In recent years, neurobiological research in the development of bipolar disorder has contributed to a number of important findings. Studies of neurochemical and molecular-biological changes in the brain, structural abnormalities as well as a variety of genetic investigations have consolidated the current view of a multifactorial genesis. A further focus has been on the influence of psychosocial factors and neuropsychological parameters in the development of bipolar disorder. The following article describes key findings from recent research on neurobiological and psychosocial factors in the development of bipolar disorder with a focus on molecular-biological and structural brain changes which represent the basis for future successful approaches in prospective research.