It would be easy to dismiss worries about such an aesthetic concern as weak. But two models-turned-psychotherapists argue in “Face It,” their new guide for women, that struggling with changing looks can be no less daunting than dealing with a financial loss, a demotion at work or a divorce.

After decades of counseling patients, Dr. Vivian Diller and Dr. Jill Muir-Sukenick say that dread about growing older can spur an existential crisis of sorts. Such dread isn’t about vanity per se, but has more to do with a loss of potential and questioning one’s place in the world. It can lead to depression, alcohol abuse or sleep disorders, they say.

Yet, therapy isn’t usually on the short list of solutions for those bothered by an aesthetic “problem.” A lunchtime laser treatment or a $180 face cream is.

Dr. Diller, 56, and Dr. Muir-Sukenick, 57, are here to tell American women — no matter how stellar their accomplishments — that it’s not superficial to admit that aging is upsetting. They encourage their readers to figure out what’s driving them to have daydreams about a refined face-lift rather than scheduling one.

At a time when cosmetic surgery is increasingly seen as a casual endeavor, and anti-aging injections as inevitable, “Face It” gives women practical steps to parse how they feel about this beauty paradox. “Should women simply grow old naturally, since their looks don’t define them, or should they fight the signs of aging, since beauty and youth are their currency and power?” the authors ask in their book.

The answer isn’t simple , if the 20 years’ worth of patient information that the book draws upon is any indication. (They also surveyed other women, 30 to 65, including models because they sometimes consult for modeling agencies.)

The mandate to not look your age has never been stronger. “We’re talking about a generation of pioneers,” said Dorree Lynn, a psychologist in Washington whose book about sex after 50 is expected to be released in April. “They don’t have role models for the way they are aging.”

Sixty isn’t the new 40. “That’s an outright lie,” Dr. Lynn said. “What is true is 60 is the new 60.”

Admitting that appearance matters can be painful for women who feel “slightly insulted by the fact,” Dr. Diller said. Wasn’t feminism supposed to make promotions and ceiling-shattering the attention getters, not a taut brow?

The book’s most intriguing stories come from patients who are surprised to find themselves mourning their sags and veiny legs. Katherine, who did not use her real name in the book, is a 53-year-old science researcher and mother of three who considered herself in the “More Important Things to Worry About” camp. But when she nixed a beach getaway with her husband because she didn’t feel comfortable in any swimsuit, she was troubled by how much she cared. Belatedly, she came to recognize that her family may have taught her that caring about appearance is superficial, but that she could be a woman of substance who happened to use a retinoid at night or visit a spa on occasion.

This can-do age of aesthetics is particularly stressful because the playing field is no longer equal. A baby boomer is pressured to choose whether her brow will be au naturel or smooth during her later years — a decision her mother did not face. Ann Kearney-Cooke, 54, an expert in body image in Cincinnati, said the message those grandmothers heard as their looks went was insulting: “You’re not going to be pumping out babies anymore — you’re not as much use to society.” But at the very least, the sight of peers with just as many wrinkles was a comfort. They could think we are “all in the same boat,” said Dr. Kearney-Cooke, a psychologist.

The authors of “Face It” point out that today an odd morality creeps into our calculations of what we find acceptable. Ridiculing too-obvious cosmetic surgery is now a great American pastime. A post on Gawker asking why people still get plastic surgery recently garnered more than 400 comments, many sent by e-mail from high soapboxes.

Far more fascinating are the 60-something celebrities the masses anoint for having the courage to grow old “naturally” in the spotlight (gasp!), or at least not avail themselves of all the work available to them. Meryl Streep is one such actress. Helen Mirren is another. We like to imagine they are somehow inoculated against self-doubt.

And so, in January, it was vaguely unsettling to hear that Ms. Mirren has a laissez faire attitude toward cosmetic surgery rather than the staunch just-say-no stance her fans had assumed. On a British morning show, she said, “You go, ‘I don’t want to look at that face anymore,’ and I understand that, absolutely.”

But why does that make her a sellout, Dr. Diller asks. In an interview for this article, the authors said they were not against plastic surgery nor less-invasive efforts to slow time’s march. Choosing an intervention out of fear or unquestioningly is what irked them. Sounding quite laissez-faire herself, Dr. Muir-Sukenick said she prefers that women reflect first, before acting.

Yet, just as both Dr. Diller and Dr. Muir-Sukenick urge women to savor their futures, not their pasts, their modeling headshots keep stalking them like ghosts of Christmases past. They appeared on screen during the authors’ March 11 appearance on the “Today” show, and the two women brought them out after the interview for this article. So, why can’t their 50-something faces — lined with wrinkles — speak for themselves?

As Betty Friedan once said of a woman’s later years, “If you are going to pretend it’s youth, you are going to miss it.”