3,416 Missouri female adolescent twins were interviewed by telephone from 1995-2000. At least one suicide attempt was reported by 4.2% of the subjects. First suicide attempts all occurred before age 18. Major depressive disorder, alcohol dependence, childhood physical abuse, social phobia, conduct disorder, & African-American ethnicity were the factors most associated with a suicide attempt history. Suicide attempt liability was familial, with genetic & shared environmental influences together accounting for 35-75% of the variance in risk. (50 refs.)