Gen Z has seen their life satisfaction plummet compared to their Millennial predecessors a generation ago, with less than half now describing their lives as “thriving,” down from nearly half of young people in 2008.

More than a quarter (27%) of adults aged 18 to 29 also reported that they are being treated for depression, up by 11 points since 2019, according to the new Life Evaluation Index poll from Gallup.

Many young adults described themselves as drifting away from friends and partners and experiencing less joy — while less than a third said they had reached most of their goals for the last year.

“Gen Z has had constant access to their smart phones and social media, plus a global pandemic plus financial stressors like housing that no other generation has had,” Dr. Katrina Furey, MD, a Connecticut-based psychiatrist told The Post.

“The social isolation of COVID-19 during their formative developmental years for sure has left a lasting impact,” she said.

“Depression and loneliness can really tie into your social connections.”

“And I do hear a lot of distress from that generation about their future,” she said.

Only 44% of young adults described themselves as “thriving,” compared to 64% of the same age group back in 2010, the survey found.

Most of that decline in positivity has happened since 2019, with a major drop occurring during the COVID-19 pandemic, according to polling.

While the percentage of “thriving” young adults declined gradually during the 2010s from 64% to 57% in 2019, by 2020, that figure had dropped to 39%.

The “thriving” percentage rebounded partially to just over half (51%) by 2023, before falling again.

Young adults were down in every key measure for positivity, with less than half (47%) saying their relationship with their spouse, partner, or closest friend was stronger than ever, down from 65% in 2019.

Only 64% of Gen Zers said they experienced joy yesterday, down 17 percentage points from young adults in 2019. Only 28% said they had felt active and productive every day in the past week, down 16 percentage points.

“They are also the first generation that has really grown up online. Research has shown higher rates of eating disorders and depression linked to social media, and I can’t imagine that’s not part of it for Gen Z,” Furey, founder of Repro Psych Academy, said.

Just a third of Gen Zers said they had a leader in their life who made them enthusiastic about the future, down from 47% of young adults who said they had someone to idolize in 2019.

Only 41% said that compared to the people in their life, they were satisfied with their standard of living, down 14 percentage points since 2019.

Less than a third (31%) of young adults said they had reached most of their goals in the past 12 months, down from 44%.

While Gen Z were the least positive generation, they were far from the only ones feeling glum.

Millennials showed a similar decline, with just 45% of those aged between 30-44 “thriving.”

Gen X positivity hasn’t dropped as much as younger groups, but the 46% of those aged 45 to 64 now thriving matches their generation’s low from 2008 during the height of the Great Recession.

The only generation that has higher life evaluations now than in 2008 is Baby Boomers, with the percentage of those aged 65 and older who are “thriving” rising steadily from 38% in 2008 to 53% in 2026, matching their record high of 2021.