Normal personality, personality disorder and psychosis: current views and future perspectives

The purpose of this article is to review recent literature examining the occurrence of psychotic experiences in normal population and those with personality disorders.

Up to 15% of individuals in the general population report some type or degree of psychotic experience. Most of these individuals function adequately, do not require psychiatric treatment and do not receive diagnosis of a psychotic illness. A significant number of individuals diagnosed with borderline personality disorder (25-50%) also report psychotic symptoms. These are not easily differentiated from the psychotic symptoms reported by individuals with schizophrenia, nor are they always transient. However, emerging research has confirmed that individuals with schizotypal personality disorder are dimensionally related to those with schizophrenia and are at an increased risk of transition to psychosis.

Psychotic symptoms are best considered as 'trans-diagnostic' entities on a continuum from normal to pathological. There is a large body of evidence for a dimensional relationship between schizotypal personality disorder and schizophrenia. There is also a significant amount of research showing that psychotic symptoms in borderline personality disorder are frequent, nontransient and represent a marker of illness severity. This review highlights the need to move beyond traditional assumptions and categorical boundaries when evaluating psychotic experiences and psychopathological phenomena.