Table 2.

Themes and corresponding wellbeing concepts, with supporting quotes from the papers.

Theme	Positive/Negative?	Corresponding wellbeing concepts	Supporting quotes
1) Self-expression and validation	Both	Self-esteem Social support Identity experimentation Social comparison Anxiety and fear of judgement Risky behaviour Self-acceptance Personal development	“When you’re changing your profile picture it’s like, “What are people going to think? What’s going to happen?” Are people going to comment or are they not going to comment?” (Calancie et al., 2017, p.5)“Everyone’s gotta be better than everyone and if you’re not better then you’re nothing” (Singleton et al., 2016, p. 398) “You can look back at all your old photos. . . see how you’ve developed” (Weinstein, 2018, p. 3611)
2) Appearance comparison and body ideals	Negative	Self-esteem Body image Social comparison Eating disorder relapse	“You want to be popular, you want people to like you, you want boys to like you” (Berne et al., 2014, p. 530) “If someone is insecure about their appearance, then people tend to use that. . .it’s a good weapon” (Berne et al., 2014, p. 529) “They have makeup artists, Photoshop, they have work done to them” (Burnette et al., 2017, p. 121)
3) Pressure to stay connected	Negative	Social pressure Social exclusion Emotional detachment Disconnection anxiety Sleep disruption Physical health issues	“Social media is like an online drug”(O’Reilly et al., 2018, p. 608) “Just think about all the things that I wouldn’t see . . .I feel like once you get it, you’re basically stuck” (Calancie et al., 2017, p. 8) “You’re always wondering ‘What’s everyone else doing?.. Should I be up?’ And then yeah- it affects my sleep” (Scott et al., 2019, p. 542)
4) Social engagement and peer support	Positive	Social support Social participation Connection Mental health recovery	“If I wasn’t on social networking sites, I wouldn’t know half the people I know. I definitely feel more confident talking to some people online. . .” (Kennedy & Lynch, 2016, p. 160) “You notice that there’s thousands all across the world in the same boat as you” (Singleton et al., 2016, p. 400) “‘Hundred-happy-day’ challenge. . .every day you took a photo about what made you happy” (O’Reilly et al., 2018, p. 984)
5) Exposure to bullying and harmful content	Negative	Emotional distress Anxiety Suicidal thoughts Self-esteem Lack of control Injustice Social exclusion and threats to belonging Loneliness and isolation	“It’s a dangerous place social media” (O’Reilly, 2020, p. 203) “People take advantage. . .being anonymous. . .target you with loads of rude comments and that can make you feel really insecure” (O’Reilly et al., 2018, p. 607) “If you’re exposed to a lot of stuff about self-harm and mental illness, it might affect you mentally as well” (O’Reilly, 2020, p. 203)