At the current time there is no definitive measure to predict suicide or suicidal behavior. Researchers have identified factors that are associated with higher risk for suicide. These include mental illness, previous suicide attempts, family stress and dysfunction, family history of suicide, physical or sexual abuse, family violence, traumatic death of a loved one, and impulsive or aggressive tendencies. Alcohol and substance abuse can contribute to suicidal behavior. Substance abuse can be common among teens prone to be impulsive, and among those who engage in many types of high risk behaviors that result in self-harm. In addition to being depressed, those who are dependent on substances are also likely to have social problems. Suicide is a relatively rare event and it is therefore difficult to predict which persons with these risk factors will ultimately commit suicide.