A little smug self-absorption might be a time-honored trait of at least some subsets of the under-30 crowd.

But over the past few decades the prevailing disposition among college students – today labeled Generation Y or Millennials – has slid into full-blown narcissism, according to a study released this week.

The "all about me" shift means much more than lots of traffic at self-revelatory websites such as YouTube and Facebook. It points, says the study's author, to a generation's lack of empathy, its inability to form relationships – and worse.

"Research shows [narcissists] are aggressive when they have been insulted or threatened," says Jean Twenge, a psychology professor at San Diego State University and lead author of the report, called "Egos Inflating Over Time." "They tend to have problems with impulse control, so that means they're more likely to, for example, be pathological gamblers [or] commit white-collar crimes."

For some, the study validates their suspicions of educational and parenting techniques that put undue emphasis on the positive: tot-level self-esteem boosterism, luxury-as-necessity entitlement, and what one calls "instant fame-ification."

"I can't imagine you can do a study on Gen-X, Gen-Y, Gen-Z and not have the takeaway be an inappropriate application of self-esteem," says James Twitchell, an English professor at the University of Florida, Gainesville, and an author of books on cultural shifts in the US. The trend is apparent even in student grading. "Grade inflation is just [another] adaptation of Lake Wobegon to everyday life. Everyone is 'above average,' " he says.

But others – including proponents of the self-esteem movement, workforce experts, and students invited to assess the study's unflattering mirror – take issue with the apparent lack of nuance in the study, still being reviewed for publication in a scholarly journal.

These young adults are "hard to define," says Jody Turner of the Los Angeles business-strategy consultancy CultureofFuture.com. "Most kids coming out of college are looking at ways of contributing but not giving up their material goals," she says, and finding ways to do that by marrying Gen-X creativity with the "community desire" of other generations.

"You do have to be careful. There's a lot of conflicting evidence," says Christina Hoff Sommers, a resident scholar at the American Enterprise Institute in Washington who has studied youths and morality. "Millennials are also among the most hardworking and least inclined to self-destructive behavior," she says. "They've behaved better than the Gen-Xers or the baby boomers.... They're closer to their parents than [were] previous generations."

Still, according to the study, 30 percent more college students showed "elevated narcissism" in 2006 compared with 1982. Over 25 years, researchers have posed a series of "narcissistic personality inventory" questions, each with two possible answers, to more than 16,000 students, with the latest survey conducted last year.

That makes "current college students more narcissistic than baby boomers and Gen-Xers," its authors conclude. (Data points between 1982 and 1990 are few, says Professor Twenge, also the author of "Generation Me.")

That quality can be amplified when school's out.

"Gen-Y is the most difficult workforce I've ever encountered, because part of them are greatest-generation great and the other part are so self-indulgent as to be genuinely offensive to know, let alone supervise," says Marian Salzman, a trendspotter and senior vice president at JWT, the global advertising agency.

Millennials themselves don't completely reject the new label. But they offer some modifications.

"I know people who are attention- seekers and only think about themselves," writes Jessica Riggin, a sophomore at California State University, Monterey Bay, in Seaside, Calif. In an e-mail, she attributes the behavior mainly to overconsumption of low-brow media, which leads to crass celebrity-emulation among many of her peers. She doesn't buy in. "I don't care who Anna Nicole's baby's father is," she writes, "and I don't care who's admitting themself [sic] into rehab."

Ms. Riggin prefers another kind of social participation: She volunteers at the Marine Mammal Center near her school and at the Monterey Bay Aquarium.

"We live in a society that emphasizes the power of the individual," notes Zach Samson, a senior studying journalism at Northwestern University near Chicago. "So it is very easy to see why my generation would be considered so narcissistic." Growing up, he was told he was "special," he says, and that he could accomplish anything he worked for (and he ended up interning with Oxfam, the antihunger group, last year in Thailand).

"But my parents were not emphasizing that I was this grand person who was better than everyone else," Mr. Samson says, "just that I was unique, as was every other person."

That kind of parenting is in line with the positive aspects of the self-esteem movement – success tied to relationships and the development of empathy, the inverse of narcissism, says Janis Keyser, coauthor of "Becoming the Parent You Want to Be," the parenting bible of the '90s.

Some of the Twenge-study answers meant to indicate narcissism ("I like to be the center of attention," for example) actually strike Ms. Keyser as "signals of somebody who is feeling insecure."

Self-esteem today is often approached in terms of "personal worth" – feeling good about oneself, says Chris Mruk, professor of psychology at Bowling Green State University in Ohio. But feeling good about oneself without demonstrating competence, he adds, does lead to narcissism.

"Our society tends right now to be a little more lopsided toward the feeling-good end, the individual end," says Professor Mruk. "You really do need to have both competence and worthiness. The middle point is where the balance would be," he says, "and where well-being would occur, both socially and individually."