NEW YORK (MainStreet) — Growing up is never easy and comes with many daunting challenges. But studies suggest millennials are having a harder time becoming self-sufficient than any other generation in recent history — with college being part of the solution and part of the problem.

According to a study by researchers at the International Institute for Applied Systems Analysis, the numbers of young people around the world failing to transition from childhood to independent adulthood has been growing. More are still living at home with their parents and unable to get long-term, full-time employment.

"Young adults are doing increasingly worse economically in spite of living in wealthy regions of the world," said IIASA population expert Vegard Skirbekk and co-author of the study, in a press release.

Skirbekk and the two other researchers who worked on the study, Warren Sanderson and Marcin Stonawski, dub this "Young Adult Failure to Thrive Syndrome" in the study, which appeared last month in the Finnish Yearbook of Population Research.

They blame global economic and demographic shifts that began in the 1980s, with failure to thrive likely tied to a more globalized labor force and more women entering the workforce. The current generation of young adults is also more educated than their predecessors, putting a glut of workers qualified for more skilled positions into an increasingly tighter labor market.

At the same time, technological advances have opened up opportunities for new positions but rendered many others obsolete, creating a trend toward fewer industrial jobs and more service-sector jobs that are often lower paying and part time.

"Even as economic conditions have improved for some in the population, young people are worse off today than they were 20 years ago," says study co-author Warren Sanderson, an IIASA scholar and professor of economics and history at SUNY Stony Brook.

Failure to thrive syndrome "is most prevalent among those with the least education," says the study, while noting that a college education also doesn't ensure immunity from the syndrome.

This would be the case for 27-year-old Brian. Though he has a bachelor's degree in aviation management, he lives at home with his parents while trying to pay off $230,000 he accrued in student loans.

"The prospect of buying a house, getting another car or starting a family with my incredible girlfriend is pretty much off the table," says Brian, who just started a job that pays about $50,000 a year.

Even with his new position, he doesn't believe he will be able to make enough to live more independently anytime soon.

Still, a study published last month by the Pew Research Center indicated that not going to college causes a greater economic burden than pursuing a degree. It found that college graduates age 25 to 32 who are working full time earn an average of $17,500 more annually than those with only a high school diploma. Millennials with college degrees were also 7% more likely to be employed full-time.

Attitudes toward work among the 2,002 millennials surveyed by Pew were greatly dependent on whether they held a degree, with 86% of college graduates calling their current job a steppingstone to a career, as opposed to 57% of those with only a high school diploma. Most of the survey participants (72%) with a bachelor's degree believe their college education has already paid off, and from analyzing Census data the Pew Center found that 22% of millennials with only a high school diploma are living in poverty, compared with 6% of those with a bachelor's degree. Overall, millennials with a college education were generally less likely to still be living at home and more likely to be married.

Yet even with all of economic benefits of a college education, millennials are faring far worse than previous generations. For instance, even though the median annual earnings of 25- to 32-year-olds with a college degree has increased by $7,000 since 1965, millennials are not earning more than earlier generations of young adults — with or without a degree.

"The Great Recession and the subsequent slow recovery hit the millennial generation particularly hard. Neither college graduates nor those with less education were spared," says the Pew Social Trends website. "On some key measures such as the percentage who are unemployed or the share living in poverty, this generation of college-educated adults is faring worse than Gen Xers, baby boomers or members of the silent generation when they were in their mid-20s and early 30s."

Of course, not everyone is buying that a college education is worth putting oneself into tens (or in some cases, hundreds) of thousands of dollars of student loan debt. Some critics suggest that the economic benefits of a college degree are either undermined or altogether canceled out by crippling debt.

"There's not a worse decision a young American can make than attending college sans parental money or massive scholarship," wrote Matthew Saccarro for Salon last month. "You're paying for nothing that you can't get elsewhere for less money or free, save for the piece of paper with a con man's signature on it."

Saccarro's sentiment resonates with 26-year-old Steve. Even though Steve would like to get married and have kids in the not-so-distant future, he feels he will never be able to afford it due to $140,000 in student loan debt (which started as $60,000 but skyrocketed with fees and capitalized interest over the past several years).

"My degree hasn't helped me in the slightest to get any reasonably well-paying job, nor was it needed to get the non-union labor and minimum-wage retail jobs I've had to work since graduating," says Steve, who has a degree in media arts and is trying to get his photography business off the ground. "I don't go out to socialize or date because either I can't afford it or I'm embarrassed that I still live with my parents."

— By Laura Kiesel