Final Activity Report Summary - EUTWINSS (European Twin Study Network on Schizophrenia) EUTWINSS, the European Twin Study Network on Schizophrenia, has been established as a multi-centre collaboration within the European Research Area to combine previously existing bilateral and multilateral collaborations into a larger-scale network capable of integrating different research methods. The project has integrated 9 nodes in 6 countries. Schizophrenia, which is one of the most serious and chronic mental illnesses, has long been assumed to arise from a combination of both genetic as well as environmental factors. Twin studies are a method to estimate the genetic and non-genetic contributions to a given biological marker, which is an important factor for its use as an indicator or even predictor of disease. The EUTWINSS network has used a collaboration of several centres to establish large databases of twin data, including brain scans from twins with and without schizophrenia, data on cognitive functioning, genetic markers, and other biological tests that could serve as an endophenotype. The multidisciplinary composition of network, including centres specialised in brain imaging, genetics, neuropsychology, statistical modelling and other areas, has provided a leading framework for the interdisciplinary training of research fellows employed in the project. Among the main research achievements of the project, the network has performed several studies on genetic and non-genetic effects on brain structure, using the largest twin sample available internationally. Data from previous and current investigations have been combined to establish the influence of genetic impact on specific brain areas. Several studies have been published (or are prepared) that include analyses of total brain volumes, lobar volumes, voxel-based morphometry, cortical thickness, and gyrification in subsamples. For the first time, such analyses have been done in large twin studies, and the results have shown both the distribution of genetic effects in different brain areas as well as the influence of genetic factors in the potential progression of brain structural changes in schizophrenia. Studies on neuropsychological tests have revealed that several cognitive functions such as certain tests of working memory show shared genetic influence with schizophrenia, which suggests that same or similar genes (potentially affecting brain development) influence the illness as well as these specific cognitive functions in humans. Several genetic studies have been performed, studying both risk genes for schizophrenia and epigenetic mechanisms in twin samples. The training component of EUTWINSS has provided young researchers coming from different scientific backgrounds with a core curriculum, including courses on twin research methodology, psychiatric research, the biology of schizophrenia and other topics. Educational activities have involved both local-level training (e.g. PhD courses, teaching through lab research), as well as network-level components. The latter have included annual workshops for fellows (with lectures/courses by expert external speakers, senior scientists of the network, and presentations from the researcher recruited within the network), furthermore secondments and research visits, and an eLearning platform for dissemination of material within the network. EUTWINSS has therefore built on previous collaborations to combine provision of high-quality specialised training to young researchers, to strengthen collaboration between several European research facilities, and use synergy between these. Based on this largest twin study on schizophrenia today, it has also provided the basis for future collaboration in other related psychiatric conditions and has established the consortium as a leader in the field of multimodal twin research in psychosis.
