Lea remembers all too well what it was like to be in the midst of depression.
"One of the darkest moments would be realising that I wasn't enjoying what I used to enjoy," the 17-year-old said.
"I was really very much in my own bubble, and I was losing that connection with a lot of my friends."
Although her symptoms started as a child, Lea wasn't diagnosed with depression until she was 15.
Lea said the tipping point was the COVID-19 pandemic.
"I was on my phone a lot," Lea said.
"Classes were online, so you'd spend six hours on the laptop and then after that you'd go on your phone or you'd wake up scrolling and then you would lose those natural habits of sleep.
"I was just scrolling aimlessly and just looking for something to keep me entertained … and almost disassociating with life, in a way."
Depression on the rise among teens
New research from mental health non-profit the Black Dog Institute reveals depression is on the rise among young people, particularly teenagers, and it is connected to increased screen time.
The Black Dog study found just over 15 per cent of adolescents reported symptoms consistent with depression, with high rates of self-harm and suicidal thoughts.
It is worse among teenage girls, with rates of depression more than doubling in the past 14 years.
"There are higher rates of depression in younger people than before and people who have higher symptoms of depression are more likely to use screens," said Aliza Werner-Seidler, a clinical psychologist with the Black Dog Institute.
Dr Werner-Seidler is involved in the Institute's ongoing study following the mental health of more than 6,000 Australian high school students across 134 schools over five years.
While the study found screen time and depression were linked, particularly in teenage girls, Dr Werner-Seidler warned it was too early to conclude that increased screen use actually caused depression in young people.
"We don't know whether young people who experience depression are more likely to be on their phones or screens, or whether spending more time on phones and screens is likely to increase the risk for depression," she said.
The research also found many young adults were lonely and struggling to get the mental health support they needed, despite a 72 per cent increase in the prevalence of depression in the past 14 years.
What's the link between screens and mental health?
Research on the link between screen time, social media and mental health problems in young people has been diverse.
Some studies say there is a connection and others say there is none.
Asad Khan from the University of Queensland led a large global study of more than 570,000 11-15-year-olds that did find a strong link between recreational screen time and mental and physical health problems.
"Now, the scientific community is desperately trying to understand the causal mechanism because there is speculation that the relationship could be two-way," Dr Khan said.
"People using social media are more likely to have some kind of mental disorder. But on the other hand, the kids who are depressed or have some mental condition, they're more likely to use screens."
That research, published last year, used survey data to examine the relationship between young teenagers spending several hours a day playing video games, watching television and scrolling social media, on their physical and mental health.
"It was survey data, so we cannot make any possible inferences that high screen time is causing mental health distress, depression or suicidal tendencies," Dr Khan said.
"The causal link is yet to be determined from our study, but there is a strong suggestion that the kids who have mental health conditions are using more screen time."
But Dr Khan said not all screen time was bad. That is also something Black Dog researchers agreed with.
"Using the internet and digital technologies can actually be a great source of support for young people," Dr Werner-Seidler said.
"For some marginalised communities like the LGBTQI+, they report using the online space as a safe space they can find other young people like themselves."
Shutting off
The Black Dog Institute has called for a range of initiatives to boost youth mental health, including reviewing all new and existing young mental health services to ensure they are effective.
Its report suggests ongoing funding should be tied to efficacy. It would also like a deeper investigation into why girls and young women have higher rates of depression and self-harming, particularly First Nations women.
On top of that, researchers say national guidelines should be developed for evidence-based mental health and wellbeing programs in schools, with a focus on early intervention.
For Lea, getting help when she did has made all the difference.
She said depression was a topic of conversation that was avoided in her family.
"I never knew how to go about it because of the cultural stigmas," Lea said.
"If it wasn't for my [school] adviser, who actually led me in that direction, I don't think I would have received the help that I needed."
Part of that help involved getting into exercise and returning to her favourite hobbies: theatre and drama.
But it also meant cutting down on screen time — she has even gone six months without social media.
She's noticed a positive difference.
"I think my mood was a lot more light, and I wasn't so concerned about how I looked … I was very much just living the moment and I still try and do that now."
