Psychoses of the Schizophrenic Spectrum in Twins: A Discussion on the Nature-Nurture Debate in the Etiology of "Endogenous" Psychoses Book

Foreword.- Introduction: The diagnostic dilemma in psychiatry; The nature – nurture controversy; Methods of clinical genetics in psychiatry.- General remarks on twin origination: Biology of twin origination; Frequency of twin births.- The twins method in research: Characteristics of the twin constellation; The methodological basis of twin research; Classical twin studies in schizophrenia research; Studies of monozygotic twin pairs discordant for schizophrenia; Leonhard’s findings on twins.- Further questions.- Methodology of a systematic twin study: Twin survey methodology and zygosity diagnosis; Methodology of psychiatric diagnostics; Determining the criteria for concordance/discordance; Selection of further test variables.- Results: Results of the twin survey and zygosity diagnosis; Psychiatric diagnoses; Demographic data of the subjects; Concordance rates; Case studies; Summary of the family history; Birth history in the intra-pair comparison; Role assignment in the twin constellation; Handedness of test persons.- Discussion: Role assignment (dominant/subordinate) and handedness; Comparability of diagnoses; Demographic data in multi-diagnostic comparison; Varying genetic dispositions; The absence of schizophrenic subgroups among twins; The influence of pre- and perinatal complications; The role of prenatal developmental disorders.- Summary.- Conclusion.- Appendix: Synoptic tables.- Bibliography.- Index.- Acknowledgements.