"We can often get enough of an idea of when illness began by looking for a change in their social functioning," Lamberti said. "If we know someone has a diagnosis and had onset before a particular event, that certainly raises the possibility that they were psychotic at the time of the event. But that's when it becomes important to do psychiatric evaluation as close to the event as possible and gather eyewitness accounts."
While mental illness is known to run in families, Lamberti stressed that people without affected relatives are not immune. The schizophrenia risk for someone with no affected relatives is still 1 percent, jumping to 10 percent for someone with an affected parent or sibling.
But if a family member starts to show symptoms of psychosis, Raison said it should be considered an emergency on par with a heart attack or stroke.
"The sooner you treat people with medication, the better chance you have of sort of slowing this nasty condition," he said. He believes Loughner could recover with the proper treatment. "Sometimes people regain clarity and are able to tell you in very disturbing detail what they've done, and that can be horrifying. People like that are at risk for suicide."
Loughner is said to be on suicide watch.