Trust is central to the relationship between doctor and patient. An important skill in psychiatry, therefore, is the ability to relate to and effectively treat patients in whom the capacity for trust is diminished as a consequence of psychopathology. The focus of this chapter is paranoid personality disorder, a condition in which mistrust of other people is the cardinal feature. It is not an uncommon disorder, with a prevalence in community samples of around 1.3% (Torgersen, 2005), rising to up to 10% in psychiatric outpatient samples (Bernstein et al, 1993). Despite this, the research base on the disorder remains relatively sparse (Bernstein & Useda, 2007).

Diagnosis

Clarifying the diagnosis of a patient with paranoid thinking is an essential first step to management, with ramifications for prognosis, treatment and medico-legal issues such as involuntary treatment or criminal responsibility. The DSM-IV-TR criteria for paranoid personality disorder (American Psychiatric Association, 2000) have been criticised for underrepresenting the typical affective and interpersonal features of the disorder, features that give a richer sense of the typical presentation (Bernstein & Useda, 2007) (Box 4.1).