Psychiatric nurses are familiar with the concept of personality disorder because of their contact with persons with the most common personality disorder in clinical settings - borderline type, who frequently engage mental health services. Perhaps it is this familiarity that has focused research and clinical attention on borderline personality disorder compared with the other personality disorders. The significance of cluster A personality disorders for nursing is multifaceted because of their severity, prevalence, inaccurate diagnosis, poor response to treatment, and similarities to axis I diagnoses. Despite this, literature reviews have established that relatively few studies have focused on the treatment of the cluster A personality disorders - paranoid, schizotypal, and schizoid - resulting in a dearth of evidence-based interventions for this group of clients. A discussion of these disorders in the context of personality disorder and their individual characteristics demonstrates the distinctive and challenging engagement techniques required by psychiatric nurses to provide effective treatment and care. It is also strongly indicated that the discipline of psychiatric nursing has not yet begun to address the care of persons with cluster A personality disorders.