Heredity and Environment in the Functional Psychoses

Heredity and Environment in the Functional Psychoses involves an epidemiological clinical study of twins carried out at the University Psychiatric Institute in Oslo. The author reviews the history and nosological aspects of psychiatry. In his study of twin genetics, the author seeks to answer the questions "What is inherited?" and "How is it inherited?" In his review of 342 pairs of twins in the Central Register of Psychosis, his study had the following aims: to obtain true concordance figures for all types of functional psychoses; to study problems pertaining to nosology; and to study a larger sample of discordant pairs in order to clarify crucial environmental factors. His findings show that concordance figures for schizophrenia are 25-38 per cent in monozygotic twins and 4-10 per cent ion dizygotic twins. He points out that the difference in such concordance rates between the two types of twins is statistically significant. The data supports the (weak) assumption of a genetic factor in the etiology of schizophrenia. Behavioral scientists, psychiatrists, child psychologists, and researchers involved in genetics will find this book helpful and informative.

I Introduction

Historical Survey

Schizophrenia

Nosological Aspects

Heredity and Environment

The Rationale of the Twin Method

Methodological Problems

General Remarks

Concordance Figures

Brief Review of Earlier and Current Twin Studies

General Remarks

Twin Studies in Psychosis

II Aims of the Investigation

III Sample and Methods

The Registries

The Birth Register

The Twin Register

The Central Register of Psychosis

Comparison of the Twin Register with the Register of Psychosis

Hospital Records

The Population Registers

Zygosity Diagnosis

Psychiatric Investigation of the Families

An Anecdote

The Reliability of the Psychiatric Interview

Supplementary Information

Coding of Data

IV Classification

Psychiatric Diagnosis

Schizophrenia

Schizophreniform Psychosis

Borderline States

Reactive Psychosis

Manic-Depressive Psychosis

Organic Psychosis

Neurosis

Psychopathy

Syndrome Diagnosis

Global Mental Health Rating

Reliability of Psychiatric Classification

V Statistical Procedure

VI Frequency of Functional Psychosis in the Twin Sample in Comparison with the General Population

Discussion

VII Survey of the Sample

Sex, Age, Zygosity

Age at Onset of Schizophrenia

Type of Onset

VIII Concordance

Calculation of Concordance Rates

Concordance Figures

Schizophrenia

Reactive Psychosis

Manic-Depressive Psychosis

Summary of the Monozygotic Pairs with Regard to Concordance

Sex and Concordance

Severity and Concordance

Discussion of Methodology

Sources of Error due to Sampling

Sources of Error due to Doubtful Zygosity Diagnosis

Sources of Error due to Risk Period

IX Comparison of Own Findings to Previous Studies

Concordance Figures for Schizophrenia

Sex and Concordance in Schizophrenia

Severity and Concordance in Schizophrenia

Concordance Figures for Manic-depressive Psychosis

Sex and Concordance in Manic-Depressive Psychosis

X The Co-Twin's Personality

The Co-twins of the Schizophrenic Monozygotic Twins

Discussion

The Co-twin of the Monozygotic Twin with Reactive Psychosis

The Co-twin of the Manic-depressive Monozygotic Twin

Comparison of Syndromes

XI The Twin Relationship

XII Factors in Childhood and Adolescence Related to Schizophrenia

Birth Order, Birth Weight, and Physique

Personality Traits in Childhood

Nervous Symptoms in Childhood

School Performances

Premorbid Personality Traits

Sex Life

Social Adjustment

Discussion

XIII Comparison between the Schizophrenic Concordant and Discordant Cases

The Genetic Hypothesis

The Environmental Hypothesis

XIV The Social Environment

Social Class

Social Isolation

Family Relations

XV The Parents and the Siblings

Personality Deviations and Illness in the Parents

Personality Deviations in the Siblings

Association of Mental Health by Sex

Impressionistic Data on the Sibling Positions

XVI Twins Brought Up Apart

Own Findings

Discussion

XVII General Discussion and Conclusion

XVIII Summary

Appendix 1 Summary Table of the Monozygotic Pairs

Appendix 2 Four Twin Case Histories

Appendix 3 Explanatory Notes and Abbreviations

Appendix 4 Papers Based on Research Reported in this Book

References

Author Index

Subject Index

Publisher's Note

The Case Histories of the Schizophrenic and the Schizophreniform Twins and Their Cotwins are to Be Found in a Second Volume (In This Book Designated Volume 2 ) Which has been Printed on Offset by Universitetsforlaget