Background
Social media has become a dominant part of daily lives for many, but excessive use may lead to an experience of stress. Only relatively few studies have investigated social media’s influence on mental health.

Aims
We aimed to investigate whether social media use is associated with perceived stress and changes in perceived stress over 18 months.

Methods
The study population consisted of 25,053 adults (mean age 42.8; 62% women) from the SmartSleep Study. Self-reported frequency of social media use, of 10 specific social media platforms, and of perceived stress (the Perceived Stress Scale 4 item) was obtained at baseline and 18-months follow-up (N = 1745). The associations were evaluated at baseline and follow-up using multiple linear regression models adjusted for potential confounders.

Results
Compared to non-use, high social media use (at least every second hour) was associated with a slightly higher perceived stress level at baseline. No association was found between the frequency of social media use and changes in perceived stress during follow-up. Only small differences in these associations were noted across social media platforms.

Conclusions
Further studies are needed to comprehensively explore the relationship between excessive social media use and mental health, recognizing different characteristics across social media platforms.