Facebook and mental wellbeing : a crossover randomised controlled study

To study the effect of reducing Facebook use for two weeks on Objective self-reported mental wellbeing in a student population. : Students at the University of Oxford (n=78) participated in a Methods randomised crossover study which consisted of two consecutive two-week periods of minimised Facebook use, followed by normal Facebook use, or vice-versa. Participants were evaluated after each two-week period using the 14-item Warwick-Edinburgh Mental Well-Being Scale (WEMWBS), and completed questionnaires about their Facebook use. Differences in WEMWBS scores were evaluated using a paired t-test. : Of those enrolled, 57 (73%) students completed the entire study. 93% Results reported reduced Facebook use during the intervention period. When limiting their Facebook use, participants had an average WEMWBS score of 46.0, compared to 43.7 during the control period, equating to a difference of 2.3 points (95% CI: 0.4 to 4.2; p=0.016; Cohen’s d = 0.33). There were no significant differences in dropout between the two groups (p=0.3), or differences in effect when stratifying by gender (p=0.9) or relationship status (p=0.6). : Reducing Facebook use may be an effective intervention for Conclusion improving mental wellbeing in university students. Future studies should examine effects in other participant groups, and use longer follow-up periods. Achim Wolf ( ) Corresponding author: achim.wolf@psych.ox.ac.uk Wolf A. How to cite this article: Facebook and mental wellbeing: a crossover randomised controlled study [version 1; referees: 1 2016, :1311 (doi: ) approved with reservations, 1 not approved] F1000Research 5 10.12688/f1000research.8835.1 © 2016 Wolf A. This is an open access article distributed under the terms of the , which permits Copyright: Creative Commons Attribution Licence unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Data associated with the article are available under the terms of the (CC0 1.0 Public domain dedication). Creative Commons Zero "No rights reserved" data waiver The author(s) declared that no grants were involved in supporting this work. Grant information: Competing interests: No competing interests were disclosed. 09 Jun 2016, :1311 (doi: ) First published: 5 10.12688/f1000research.8835.1 Referee Status:


Introduction
Facebook is the largest online social networking service with around 1.1 billion monthly active users 1 .
Previous work has come to different conclusions on the effects of Facebook on mental wellbeing 2,3 . Despite a growing body of research surrounding the effects and implications of Facebook's popularity 4 , no research has used experimental methods to examine the Facebook and mental wellbeing relationship, and uncertainty around causality remains.
To address this, we have conducted an experimental study using a crossover randomised design. Students at the University of Oxford (n=78) were asked to limit their Facebook use for two weeks and complete questionnaires on their mental wellbeing.

Study design
This study used a crossover design with simple randomisation Eligibility data, informed consent, and questionnaire answers were obtained electronically. To confirm eligibility, students had to register with a valid University of Oxford email address.

Intervention
At the beginning of the intervention period, participants were asked to "restrict [their] Facebook use as much as possible for two weeks" and were told "During this time, please avoid using Facebook, including through mobile phones, tablets, and computers." At the beginning of the control period, participants were told they "can use Facebook as much as [they] want" for two weeks. Participants were sent weekly reminders. Facebook use was measured through self-reporting only.
After each two-week period participants were sent links with questionnaires, and were asked to complete them regardless of whether they had followed the instructions given to them.

Outcomes
The primary outcome is within-individual differences in Warwick-Edinburgh Mental Well-Being Scale (WEMWBS) score between the two periods. WEMWBS is a 14-item measure of positive mental wellbeing which has been validated in UK student populations 5 . Secondary outcomes were stratification by two variables: gender, and relationship status.

Sample size
The sample size of 78 was calculated assuming a power of 0.8, an α of 0.05, a minimal detectable difference in means of 2 points in WEMWBS score, a 20% dropout rate, and a standard error of measurement (SEM) of 2.78 (mean of the five SEMs reported in Maheswaran et al. 6 ).

Randomisation
Participants were randomised on a rolling basis after completing the informed consent form, using the rand() function in Excel 2013 (v.15.0). At randomisation, no data other than the participant's email address had been collected. Participants were not blinded to group allocation.

Statistical methods
The statistical significance of the primary outcome was calculated using a paired t-test. Only participants who completed both sets of questionnaires were entered in this analysis.
In a sensitivity analysis, all observations were entered into a regression analysis using Stata's clustered sandwich estimator (vce(cluster) function) to allow for within-participant correlation in data with repeated observations on individuals 7 , and to minimise missingness.
We present self-reported descriptive statistics on age, gender, relationship status, and whether participants reduced their use during the intervention period.
For secondary outcomes, we stratified analyses by gender (female vs. male) and relationship status (single vs. in a relationship).
All analyses were done in Stata, version 12. Observations were entered according to group allocation, following an intentionto-treat approach. Statistical assumptions for paired t-tests were tested using a histogram of the differences in scores (Assumption of Normality, Supplementary figure 1) and by plotting differences in scores against average scores (Supplementary figure 2).

Participants
At randomisation, 40 participants were allocated to Group AB and 38 to Group BA. Two-thirds of participants were female, 46% were single. There was no significant difference in dropout between Group AB and Group BA (Table 1).
During the intervention period 25/27 (93%) in Group AB and 28/30 (93%) in Group BA reported reduced Facebook usage ('less than usual' or 'much less than usual'). In a sensitivity analysis additionally including those with follow-up at 2 weeks only, the average difference in scores was 2.6 points (95% CI: 0.7 to 4.5, p=0.009).
We found no significant differences in effect by gender or relationship status ( The raw data of the analysis on Facebook and metal wellbeing are provided. The text file contains legends by column.

Discussion
In this crossover randomised study, we analysed the effects of reducing Facebook use on mental wellbeing. This is the first randomised study to look at the relationship between Facebook use and mental wellbeing. We find that participants had an average 2.3 point higher WEMWBS score after being asked to limit their  1 Chi-square of difference in dropout (full vs. half or none) non-significant (p=0.3). 2 Data shown for those with complete follow-up (both 2 and 4 weeks). Facebook use for two weeks. For comparison, a study examining a 12 week web-based cognitive behavioural tool to improve mental wellbeing in the general population found a 2.9 point difference using the same scale 8 . Our study supports the idea that associations reported in a previous study 3 may in fact be causal.
The link between Facebook and mental wellbeing may be related to content perceived to be negative. A focus group found five main Facebook stressors: "managing inappropriate or annoying content, being tethered, lack of privacy and control, social comparison and jealousy, and relationship tension and conflict" 9 . In contrast, a study using Experience Sampling Methods found greater changes in self-esteem through text-based communications (including Facebook) than through face-to-face communication 10 . Differences in findings may be due to individual use patterns and feedback from other users 11 .

Limitations
Limitations include high dropout (possibly due to the lack of compensation) and a short follow-up period. Almost all students reported reduced Facebook use. Nevertheless, results could be affected by expectations, or perception of reduced use rather than actual changes in use.

Conclusion
Reducing Facebook use may be an effective intervention for improving mental wellbeing in university students. Future studies should examine effects in other participant groups, use longer follow-up periods, and consider deception to improve participant blinding.

Data availability
All collected data (excluding email addresses and names) are provided.

Consent
Written informed consent for publication of their details was obtained from all participants.

Competing interests
No competing interests were disclosed.

Grant information
The author(s) declared that no grants were involved in supporting this work.