APPENDIX.

Items and Descriptives for the Negative Affective Reactions to Social Media (NARSM)

Instructions for the measure: When I use Social Media (such as Snapchat, Instagram, Facebook, Twitter, or YouTube) and see pictures or posts that my friends and acquaintances have posted, I often:
Items	Mean (SD)	Corrected item-total correlation
1. Think that many people have a better life than me	3.41 (1.60)	.56
2. Get very upset or hurt	2.25 (1.51)	.53
3. Think it’s fun to see other people have such a good time (Reversed)	5.06 (1.42)	.22
4. Think that many people are happier than me	3.59 (1.85)	.65
5. Feel badly about my life	2.23 (1.54)	.68
6. Feel lonely or like I don’t have enough friends	2.86 (1.99)	.73
7. Think that life is fair (Reversed)	3.83 (1.66)	.03
8. Feel angry or jealous	2.47 (1.62)	.66
9. Wish I was invited to more events or social gatherings	3.89 (2.05)	.57
10. Feel sad or depressed	2.23 (1.60)	.70
11. Feel left out	2.96 (1.91)	.73
12. Feel happy that my friends are having a good time (Reversed)	5.23 (1.54)	.19

Note. The items were answered on a 7-point scale, where 1 = strongly disagree, 4 = neutral or neither agree or disagree, and 7 = strongly agree.