BACKGROUND: The schizotypal personality disorder is a recent psychiatric nosological concept developed by Spitzer at the end of the 1970s, based on the analysis of the characteristics of relatives of schizophrenic subjects included in the adoption studies carried out in the same decade by Kety, Wender and Rosenthal. HISTORICAL ASPECTS: However, this entity is based on older observations, at the beginning of the past century, showing common behavioural characteristics in relatives of schizophrenics. Its status within our current nosography remains dubious, sometimes classified among personality disorders, sometimes in the schizophrenia spectrum disorders. It is interesting to present the origins of this concept that stem from two complementary approaches: a family approach and a clinical approach of sporadic cases and then to redefine the framework within which the diagnostic approach was based and its continuity, up until our current classifications, the DSM and CIM. CURRENT STATUS: The historical origins cannot summarize the disorder and it appears important to redefine the multidimensional characteristics of the schizotypal personality disorder, generally a three-factor model. Indeed, dimensional models of psychosis are becoming established as conceptually and clinically useful. Recent studies on the dimensionality of psychosis show an evolution of the schizotypal concept, initially defined as being part of the schizophrenia spectrum and which now appears to be more broadly linked to a concept of unitary psychosis, including the bipolar disorder. CONCLUSION: Dimensions of psychosis seem to be associated with different familial aggregation and risk of psychosis, suggesting that they are underlined by different physiopathological processes. Hence, the dimensional approach can help to disentangle the genetic heterogeneity of the disease.