Previous research has found links between Facebook use and mental wellbeing. However, this research was purely observational, and has been unable to answer the important question: Does Facebook use affect mental well-being, does mental well-being affect Facebook use, or is there no causal relationship between these two factors?

For this study we plan to recruit at least 78 male and female volunteers from the University of Oxford student population.

Each volunteer will be randomly assigned to one of two groups. Both groups will go through the same two week intervals, but in different orders.

• Volunteers in Group A will first be asked to restrict their Facebook use as much as possible for two weeks, and then use it as they want for two weeks.
• Volunteers in Group B will first be using Facebook as they want for two weeks, and then restrict their Facebook use for two weeks.

During the restricted period, we ask you to limit your Facebook use as much as possible, including through mobile phones, tablets, and computers.

Both groups will be asked to complete online questionnaires on their mental wellbeing, and Facebook use. Questionnaires will need to be completed twice i.e. after each two week interval.

This study has been reviewed by, and received ethics clearance through, the University of Oxford Central University Research Ethics Committee.

You can take part if you are:

• Over 18.
• A full-time student at the University of Oxford.
• A daily Facebook user.

You will also need to agree to restrict your Facebook use for two weeks.

This research project is done purely out of scientific curiosity and is not backed by any funding. Therefore, you sadly will not get paid for your time as a volunteer.

You do not have to take part, and you can withdraw from the study at any time without giving a reason and without penalty.

If you decide you would like to take part in this study, you will be asked to complete an online consent form. You will then receive further instructions by email.

Though the questionnaires employed in this experiment have been used previously without any problems, there is a small chance that you might find questions that you would rather not answer. If you would rather not answer any question you can choose to terminate your involvement in the study at any time.

There are no benefits to you taking part, but you will be contributing towards research into mental wellbeing and the use of social media.

The data will be analysed and written up for publication in a scientific journal. The results may also be presented at scientific meetings, or in talks at academic institutions. Results will always be presented in such a way that data from individual volunteers cannot be identified.

This study has been reviewed by, and received ethics clearance through, the Central University Research Ethics Committee (CUREC), University of Oxford.

If you have a concern about any aspect of this project, please speak to Achim Wolf (01865 226201) who will do his best to answer your query. The researcher should acknowledge your concern within 10 working days and give you an indication of how he intends to deal with it. If you remain unhappy or wish to make a formal complaint, please contact the chair of the Research Ethics Committee at the University of Oxford (Chair, Medical Sciences Inter-Divisional Research Ethics Committee; Email: ethics@medsci.ox.ac.uk; Address: Research Services, University of Oxford, Wellington Square, Oxford OX1 2JD). The chair will seek to resolve the matter in a reasonably expeditious manner.

Please feel free to contact us at achim.wolf@psych.ox.ac.uk.