Maternal and paternal alcohol dependence symptoms were indexed using lifetime symptom counts for DSM-3-R (American Psychiatric Association, 1987) Alcohol Dependence as assessed using the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA; Bucholz et al., 1994) when the twins were age 12. Total symptom counts, which ranged from 0–9, were used in analyses. If only one parent’s data were available, his/her score was used (11% of sample only had mother data, 1% only had father data, and <1% were missing data on both parents). When both mother and father data were available (87% of the sample), the maximum score was used in analysis. For 57% of these participants, the maximum score was from the father, for 10% the maximum score was from the mother, and for 33% the mother and the father had the same score. Maternal symptoms ranged from 0–9 (M = 0.58), and paternal symptoms ranged from 0–9 (M = 2.07), and 33 and 137 of mothers and fathers endorsed three or more criteria and met clinical criteria for alcohol dependence. Mother and father scores were positively correlated, τ = .17, p < .01.
