Even the precursors of modern-day schizotypal personality disorder were linked theoretically to schizophrenia. Bleuler's (1922) concept of latent schizophrenia, which consisted of mild or attenuated symptoms of schizophrenia without deterioration into psychosis, was one of the major clinical forerunners of schizotypal personality disorder. The term schizotype, coined by Rado (1956), denoted a presumed nonpsychotic phenotypic variant of the schizophrenia genome. This term was later used to refer to the "borderline schizophrenia" syndrome identified in the Danish adoption studies, which was a milder schizophrenia-like disorder found in the biological relatives of probands with schizophrenia (Kety et al. 1968).