Here’s a better idea for “arming” the nation’s teachers.

Let’s do it with knowledge, support and resources about the mental health of children.

The suggestion comes in the wake of the Sandy Hook Elementary School shooting, from people who understand the importance of early detection and intervention.

“Teachers must be taught how to identify troubled children early and to guide them into effective supports before these children get into difficulties,” wrote Ron Manderscheid, executive director of the National Association of County Behavioral Health and Developmental Disability Directors.

Manderscheid’s note is making the rounds among mental health professionals. Many are crafting similar messages to members of Congress.

Here’s a striking point that Manderscheid made in a blog post the day of the Sandy Hook Elementary School shooting and reiterated in the letter:

“Few young people get even a single hour of education about mental illness or addiction, its signs or its treatment. We can’t expect people to step forward or to seek help for themselves or a family member when we don’t even provide them the rudimentary tools to do so. We must begin now.”

He’s right.

Society is more informed today. But I knew nothing of mental health issues, not in an educated way, until I was well out of college and proceeding with life as an adult.

Yet growing up, I knew girlfriends who were anorexic, friends who were depressed and some who were self-medicating with marijuana and alcohol. None of the behaviors was understood by my younger self to be linked to mental health. That shocks me now, but it was true.

Think about how far apart caring for our mental health stands from physical health. Infants receive “well-baby” checkups from their first breath outside their mothers, and they’re checked even earlier with prenatal exams.

But consider how differently mental health is addressed, if at all.

Here is a statistic from the letter that ought to stop people cold: “Only a third of those with moderate mental illness, two-thirds of those with severe illness and less than one-tenth of persons with a substance use disorder ever receive any care.”

The sentence reads “any care.” Don’t assume cures.

So if only a fragment of the people who need help receive anything, the impact on society is tremendous. It affects productivity at work, people’s ability to parent — indeed, to have healthy relationships of any sort.

This is a national failure of health care. And it continues to be under-recognized.