ABSTRACT
The four major criticisms of the neo-Kraepelinian classifications are that the categories lack independence, principles underlying them are diverse, they are too heterogeneous, and the reliability and validity of diagnoses are too low to be of any value. The presumed fundamental distinctions between normality and the psychopathologies in general have proved tantalizingly elusive for those committed to the classification system. All of the symptoms associated with each of the disorders are experienced to a greater or lesser extent by all of us at some time or other. The homogeneity argument has very often been raised specifically in relation to the category of schizophrenia. Meyer's psychobiological approach places its emphasis on regarding the patient as a unique individual, who cannot be broken down into lists of symptoms or categorized alongside others with superficially similar clinical pictures. One fundamental rule concerning classification systems is that the type of material used to define the attributes of the various categories should be consistent throughout.
