Impulsiveness is the tendency to act without thinking through a plan or its consequences. It is a symptom of a number of mental disorders, and therefore, it has been linked to suicidal behavior because of its association with mental disorders and/or substance abuse. The mental disorders with impulsiveness most linked to suicide include: borderline personality disorder among young females, conduct disorder among young males, antisocial behavior in adult males, and alcohol and substance abuse among young and middle-aged males. Impulsiveness appears to have a lesser role in older adult suicides. Attention deficit disorder with hyperactivity and impulsivity is not a strong risk factor for suicide by itself. Impulsiveness has been linked with aggressive and violent behaviors including homicide and suicide. However, impulsiveness without aggression or violence present has also been found to contribute to risk for suicide.