Previous studies have suggested that biological --- but not adoptive--- relatives of adopted children who commit suicide have a higher suicide risk than do the biological relatives of adopted persons who have not committed suicide.

The researchers found that parents who attempted suicide made the initial attempt around age 30 years, and 56 percent of them had made multiple attempts. Compared with people who had not made a suicide attempt, the first group of parents was more likely to have been exposed to sexual abuse (39 percent versus. 18 percent). However, there was no difference between the two groups of parents with regard to physical abuse.

When the researchers studied the children, they found that 12 percent of children of parents who had attempted suicide had themselves attempted suicide. In contrast, only 2 percent of the children of parents who had not made an attempt had made an attempt themselves. The authors also found that 82 percent of suicide attempts by children occurred within the context of a mood disorder such as depression.

The authors write, "This high-risk family study found a strong and specific familial transmission of early-onset suicidal behavior from parent to child. Offspring of attempters had a six-fold increased risk for a suicide attempt relative to offspring of nonattempters, comparable to rates reported in adoption, twin, and family studies of suicide and suicidal behavior."

The authors conclude "... parents with mood disorders who have made suicide attempts and have been sexually abused are highly likely to have children who attempt suicide. Conversely, children with mood disorders are at greater risk for an attempt if they also show evidence of impulsive aggression, have been sexually abused, and have parents with the aforementioned risk factors."