The Washington University Twin Study of alcoholism.
Level 4 - case-series / case-control
Observational clinical twin study
PubMed 15704214 · doi:10.1002/ajmg.b.30124
What was done
Twins from 295 pairs were consecutively ascertained at inpatient and outpatient psychiatric and alcohol treatment facilities in St. Louis, Missouri, between 1981 and 1986. Probands and participating cotwins were evaluated using structured psychiatric interviews, psychometric assessment, and lifetime treatment records. A total of 154 probands met criteria for alcohol abuse/dependence (AAD), including twins from 45 monozygotic (MZ), 50 same-sex dizygotic (DZ), and 59 opposite-sex pairs. Twin-pair resemblance was assessed for AAD and alcohol dependence (AD), as well as subgroups defined by sex, comorbidity patterns, ethnic background, and clinical features.
What was found
The abstract reports directions of effect without numerical point estimates, standard errors, or p-values. Male heritability for AAD and AD was substantial, with little evidence for shared environmental contributions. In females, pair resemblance was substantial but equivalent between MZ and DZ pairs, leading to near-zero heritability estimates; however, sex differences did not reach statistical significance. No evidence of higher heritability was found for male early-onset alcoholism or alcoholism comorbid with antisocial personality disorder.
Why it matters
The findings support strong genetic influences on male alcoholism liability while suggesting potential differences in genetic architecture or environmental susceptibility in females, though larger samples are required to confirm heterogeneity.
Limits
The abstract reports no numerical values, effect sizes, or confidence intervals. The sample size of 154 affected twin pairs provided limited statistical power to resolve sex differences or subtype heterogeneity. As a clinically ascertained cohort from a single metropolitan region, findings may not generalize to community populations.
Cited by
- context In genetic studies of alcohol use disorder, the father-to-son transmission link is the strongest observed across sexes.