Why it matters: Most people know Instagram can have a negative impact on mental health, especially for teenage girls with body image issues. Even Facebook knows this, as shown by internal research it has carried out over the last three years that it kept secret.

Leaked Facebook documents obtained by the Wall Street Journal show that the social network has spent the last few years examining the effects Instagram has on younger users' mental health. The company has long insisted that social media can positively impact users' state of mind, but its own research appears to contradict those statements.

"We make body image issues worse for one in three teen girls," reads a slide from one internal presentation in 2019. "Thirty-two per cent of teen girls said that when they felt bad about their bodies, Instagram made them feel worse," researchers said in another presentation from March 2020.

"Teens blame Instagram for increases in the rate of anxiety and depression. This reaction was unprompted and consistent across all groups."

The results of a study of teens who had suicidal thoughts found that 13% of British users and 6% of American users could trace their issues back to Instagram. Elsewhere, more than 40% of Instagram users who reported feeling "unattractive" said the feeling began on the app. About a quarter of the teens who reported feeling "not good enough" said the issues started on Instagram.

"Aspects of Instagram exacerbate each other to create a perfect storm," the researchers said.

Studies showing the detrimental effects Instagram has on younger people's mental health have been around for years, but Facebook has played down any link. In March, CEO Mark Zuckerberg, who was reportedly informed of the findings last year, said that social media was more likely to have a positive impact on mental wellbeing.

Defending plans to launch an Instagram for under 13s, Zuckerberg told a congressional committee "I believe the answer is 'yes,'" when asked if the company had researched the app's effect on children.

Senators in August asked Facebook to send its internal findings that showed the impact Instagram has on youth mental health. It sent a six-page letter that did not include any company research.

Facebook recently rolled out the ability to hide the Like count on its platform and Instagram after experimenting with the option for several years. It's hoped that the move will ease the pressure on those people, particularly younger users, who equate social media popularity with self-worth.

Instagram's head of public policy, Karina Newton, responded to the Wall Street Journal report in a blog post. Newton said the story "focuses on a limited set of findings and casts them in a negative light."

"We're exploring ways to prompt them to look at different topics if they're repeatedly looking at this type of content," Newton added. "We're cautiously optimistic that these nudges will help point people towards content that inspires and uplifts them, and to a larger extent, will shift the part of Instagram's culture that focuses on how people look."