It’s been 20 years since “Mean Girls” premiered in theaters. A lot has changed since then.

“Mean Girls” was adapted into a musical. That musical was adapted into a movie remake early this year. Tina Fey now has nine Emmys. Amanda Seyfried has one, too. Lindsay Lohan is a mother and Lacey Chabert frequently stars in Hallmark movies.

Flip phones are a thing of the past and nearly every U.S. teenager now has a smartphone. Usher is no longer dominating the charts and MySpace has been replaced by TikTok and Instagram.

Here are 20 ways culture has changed for young people since 2004.

1. Teenagers were happier in 2004

Young people, primarily teenage girls, are experiencing record levels of sadness.

Research from the Centers for Disease Control and Prevention reported that 3 in 5 teen girls claim they felt persistently sad or hopeless in 2021. That is a 60% increase from a decade ago. Mental health in teen boys also suffered a decline, but the data was less significant.

This year’s World Happiness Report noted a considerable decline in happiness levels among young Americans, both male and female. Researchers suspect social media use, the COVID-19 pandemic and political polarization all play a role in tanking happiness levels in young people.

2. ‘Shrek 2′ was the biggest film of the year

The highest-grossing movie of 2004 was “Shrek 2″ ($928 million), followed by “Harry Potter and the Prisoner of Azkaban” ($795 million) and “Spider-Man 2″ ($788 million), per Box Office Mojo.

Though less than halfway through the year, the highest grossing movies of 2024 so far are “Dune: Part Two” ($704 million), “Godzilla x Kong: The New Empire” ($521 million) and “Kung Fu Panda 4″ ($503 million).

Other movies released in 2004 include:

• “The Notebook.”
• “13 Going on 30.”
• "Napoleon Dynamite.”
• “A Cinderella Story.”
• “The Incredibles.”
• “Troy.”
• “The Passion of the Christ.”
• “50 First Dates.”
• “Anchorman.”

3. Young adults were drinking more

Young adults (ages 18-34) in the U.S. are considerably less likely to regularly drink alcohol than then young adults two decades ago, according to Gallup research.

The young adults who report being a regular drinker — consuming alcohol at least once per week — has dropped 67% from reports made between 2001-2003.

“After years when younger adults were the biggest drinkers among age groups, they have grown closer to older adults in their drinking habits, leaving middle-aged adults as today’s leading alcohol consumers,” per Gallup.

4. Usher was the most popular artist

“Yeah” by Usher was the anthem of 2004. The song, which featured Lil Jon and Ludacris, spent three weeks as No. 1 and 10 on the charts, per Billboard. Usher also released “Burn,” “Confessions Part II” and “My Boo” in 2004.

Usher’s heyday may be miles behind in the rearview mirror but he got another day in the sun as this year’s Super Bowl LVIII Halftime Show performer.

“This is a celebration of my legacy. It’s a celebration of my music. It’s a celebration of my passion,” Usher told ET ahead of his Super Bowl performance. “Thirty years ago that journey started and now it’s landed me at this point in my life at the Super Bowl. Lot of songs, lot of moments, lot of dance, lot of energy.”

5. Green Day was the biggest band

Green Day’s “American Idiot” hit the shelves in September 2004 — the album features enduringly popular tracks “Boulevard of Broken Dreams” and “Wake Me Up When September Ends.” It won the band a Grammy for best rock album at the 47th Grammy Awards.

The mainstream punk-rock band still tours and has released nearly a dozen albums in the years since, but few rival “American Idiot.”

6. MySpace was state-of-the-art social media

MySpace dominated the early aughts as one of the world’s most visited websites. At its peak in 2006, MySpace had 29 billion visitors just in the U.S., exceeding traffic on Google, per Tech Report. But the once-leading social media site nosedived in popularity in the wake of sites like Facebook, Instagram, X (Twitter) and now TikTok. A few million people still use MySpace — the site had 6.9 million visits in June 2022 — but traffic to the site has significantly slumped since its 2003 debut.

7. Facebook was Harvard-exclusive

From his Harvard University dorm, Mark Zuckerberg co-launched Facebook on Feb. 4, 2004, per The Chicago Tribune. The site was an online directory intended for his fellow Harvard classmates to connect with each other and social organizations. Less than a week after launching the site, more than 650 Harvard students registered to use it.

“I’m pretty happy with the amount of people that have been to it so far,” Zuckerberg said in an interview with the Harvard Crimson at the time. “The nature of the site is that each user’s experience improves if they can get their friends to join it.”

Two decades and a handful of lawsuits later, Facebook — now part of the Meta empire — dominates the social media universe. Facebook has over 3 billion monthly users, but the once-hip social media platform is now ruled by older adults, per CBS News.

8. Teens spend less time with their friends now

High schoolers are spending considerably less face-to-face time together.

According to the long-running Monitoring the Future project from University of Michigan, the number of U.S. high school seniors who spent in-person time with friends “almost every day” fell from 44% in 2010 to 22% in 2024. Social outings for U.S. eighth graders dropped from roughly 2 1/2 times per week in 2000 to 1 1/1 in 2022.

Researchers suggest social media use, coupled with the impact of the COVID-19 pandemic, has led to these decreases in teen social gatherings.

“Teens are spending a lot more time communicating with each other electronically and a lot less time hanging out with each other face to face,” said Jean Twenge, a professor of psychology at San Diego State University and author of “Generations,” a book about generational differences, per The Hill.

“Going to the mall has gone down. Driving in the car for fun has gone down. Going to the movies has gone down,” she said. “We’re talking about kids who are spending five, six, seven hours a day on social media.”

9. The iPhone didn’t exist yet

The first iPhone was not released until June 2007. Until then, teens relied on iPods for music and, if they were lucky, they got a Motorola Razor (which launched in 2004).

But in 2004, the majority of U.S. teens had no cell phone at all — 45% of teenagers owned a cellphone in 2004, and that number jumped to 71% in 2009, according to Pew Research Center. More than 95% of U.S. teens now have access to a smartphone, 45% of which report to be “almost constantly” online, per Pew Research Center.

10. The Summer Olympics were held in Athens, Greece

The 2004 Summer Olympics — officially titled the Games of the XXVIII Olympiad — were hosted in Athens, Greece.

It was a big year for American swimming. Michael Phelps won six gold medals and fellow swimmer Aaron Peirsol took home three gold. Natalie Coughlin won two gold medals for the women’s swim team.

In 2024, the Summer Olympics are set to be held in Paris, France.

11. Beyoncé won her first solo Grammys

While still performing with Destiny’s Child, Beyoncé tried her luck at a solo project. She released her first solo album, “Dangerously in Love,” in June 2003. The album — which features tracks “Crazy in Love” and “Me, Myself and I” — earned her four Grammys, her first wins and a solo artist.

Beyoncé has raked up 88 Grammy nominations, 32 wins and set the record for most Grammys won by any artist in history, per the Grammy Awards.

This year, Beyoncé swapped her trademark R&B sound for country — though she assures fans it “ain’t a Country album. This is a Beyoncé album.” At 27 tracks, Beyoncé made plenty of room for a broad spectrum of genres. She played around with covers of the Beach Boys’ “Good Vibrations,” The Beatles “Blackbird” and guest appearances from Dolly Parton, Willie Nelson and Miley Cyrus.

12. The last episode of ‘Friends’ came out

The 10th and final season of “Friends” aired on May 6, 2004. “The One Where They Say Goodbye” raked in 52.5 million viewers, making it the fourth most-watched series finale of all time, per The New York Times. It still lives among the most-watched shows of all time, according to IMDB.

Nearly two decades after the series’ concluded, the “Friends” cast came together to mourn Matthew Perry, know for his role as Chandler Bing, who was found dead at his Los Angeles home on Oct. 28, 2023.

13. Tom Brady and the New England Patriots won the Super Bowl

In light of the Patriots’ 2002 Super Bowl win, Tom Brady led his team for a second time in 2004 — winning the event once again. Brady led his teams to win five more Super Bowls, setting a record as the NFL player with the most Super Bowl rings, per NFL. In light of the Patriots’ 2002 Super Bowl win, Tom Brady led his team for a second time in 2004 — winning the event once again. Brady led his teams to win five more Super Bowls, setting a record as the NFL player with the most Super Bowl rings, per NFL.

“Good morning, guys. I’ll get to the point right away. I’m retiring. For good,” he said in 2023, after retiring in 2022 and changing his mind about it only a month later, per NFL. “You only get one super emotional retirement essay, and I used mine up last year. So I really thank you guys so much. To every single one of you for supporting me: My family, my friends, my teammates, my competitors I could go on forever. There’s too many. Thank you guys for allowing me to live my absolute dream. I wouldn’t change a thing. I love you all.”

14. More young people went to college

Fewer young Americans are opting for four-year colleges. The rate of young people going to college has been steadily declining over the past decade, especially among young men. Roughly 1 million fewer young men are enrolling in college than a decade ago.

Alternatively, many Gen Z students are going to trade schools. “Gen Z appears to be weighing the higher cost of college and the guaranteed return on investment in the trades and thousands of young people are skipping college, well aware they are following a generation deep in student loan debt,” reports NewsNation.

15. Prince William and Kate Middleton debuted their relationship

After roughly a year of dating, Prince William and his then-girlfriend Kate Middleton hard launched their relationship during a ski trip in the Swiss slopes. Photographs of the pair were published by The Sun in an article headlined, “Finally, Wills gets a girl.”

The couple were married in April 2011 and have three children together: Prince George, 10, Princess Charlotte, 8, and Prince Louis, 6. Kate dominated headlines last month as the world speculated over her health in light of a “planned abdominal surgery.” She revealed in March that she had been diagnosed with cancer and is currently undergoing chemotherapy.

16. Everyone was wearing ‘Livestrong’ bracelets

You would be hard-pressed in 2004 to find a young person without a yellow, rubber “Livestrong” bracelet adorning their wrist. The fad was fueled by road-racing cyclist Lance Armstrong, who is a cancer survivor and founded Livestrong in 1997. The nonprofit organization continues to advocate for individuals fighting cancer, though Armstrong is no longer associated with it.

Armstrong captured worldwide attention during the early aughts for winning the Tour de France seven consecutive times between 1997 and 2005. He fell from grace when an investigation from the United States Anti-Doping Agency revealed the athlete used performance-enhancing drugs, per Reuters.

The cyclist repeatedly denied doping allegations but did not contest the charges. He has since been stripped of his seven Tour de France titles, per The Associated Press. With that, the Livestrong bracelet trend withered away.

Nowadays, teenagers decorate their wrists with beaded friendship bracelets — a trend driven by Taylor Swift and her ongoing Eras Tour.

17. Lindsay Lohan is a mother

Lindsay Lohan reigned over the early aughts. After a series of public arrests, her career slowed down for roughly a decade. She’s made her way back on screen in Netflix movies such as “Irish Wish” and “Falling for Christmas.”

Now, she’s a mother. In July 2023, Lohan and her husband, Bader Shammas, welcomed a son named Luai, per People.

“I can’t wait to see what the feeling is and what it’s like to just be a mom,” Lohan told Allure ahead of having her son. “Happy tears. That’s just who I am. Though now, it’s probably baby emotion. It’s overwhelming in a good way.”

18. J.Lo and Ben Affleck were engaged

Some things never change.

In November 2002, Jennifer Lopez and Ben Affleck got engaged. After postponing their wedding due to “excessive media attention,” the couple broke off their engagement in early 2004. By the end of the year, Lopez had moved on with Marc Anthony and Affleck started dating Jennifer Garner, per Harper’s Bazaar.

The couple reunited in 2021, got engaged for the second time in 2022 and got married in Las Vegas a few months later. The couple appears to be going strong, despite what the Bennifer memes tell you.

19. Gmail launched

On April 1, 2004, Google launched Gmail. Today, Gmail has more than 1.8 billion active users, per Demand Sage data. The platform has been around two decades, but it looks nearly the same as it did when it was launched.

“I can’t think of another app that has existed so close to its original form for 10 years,” Kevin Fox, who designed Gmail, told Time magazine in 2014. “Someone who had only used Gmail in its first iteration and suddenly used it today would still understand Gmail. They’d know how to use it for virtually everything they’d want to do.”

The man who created Gmail, Paul Buchheit, thinks the platform’s biggest flaw is that, “people have become slaves to email,” he told Time magazine in 2014. “There’s a 24/7 culture, where people expect a response. It doesn’t matter that it’s Saturday at 2 a.m. — people think you’re responding to email,” he added. “It’s not a technical problem. It can’t be solved with a computer algorithm. It’s more of a social problem.”

20. People still watched cable television

There were no streaming platforms — those didn’t take over until Netflix launched its streaming service in 2007. Less than half (48%) of U.S. households still pay for cable television, per Tech Report. As of 2024, 99% of U.S. households subscribe to at least one streaming service, with Netflix, Amazon Prime and Apple TV+ ranking as the most popular, per Forbes. But back in 2004, when cable television still reigned supreme, these were the shows that came out:

• “Lost.”
• “House.”
• “Desperate Housewives.”
• “Shameless.”
• “Veronica Mars.”
• “The 4400.”
• “Deadwood.”
• “Boston Legal.”