Schizophrenia is an ethologically heterogeneous disorder with a complex gene environment interaction as the most likely cause. A number of susceptibility genes, such as DTNBP, NRG1, DISC1, G72 and others have been identified. However their pathophysiological mechanisms are not yet fully understood. Further, a number of environmental factors (birth complications, cannabis abuse, etc) have been replicated as risk factors. Traditionally, Schizophrenia is being diagnosed according to psychopathological criteria. Yet, there is little data on the interaction between etiological factors, psychopathology and brain function/structure. On the behavioural level, psychopathological symptoms can hardly separate the many pathophysiological subgroups. Contrary to nosological categories, biologically based phenotypes - referred to as intermediate phenotypes - consisting of neuropsychological, electrophysiological, functional and structural brain imaging parameters, could represent the etiological basis more directly, but these findings have to be linked to psychopathology. In this presentation, we will try and bridge the gap between these levels of description in an attempt to disentangle nosological and dimensional features of psychosis.