Much of the response to the shootings in Tucson, Ariz., has already shifted to debate over whether hateful political talk should be blamed or absolved. It would seem a needless discussion in the country where Revolutionary War planter Charles Lynch's name became a synonym for taking the law into your own hands.

But the shootings do point out the need for another, urgent discussion, and it is entirely apolitical. Even more clearly than in other high-profile cases of assaults by young men, accounts of Jared Loughner's prior behavior strongly suggest that he was psychotic — not just "wacky," but having a definable, treatable mental illness.

No one can make a diagnosis from a few details in a newspaper article — it is hard enough in person — but an outline of the possibility emerges. A young person (the peak age for onset of schizophrenia and manic-depressive illness is in the late teens and early 20s) gradually becomes more withdrawn, suspicious of others, and frankly, starts to say things that don't make sense. The New York Times quotes his response to a straightforward classroom math question as, "How can you deny math instead of accepting it?"

Another part of the pattern is also sadly familiar. Over an extended period, any number of people notice changes. The behavior and the statements are more than odd; often, they are frightening. The person gets angry or shifts mood out of the blue; sometimes, it is just a "creepy" feeling that the person doesn't respond to the usual signals that keep us all at a safe distance from one another.

But we mostly don't act to try to get that person help. We intuitively know that they are ill, the same as if we had noticed that they recently had lost a lot of weight or developed a limp, but by and large we seek to avoid them not help them. And it keeps getting worse — until something happens.

Mr. Loughner's college did tell him that he needed to have a mental health evaluation before he could return to school. Again, there is not enough information available to say anything about his case in particular, and we know these are difficult situations for administrators, often caught between their good instincts and what they think the law requires. But we know some of the reasons why people newly developing serious mental illnesses often don't get care until they are very ill.

One big reason is that mental illness is among the most stigmatizing labels one can propose, and it is a huge barrier to getting care. Around the world, in nearly every society, people with odd and frightening behavior get hidden or risk being abandoned by their families — not only because they can't be controlled or trusted but because they are an embarrassment and make life difficult for everyone else. All too often, mental illness is still seen as a defect of character or upbringing.

So in our society, we tend first to suspect other reasons for the behavior. We can be forgiven for some of this. We live in an era when powerful weapons are readily available, where "zero-tolerance" policies to threatening behavior trigger protective responses, and where, paradoxically, we feel little right to poke our nose into anyone's business, even as they walk toward a cliff. So the first-line assumption is often that this is a problem for the law or some disciplinary action, and we often seem to feel that response is more fair and less extreme than suggesting that what this person really needs is to see a doctor.

So what could we do? There have been some very successful educational programs for police officers and other first responders to help them recognize when a person they encounter is sick and likely not a criminal. But we need much more widespread training for educators, employers and the public about the signs and symptoms of major mental disorders and what to do when it looks like someone might be ill. We need to make it a humane and nonstigmatizing standard to empathetically but effectively get someone to a source of care when the first concerns arise — when they are much more likely to agree to it.

In some places these efforts, triggered by other tragedies, are under way — but too quietly and delicately. It is time to give them a higher profile and priority.

Larry Wissow is a child psychiatrist and professor in the Department of Health, Behavior and Society at the Johns Hopkins Bloomberg School of Public Health. His e-mail is lwissow@jhsph.edu.