Initial analyses were conducted using SOLAR (Almasy and Blangero, 1998) to test the alcohol dependence diagnosis with and without the temporal clustering of symptoms for evidence of familial resemblance that would be consistent with genetic transmission. Similar analyses were conducted for the 12 alcohol dependence symptoms assessed by the SSAGA (see Table 1 for list of symptoms). SOLAR estimates an h2 parameter by partitioning the trait relative pair covariance into additive genetic and environmental contributions while correcting for any covariates included in the model. Participant’s age at the time of evaluation and sex were evaluated as potential covariates and retained if they accounted for at least 5% of the total variance. The probability that h2 was greater than zero was determined using a Student’s t-test for each scale. This test of significance was used to evaluate the potential genetic transmission of the alcohol dependence phenotypes and constituent symptoms. Corrections for multiple testing were not made given the correlated nature of the alcohol dependence symptoms.
