summary The prodromal phase of a (schizophrenic) psychosis may be characterized by non-specific problems in many areas, so that at first a personality disorder is expected. Especially the differential diagnosis with a borderline personality disorder is troublesome, because this disorder includes (marginal) psychotic symptoms. The results are presented of a retrospective pilot study in which there has been made a comparison between a group of psychotic patients (afterwards diagnosed), and a group of patients with a (borderline) personality disorder.