Mental illnesses have a multifactorial etiology with a high heritability. Different polymorphisms of candidate genes are believed to susceptibility factors that increase the risk to develop a psychiatric disorder. Nowadays, it is general accepted that the individual risk for mental illness is composed of the interplay of genetic susceptibility and  environmental factors. Here, epigenetic mechanisms are believed to be the underlying mediators between genes and environment. Until now, the pathogenetic mechanisms of the; psychiatric diseases such as autisms, anxiety disorders as well as schizophrenia are unknown. Identification of the underlying molecular mechanisms is thus crucial for understanding of pathogenesis and for developing novel therapeutic targets for these diseases.Using a combined molecular biological, physiological and behavioural approach, we investigate the pathogenetic mechanisms of these diseases on molecular, cellular, network and behavior level in; both human and animal models: a) identification of functional or positional candidate genes that play a role in the pathogenesis of psychiatric disorders (e.g.anxiety disorders, schizophrenic disorders) in humans. b) analyzing epigenetic processes and their functional consequences to uncover the underlying mechanisms which differentially regulate susceptibility genes using different mouse models.c) investigating the functional role of different key molecules, such as neuregulin, ErbB4, RGS, neuroligin, neurexin, DHHC7 etc., in brain function.d) studying genetic and environmental influences on behavioral endophenotypes using mutant mouse models