Parental treatment and the equal environment assumption in twin studies of psychiatric illness.

@article{Kendler1994ParentalTA,
  title={Parental treatment and the equal environment assumption in twin studies of psychiatric illness.},
  author={Kenneth S. Kendler and Michael C. Neale and Ronald C. Kessler and Andrew C. Heath and Lindon J. Eaves},
  journal={Psychological medicine},
  year={1994},
  volume={24 3},
  pages={
          579-90
        }
}
The validity of the twin method depends on the equal environment assumption (EEA)--that monozygotic (MZ) and dizygotic (DZ) twins are equally correlated in their exposure to environmental factors of aetiological importance for the trait under study. Parents may treat MZ twins more similarly than DZ twins thereby potentially violating the EEA. We tested this hypothesis for four common psychiatric disorders (major depression, generalized anxiety disorder, phobia, and alcoholism) in a population… 
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References

SHOWING 1-10 OF 43 REFERENCES
A test of the equal-environment assumption in twin studies of psychiatric illness
TLDR
A newly developed model-fitting approach which treats perceived zygosity as a form of specified familial environment is used which supports the validity of the EEA in twin studies of psychiatric disorders.
Twins: a test of the equal environments assumption
TLDR
The extent of imposed similar treatment received during childhood and early adolescence was unrelated to either MZ or DZ twins’ current behavioral similarity, as indicated by absolute intrapair differences in their Neuroticism, Anxiety, and Depression scores.
A genetic and environmental analysis of a twin family study of alcohol use, anxiety, and depression
TLDR
This study illustrates that data from twins and their relatives which includes information on cohabitation history might distinguish shared genes and shared environment as causes of familial aggregation in twin family data.
Twin method: Defense of a critical assumption
TLDR
Perceived zygosity and perceived similarity by self and others were found to be insignificant biases in the twin study method.
A twin study of hyperactivity--II. The aetiological role of genes, family relationships and perinatal adversity.
  • R. Goodman, J. Stevenson
  • Psychology, Medicine
    Journal of child psychology and psychiatry, and allied disciplines
  • 1989
In a large representative sample of 13-year-old twins, monozygotic pairs were more alike than same-sex dizygotic pairs on objective measures of attentiveness and on parent and teacher ratings of…
Interactive effects of genotype and social environment on alcohol consumption in female twins.
TLDR
In the young sample (average age 35 years), there is no evidence that individuals genetically predisposed to heavy drinking are any less likely to be married than the rest of the population, and statistical analyses show that marital status is an important modifier of genetic effects on drinking habits.
Generalized anxiety disorder in women. A population-based twin study.
TLDR
GAD is a moderately familial disorder and the tendency for GAD to run in families seems to be due largely or entirely to genetic factors shared between relatives rather than to the effects of the familial environment.
A population-based twin study of major depression in women. The impact of varying definitions of illness.
TLDR
Nine commonly used definitions of major depression, which produced life-time prevalence rates ranging from 12% to 33%, were examined and the results of model fitting to twin correlations suggested that the liability to depression results from genetic factors and environmental experiences unique to the individual.
A population-based twin study of alcoholism in women.
TLDR
The results support the hypothesis that genetic factors play a major role in the etiology of alcoholism in women and women should be well represented in the efforts currently under way to elucidate the molecular basis of the genetic susceptibility to alcoholism.
Environmental bias in twin studies.
  • S. Scarr
  • Psychology
    Eugenics quarterly
  • 1968
TLDR
This study examines the responses of mothers of twin girls about similarities and differences of their monozygotic (MZ) and dizygotic (DZ) twins, and finds that 11 pairs of twins were misclassified by their mothers.
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