[Nosology, genetics, neurobiology, and psychopharmacology of schizophrenia]

The development of psychiatric nosology is outlined, and five principles responsible for the organization of psychopathologic symptoms into psychiatric disorders are proposed. Within the frame of reference of the nosologic organizing principles, the evolution and dissolution of the unitary concept of schizophrenia are reviewed, and some of the findings in neurobiologic, genetic and psychopharmacologic validation studies are discussed. It is suggested that findings in family genetic studies and in clinical psychopharmacologic investigations are supportive of Leonhard's (1957) contention that systematic and unsystematic schizophrenia are two distinct populations.