Key study sheet Kendler et al 1992
KEY STUDY ______________Level of Analysis
Research data: (Topic, author/s, date)
Genetics and behaviour
Kendler et al,
1992
DESCRIBE:
Key words from the syllabus/me:
Genes, MZT, DZT, Nature, Nurture, Correlational Method
Women, Alcohol
Learning outcome: nr. 11
Aim:
Examine the role of genetic and environmental factors in the etiology of narrowly and broadly defined alcoholism in women Method:
Ca. 2000 participants (twins all women)
Zygotic twins (blood samples to be certain)
Interviews with twins
Double-blind control
Concordance rate: How alike they are within a monozygotic twin-pair
Divided into four groups based on interviews:
- Unaffected
- Problem drinking
- Alcoholism withouth tolerance dependence
- Alcoholism with tolerance dependence
Difference in alcoholism are assumed to arise from:
- Addictive genetics
- Family or environment (sources shared with twin)
- Individual specific environment (all sources not shared)
Tetrachoric correlation – uses all info available
Aka Correlation of liabilty
Study uses probandwise concordance = the proportion of affected individuals among the co-twins of affected twins (probands)
Resemblance in twins is assumed to result from three factors:
- Addictive genes
- Family or common environment
- Specific environment
Results:
The proband concordance for alcoholism was higher in MZ than in DZ twins for all definitions of alcoholisms.
The tetrachoric correlations for alcoholism were substantially higher in MZ than in DZ twins for all definitions of alcholism.
Liabilty to alcoholism results solely from genetic effects and individual specific environment.
Estimated heritability of liabilty to alcoholism was ranged between 50% - 60%
Conclusion:
Study supports hypothesis that genetic factors play a major etiologic role in alcoholism for women.
Suggests that genetic factors are of
Research data: (Topic, author/s, date)
Genetics and behaviour
Kendler et al,
1992
DESCRIBE:
Key words from the syllabus/me:
Genes, MZT, DZT, Nature, Nurture, Correlational Method
Women, Alcohol
Learning outcome: nr. 11
Aim:
Examine the role of genetic and environmental factors in the etiology of narrowly and broadly defined alcoholism in women Method:
Ca. 2000 participants (twins all women)
Zygotic twins (blood samples to be certain)
Interviews with twins
Double-blind control
Concordance rate: How alike they are within a monozygotic twin-pair
Divided into four groups based on interviews:
- Unaffected
- Problem drinking
- Alcoholism withouth tolerance dependence
- Alcoholism with tolerance dependence
Difference in alcoholism are assumed to arise from:
- Addictive genetics
- Family or environment (sources shared with twin)
- Individual specific environment (all sources not shared)
Tetrachoric correlation – uses all info available
Aka Correlation of liabilty
Study uses probandwise concordance = the proportion of affected individuals among the co-twins of affected twins (probands)
Resemblance in twins is assumed to result from three factors:
- Addictive genes
- Family or common environment
- Specific environment
Results:
The proband concordance for alcoholism was higher in MZ than in DZ twins for all definitions of alcoholisms.
The tetrachoric correlations for alcoholism were substantially higher in MZ than in DZ twins for all definitions of alcholism.
Liabilty to alcoholism results solely from genetic effects and individual specific environment.
Estimated heritability of liabilty to alcoholism was ranged between 50% - 60%
Conclusion:
Study supports hypothesis that genetic factors play a major etiologic role in alcoholism for women.
Suggests that genetic factors are of