Out of the closet, all you mothers who still feel a bit guilty because you didn't mourn when your last child left home. "Empty nest" syndrome, it turns out, causes a sigh all right, but for most, it's one of relief, not sorrow.

In the past decade or so, some brave women have publicly acknowledged the joys of having house and spouse to themselves, not to mention time to renew or sharpen skills and take on career -- rather than family -- responsibilities. Even the psychiatric community has accepted for at least a decade the notion that the once popular diagnosis of "involutional melancholia," which purported to describe the empty-nest depression that occurred around the time of menopause, did not in fact exist.

"It was more a perception in people's minds," says Ellen McGrath, a New York psychologist. "I think this was a product of male MDs" who held a very traditional, Freudian view of women.

Although the disorder was dropped from psychiatry's diagnostic manual in 1980, "the problem is that the public hasn't caught on yet," says Carol Nadelson of Boston, former president of the American Psychiatric Association and an expert in the psychology of women.

Nadelson and others say they hope that the release earlier this month of a report on women and depression by the American Psychological Association will permanently explode the myths of menopausal and empty-nest depression.

Despite a finding by the psychological association task force that women suffer two to five times as much depression as men, neither menopause nor the departure of children was cited as a major cause. Cultural factors such as poverty, unhappy marriage and number of young children at home were far more significant than female biology, according to the task force report.

The cherished belief in the empty-nest syndrome represented "real cultural bias on the part of the mostly male therapists," says McGrath, who was senior editor of the association report. "In our culture, they were basically saying that a woman's worth decreases as she ages and loses her youthful physical appearance . . . and that if women are not producing children and taking care of them as their primary task, their value plummets."

The theory was fueled by women who sought professional help for difficulty with symptoms of menopause. As the APA report noted, those women provided most of the information about menopause, "helping to create the stereotype."

About 5 percent of women may suffer serious depression linked to menopause, but research has indicated that depressed women are twice as likely to report such symptoms as hot flashes to their physicians. It may be that depression causes menopausal problems rather than the reverse.

In a review of the literature conducted in the mid-1980s, Nadelson found that women who experienced the greatest stress at menopause were those who had relied on their mothering role as the prime or sole source of status and self-esteem.

The late anthropologist Margaret Mead, who married several times and did some of her best work while she was in her sixties and seventies, used to refer to "PMZ" -- her acronym for "post-menopausal zest" -- a much more common occurrence, says McGrath.

In a paper entitled "Women in the Middle," presented at the recent annual meeting of the American Psychological Association, McGrath cited a series of cultural issues that have affected women and that are not always considered in psychological diagnoses: Today's middle-aged women grew up in an era when achievement and careers belonged to brothers and fathers, not mothers, sisters or themselves. "We are a group born with a traditional past and a 'liberated' present and future," she says. Women tend to be poorer than men, sometimes because they earn less, at other times because of divorce. A 1983 study published in the Journal of Aging found that a woman's standard of living falls by 73 percent while a man's increases by 42 percent in the first year after a divorce. American culture still sees men as maturing and "becoming wiser" as they age while, McGrath notes, "women simply get old."

Researchers did find that some transient depression may occur at middle age. Some women suffer terribly from hot flashes and other physiological symptoms of hormone deficiency but, because of the lack of long-term research on women's health, are confronted with a mass of contradictions surrounding the issue of estrogen replacement. They are told that estrogen may prevent osteoporosis and may protect against heart disease but that it also may cause breast cancer and probably does cause endometrial cancer. Yet, McGrath points out, women are expected to make these decisions with very little guidance from the experts.

Women who have devoted their lives to their families probably will experience some temporary loss when the nest empties. Therapists have found, however, that this is often more the recognition of the end of one phase of life and the beginning of another. This feeling of sadness may last a few weeks, but rarely does it blossom into full-fledged clinical depression in women who have not had problems with depression earlier in their lives.

But both McGrath and Nadelson note that fewer women reach this stage of life with no resources other than their families. Economics alone has dictated that many women work. In addition, Nadelson, the mother of two adult children who have sporadically lived at home, observes, the worsening economy has brought back to the nest many who had flown, not always to their mothers' unalloyed delight.

"What you hear all over is people saying that they're glad the kids are coming home for Christmas, but isn't that vacation awfully long?" Nadelson says.

Living with other adults in the same house is very different from living with little children, and by the time they're ready to leave, she says, they're in a different stage of life, as are their mothers.

None of this means that the mother who is less wretched than relieved at the departure of her children is not concerned and no longer worries about them. It just means she has her own agenda as well, whether it is earning a college or graduate degree for which she never had time, devoting more hours to a club or civic group or advancing a career that took second place to a family.

Interestingly, Nadelson says, if there is an empty-nest syndrome, it is most prevalent among those who did not stay home and feel as though they spent too little time with their children.

Not all of them are women.

"Recently, we've seen it a lot in fathers," says Nadelson, "men who weren't around much when the kids were growing up. Now they're retiring, and they have time and suddenly the kids aren't there anymore."