During the last century some authors have considered premorbid personality and psychosis as part of a continuum, while others have interpreted these phenomena as independent. The continuum model strictly associating personality disorders and schizophrenia was supported by family studies (first of all the Danish adoption studies) and gave rise to the construct of “schizophrenia spectrum disorders”, which included “borderline schizophrenia”. In the 1980s, the DSM-III divided “borderline schizophrenia” into two nosographical entities 1: schizotypal personality disorder (SPD), characterized by diagnostic criteria that identified personality traits typical of relatives of schizophrenic patients 2; and borderline personality disorder (BPD), initially described without including psychotic symptoms, but very similar to the Hoch and Polatin’s concept of “pseudoneurotic schizophrenia”. The aim of this study was a systematic revision of literature on the relationship between SPD, BPD and psychotic disorders.
Moving from the historical origin of psychopathological and diagnostic constructs, we examined clinical characteristics and relationships among these disorders. The most recent findings in studies of neuroscience have also been considered.
Patients with SPD exhibit a vulnerability to schizophrenia, while BPD is characterized by a stress-related reactivity that induces brief self-limiting psychotic episodes.
The existence of a relationship between specific personality disorders and psychosis may suggest that premorbid personality is not only a risk factor for the onset of psychotic symptoms, but also a predictive factor for the course and outcome of psychotic disorders.
However, this relationship seems to be explained by different and quite heterogeneous factors that are difficult to describe with DSM-IV categories and criteria. The new partly dimensional criteria proposed by the task force for DSM-5 personality disorders have been examined with respect to their ability to define and clarify this issue.