(CBS)- Anxiety is rising for America's youth, but at a faster rate among girls than boys, according to psychologist and CBS News contributor Lisa Damour.
"There are unique pressures that girls face. They worry more about school. They worry more about disappointing adults. They are achieving unbelievable things these days, and yet, they know they are still judged heavily on how they look," Damour said Tuesday on "CBS This Morning."
A 2017 study in BMC Psychiatry found 31 percent of girls and young women have symptoms of self-reported anxiety compared to 13 percent of boys and young men.
Based on her research and clinical experience, Damour addresses the issue in her new book, "Under Pressure: Confronting the Epidemic of Stress and Anxiety in Girls."
The child development expert and mother of two daughters said parents have to be mindful that the messages they sent to girls can be powerful.
"We can make anxiety and stress much worse for our daughters or much better. When they are very stressed and anxious, sometimes, we then get stressed and anxious," she said.
She gave the example of a toddler skinning her knee.
"The first thing they do, they look at their knee and then they look at your face. And if you are calm, even if you're panicking inside, they're OK. And if you are panicking, they are panicking. So our job is to take that up into later childhood and adolescence, and when they are panicking, we stay calm and we say it's going to be OK. We'll figure this out," Damour said.
She also advised validation works better than reassurance.
"So when girls are having a hard time, my favorite two words are 'stinks' and 'handle.' So we say, 'You know what, that stinks. That does, it stinks.' And then we say, 'I think it's in the category of what you can handle and I'm here to help you handle it,'" Damour said.
As for friendships among young girls, she said less could be more.
"We think it's great to have a whole bunch of friends but when you look at it, numbers bring drama. There's no getting around it. And the reason for that is that it is impossible to get five human beings of any age who like one other equally, and yet, seventh graders attempt this," Damour said.
That doesn't mean you have to "fire" certain friends from social circles, she added.
"The least stressed kids have one or two really good friends because it's reliable and the drama is low," she said, adding, "It's just to recognize that the stress is sort of built into how they arrange themselves. It's not that anyone's being unusually catty or difficult."
Damour also warned parents that even if they themselves don't focus on how the girl looks, "they're up against a culture that sends a very powerful message" – one that is obsessed with beauty.
"What we have to remember is, we are focusing on the most superficial aspect of that girl and the one over which she has the least control," Damour said. "So when we are talking about girls' looks, we are not talking about how creative and clever and interesting they are. And I think about it almost like a zero sum game: We can talk about one, or we can talk about the other, and we talk about the first one a lot."