As part of a five-part, 3-D exhibit on mental illness she created for her high school senior project, Olivia Stewart crafted hard wire protruding from a red velvet heart wrapped in a cement pair of lungs.

She called it "Anxiety."

When Stewart was a freshman at ThunderRidge High School in Highlands Ranch, her best friend attempted suicide. That crisis triggered a series of mental health challenges that followed Stewart through high school.

“My attendance was ridiculous because of how suffocating high school had become,” said Stewart, an 18-year-old with curly, long brown hair and a contagious smile who graduated from ThunderRidge last May. “There was an immense weight — from grades to friends.”

But anxiety was the constant, a presence that made her breathless, forgetful, too hungry or not hungry at all.

“There's such a stigma that it is in your head,” she said.

It's not: Anxiety, an emotion characterized by feelings of worry or unease, is increasingly present in many young people's lives, say school counselors and mental health experts who work with teens.

According to a 2010 study funded in part by the National Institute of Mental Health, 25.1 percent of 13- to 18-year-olds experienced anxiety at some point in their lives and 5.1 percent of 13- to 18-year-olds experienced severe anxiety, such as panic or social anxiety disorders.

Statistics about whether anxiety among young people is growing are challenging to gather, experts say, because it is difficult to measure the occasional feeling of anxiety compared to a more persistent anxiety or an anxiety disorder, which interfere with daily life functions.

But what is certain, mental health counselors, parents and students say, is that the barrage of social media and technology is making teens more anxious.

“Our world is very anxiety-provoking," said Lauren Kerstein, a licensed clinical social worker in Greenwood Village. "And high schoolers are being exposed to it in a much different way because of social media and being able to access information 24/7."

That, combined with common factors such as schoolwork, friends and sports, can create a challenging environment for many teens.

Heather Golden, a counselor at Castle View High School in Castle Rock, sees about 80 to 100 students a week, many of whom are dealing with a wide spectrum of issues.

“It can be grades, tests — any bump in the road — a conflict with peer or parent,” she said. “It doesn't have to be anything specific, they just feel very anxious.”

But anxiety doesn't have to be a debilitating emotion.

Teenagers need to understand that everyone experiences anxiety, mental health experts say. What's important is learning how to manage it.

“It's a motivator, it gives us energy and keeps us safe,” said Ali Schroer, a licensed clinical social worker at Children's Hospital Colorado Therapy Care Center in Highlands Ranch. “When that alarm bell goes off more than it should, we need to figure out how to quiet it.”

Keeping up with school

Grades, in particular, are a source of anxiety for Mountain Vista High School senior Justin Chang. He said he experienced constant stress when high school started because he wasn't ready for the transition.

“I couldn't get everything done on time, which discouraged me,” he said.

Chang, who describes himself as a procrastinator, feels anxious sitting and listening to lectures. He also starts to feel panicked when he has too many projects or assignments.

“I try to find ways to avoid it rather than dealing with it, which makes me more anxious,” he said. “It's a bad cycle.”

He sometimes worries about getting into college — a stressor that retired Mountain Vista High School counselor Cathy Mumper saw all too often.

“There is high academic pressure,” said Mumper,who retired in 2011 after 15 years as a counselor and 31 years in education. “There's fear of the whole academic piece and of letting parents down.”

Desiree Messer, an athletic and well-spoken senior at Castle View High School, worries about life after high school to the extent that it is difficult for her to focus on the present.

“I'm more scared of what my schooling will do for my future than of what it is now,” she said. “I worry about where school is leading me and what I will do.”

Messer was on the school's dance team for three years. She quit the sport because it added unneeded stress, she said. She has applied to six out-of-state colleges.

Students, Mumper said, have an expectation they need to be perfect.

Amber Schweitzer, a teacher at Castle View High School, agreed.

“We see test anxiety — feeling like they aren't prepared or good enough,” she said.

Schweitzer, who teaches yoga and health classes at Castle View, said she sees anxiety stem from teenage life in general.

“In every one of my classes," she said, "I have kids who are afraid to speak to the class because they are afraid of being judged.”

The effects of social media

A new trigger of anxiety in youth — but among the biggest, research shows — is social media.

Messer has felt the pressure. She feels like she has to have weekend plans or else she is missing out because of posts she reads from friends and schoolmates.

“It almost makes me feel guilty for not being social all the time,” she said. “I think, 'What am I going to do? How am I going to stay busy?'”

According to two 2015 studies conducted by Pew Research Center, 92 percent of teens go online daily, 24 percent go online almost constantly and 90 percent use social media, a significantly higher number than the 12 percent who used social media in 2005.

The constant flow of information can be distressing and challenging, Pew reported in a 2015 study on the relationship between digital technology uses and psychological stress.

“There are more possibilities for interruptions and distractions,” the study said. “It is easier to track what friends, frenemies and foes are doing and to monitor raises (sic) and falls in status on a near-constant basis.”

A Highlands Ranch parent, who wanted her name withheld for privacy reasons, witnessed the effect of social media on her 15-year-old son. A student posted a negative message about her son on Twitter, who then saw it get more than 40 likes.

“It was like stabbing him over and over in the gut,” his mother said.

There's a “compare-and-despair” factor induced by scanning through photos and posts of other peoples' lives, the website Anxiety.org reports. There's also “fear of missing out” when a social media user sees pictures of a party or event to which he or she was not invited.

Taylor Wells, an eighth-grader at Ranch View Middle School in Highlands Ranch who is active on Snapchat and Instagram, said the social media sites often do spur those negative reactions.

“It causes jealousy,” she said, “not feeling pretty enough.”

As mental health experts on Anxiety.org said: “Social media has become an anxiety-provoking factor.”

“If they don't get the amount of likes, they take it personally,” agreed Schroer, the Children's Hospital social worker who works with children and teens ages 3 to 18. “All of these internal messages go rampant.”

Coping with anxiety

Because anxiety is a constant in life, mental health experts say, the key to managing it successfully is knowing the triggers and learning coping skills.

A critical part of dealing with the emotion, Mumper said, is recognizing that it is there.

“It takes courage to acknowledge feelings,” she said.

Kerstein said it is important for teenagers to recognize they have control over their emotions.

“We don't have control over a lot of the environmental factors but we do have control over emotions,” she said. “Once a person believes that — as painful as it is — they can begin to take steps towards making a difference.”

That difference could be in simply talking to someone about a feeling. A confidant can come in many forms — a teacher, a friend, a school counselor, a family member.

“It's very easy to isolate — to think you're the only one and believe that nothing will change,” Kerstein said. “But there are people out there who can help that student feel comfortable in their own skin.”

That was the case for Olivia Stewart.

“You have to acknowledge a thought or emotion and face it — either on your own or by talking to another person,” she said. “If you push it back, it becomes an overwhelming weight.”

Schroer encourages a teen to identify the triggers of his or her anxiety, which may be studying for a test, planning for prom, leaving for college or engaging in a social interaction.

“Anxiety is predictable,” she said. “If you know the triggers, you can plan for them.”

She also encourages a student struggling with anxiety to acknowledge one good thing about himself or herself in moments of heightened stress because, she said, teens have the most criticism of themselves.

Another way to alleviate anxiety is to connect interpersonally, which could mean joining a club or starting a sport.

Chang finds peace in practicing yoga and swimming. He plays the ukulele on study breaks rather than picking up his phone or checking social media, which he said tend to add to his procrastination.

“When I start feeling anxious,” he said, “it helps to take deep breaths and have something to focus on — it keeps my mind distracted.”

Above all, it's important for teenagers to know they are not alone in dealing with anxiety.

“We need to find ways to make it through," Schroer said, "rather than finding ways to make it go away."

For Stewart, making it through included producing her senior project, which she viewed as a way to educate people on mental illness. Besides anxiety, the other pieces of the installation depicted self-harm, depression, eating disorders and suicide. Stewart said she experienced most of those.

Stewart still struggles with anxiety and depression, though no one would know from her calm and easygoing demeanor. She decided to postpone college for a year to take care of her mental health.

These days, Stewart is doing data entry for her mother's business and searching for a second job. She's galvanized by politics and has been attending Trump protests in downtown Denver. She sees herself being involved in many outreach organizations in her future.

With all that she's been through, Stewart knows she wants to someday help people who have walked in her shoes.

“It's created a strength," she said, "and it's created an insight that I can use to help other people."

As part of a five-part, 3-D exhibit on mental illness she created for her high school senior project, Olivia Stewart crafted hard wire protruding from a red velvet heart wrapped in a cement pair of lungs.