Borderline personality disorder (BPD) is a highly studied condition. During the last 3 decades, the understanding of the disorder has substantially changed, based on thorough, accumulating research. At the same time, the interest in BPD is still not decreasing but continues to grow. This article aims to critically discuss research trends in clinical trials of personality disorders in general and BPD in particular, to highlight topics that deserve closer attention, and to give recommendations for the design and conduct of future psychotherapy or pharmacotherapy studies in the field.