Family history of suicide, female sex, and childhood trauma: separate or interacting risk factors for attempts at suicide?

OBJECTIVE: Female sex, childhood trauma, and a family history of suicidal behavior are three well established risk factors for attempting suicide. However, interactions between these three factors in attempting suicide have been little studied.
METHOD: One thousand eight hundred and eighty-nine abstinent substance dependent patients were interviewed about their lifetime and family history of suicidal behavior and completed the Childhood Trauma Questionnaire (CTQ). Gender, family history of suicidal behavior, and CTQ scores--and their interaction--were examined in relation to suicidal behavior.
RESULTS: Each of the three risk factors was associated with at least a doubling of the risk for an attempt at suicide. There were no significant interactions in relation to the risk of making an attempt. However, female sex and higher levels of childhood trauma each discriminated patients at risk for both a younger age of first attempting suicide and for making more attempts.
CONCLUSION: Female sex, childhood trauma, and a family history of suicidal behavior are each independent, and non-interacting, risk factors for attempting suicide. Additionally, female sex and high childhood trauma are independent risk factors for both an early onset of first attempting suicide and for making more attempts.