Dear Grandparenting: I pay equal attention these days to what it’s doing outside as the weather inside our house. It gets right stormy in these parts when my granddaughters go into of their funks. They mope around like they are living under a black cloud, snapping at everyone.

It comes on without warning. Like they’ll get up from dinner after being nice and everything and then 30 minutes later, WHAM BAM! I get blindsided by a crabby granddaughter going off on some crazy tangent, crying about cats or a person they’ve never met who lives in Finland. Then they might stay depressed for a week. It’s a mystery to me, but I bet the Internet is involved because that’s everything to those girls.

They have nothing to cry about. When I compare what my life was like at their age, my granddaughters have it made. Mommy and Daddy fight but they clean up all the messes. Wait until they hit the real world and are unlucky at love or jobless and broke. Maybe my late wife could help explain this, but she’s gone now. Any ideas? Monte Bradshaw, Atlanta, Georgia

Dear Monte: The sexes have different coping styles, right down to adolescence. Grandsons nurse their wounds privately and work through it, sometimes resorting to drugs or alcohol. Granddaughters are inclined to share and talk about it, often utilizing Internet-enabled social media tools like Facebook.

But in some instances, these social networks cause members of the group to imitate and behave like others, even internalize and take on their troubles. To those who study group dynamics, it’s a “social contagion,” something catchy that’s going around.

For grandchildren who measure their quality of life by the content of a stream of written and video group messages, attitudes can turn on a time. Prolonged collective rumination over some perceived misfortune might produce depression and delinquency. According to analyses of social network communications, youngsters swept up in social contagions are more susceptible to issues with obesity, unhealthy body image and low expectations.

Insecure or emotionally immature grandchildren and those who have problems making friends or are alienated from parents and siblings appear at greatest risk for catching what’s going around. We’d bet that instilling them with confidence and independence is the best antidote.

GRAND REMARK OF THE WEEK

Deke, from Reading, Pennsylvania, reports that grandson Christopher, 7, successfully completed his first sleepover while his parents were out of town.

Christopher had some anxious moments at first. “Is it OK to laugh?” he asked when Deke opened the door. “The last thing Mommy told me was no bedroom or bathroom humor around Grandma, whatever that means. She talked so fast I might have forgotten something. Will I get in trouble in the kitchen too?”