The workshop will give an overview of distinct neurophysiological and brain imaging studies with patients suffering from Borderline personality disorder and from depressive affective disorder. The contribution of Jose Manuel De la Fuente will report findings of sleep EEG recordings of patients with Borderline personality disorder (BPD), Major Depression (MD), Recurrent Brief Depression (RBD), and of controls. It was detected that BPD patients expressed less slow wave sleep than MD and RBD patients without BPD. Oliver Pogarell performed a radioligand brain imaging study that revealed an increase of the availability of the specific serotonin transporter (SERT) in the hypothalamus and brain stem of BPD patients which is in contrast to the findings of a SERT decrease in patients with depression. Christine Norra recorded event-related auditory evoked potentials (AEP) obtained through the application of various loudness stimuli. The strong loudness dependency of AEP in patients with BPD correlated with aspects of impulsiveness which may point to a serotonin disturbance in this disorder. Thomas Zetzsche and his collegues performed a quantitative volumetric magnetic resonance imaging (MRI) analysis of temporolimbic regions in patients with BPD and MD. They found a significant increase of amygdala volume both in BPD patients with comorbid MD and in MD patients without BPD. Comparison of abnormal neurobiological findings between BPD and MD could provide a better insight into potential differences but also into similarities of the pathophysiology of these important psychiatric disorders.