maternal health data, as well information on prenatal diagnostics, and pregnancy outcome for the mother and the newborn.ResultsToday the Register covers more than 90% of all deliveries in Sweden, with the aim to include all deliveries within 2018. The care providers can visualize quality measures over time and compare results with other clinics, regionally and nationally by creating reports on an aggregated level or using case‐mix adjusted Dash Boards in real time. Detailed data can be extracted after ethical approval for research. In this report, we showed regional differences in patient characteristics, antenatal care, fetal diagnosis and delivery outcomes in Sweden.ConclusionsOur report indicates that quality in antenatal and delivery care in Sweden varies between regions, which warrants further actions. The Swedish Pregnancy Register is a new and valuable resource for benchmarking, quality improvement and research in pregnancy, fetal diagnosis and delivery.

In the largest and most comprehensive sample yet studied, we confirm the accepted estimates of recurrence risks for schizophrenia, and provide more accurate estimates of recurrence risks of schizophrenia in relatives, an estimate of the familial impact of schizophrenia, and the multiplex proportion (essential for gauging the generalizability of findings from multiplex pedigrees). These data may be valuable for planning and interpreting genetic studies of schizophrenia.