66 By and large, the F/S classification has not so far identified homogeneous groups for genetic research, possibly due to the likely presence of unexpressed genotypes in schizophrenia families.67 The present see more diagnostic classifications: DSM-IV and ICD-10 While European psychiatry rarely departed in a significant way from the nosological concepts formulated Inhibitors,research,lifescience,medical by Kraepelin and his followers, the practically undisputed dominance of psychodynamic psychiatry in North America over many decades came to an end with the “neo-Kraepelinian revolution” of the 1970s.68 The development of operational diagnostic

criteria,69,70 which were presumed to reflect the Kraepelinian categorical nosology, and their incorporation in the Third Edition of the Diagnostic and Statistical Manual of the American Inhibitors,research,lifescience,medical Psychiatric Association, DSM-III,19 was a turning point in the conceptualization of psychiatric disorders in general and of schizophrenia in particular. The likely gains in the reliability and reproducibility of diagnostic assessment based on explicit rules and criteria led to the Inhibitors,research,lifescience,medical adoption of a similar approach in the mental disorders chapter of the 10th revision of the World Health Organization’s

International Classification of Diseases, ICD-10,20 which in turn provided a stimulus for the development of DSM-IV.71 The diagnostic Inhibitors,research,lifescience,medical criteria of ICD-10 and DSM-IV were originally conceived with a view to achieving three fundamentally different goals: (i) to identify groups of patients with broadly similar clinical presentation and prognosis; (ii) to facilitate early diagnosis and choice of treatment; and (iii) to define a homogeneous heritable diagnostic category for genetic and other aetiological research.72 While the the first two goals have, by and large, been achieved as regards clinical utility of the criteria, attainment

of the Inhibitors,research,lifescience,medical third goal remains remote. There are both similarities through and differences in the way the two classifications define schizophrenia. In contrast to DSM-IV, which provides a single set of “operational” diagnostic criteria for all users, ICD-10 was designed as a “family” of inter-related versions addressing different users. While the ICD-10 volume Clinical Descriptions and Diagnostic Guidelines is the conceptual “core” of the system, the ICD-10 Diagnostic Criteria for Research and the WHO Guide to Mental Health in Primary Care are derivatives for use in specific context.72 A comparison of the two sets of diagnostic criteria (in an abridged format) is provided in Tables IV and V. Table IV Table IV. ‘Candidate’ endophenotype markers in schizophrenia research (reviewed in ref 72). Table V Table V. ICD-10 / F2 group of disorders.