This article aims to explore & explain some possible antecedents to behaviours revealed by consumers in mental health settings who evoke strong & often negative responses in nurses & other health professionals. The contemporary example is people diagnosed with a borderline personality disorder. The paper discusses four different but overlapping domains that may contribute to understanding the difficulties many nurses face in relation to working with consumers whose behaviours are complex & distressing. The last of these domains, behavioural concomitants of projection, splitting & projective identification includes identity diffusion, self-mutilation & suicide attempts. Strategies to help nurses support these consumers in expressing their pain in more constructive ways are explored. (26 refs.)