Is there a way to measure someone's suicide risk?

A brain scan might be able to predict who might attempt suicide. — TNS

When a person’s distress, depression or discouragement appears to have taken a sharp turn for the worse, it’s time to ask him or her a weighty question: Are you thinking of harming yourself?

If only the answer were a better guide. One study has found that nearly 80% of patients who took their own lives denied they were contemplating suicide in their last contact with a mental health care professional.