Patient data from clinical records are increasingly recognised as a valuable resource and a number of global initiatives exist to promote and enable the sharing of data. However, some mental health service-users have expressed concerns about the use of their data by services, but these have not been explored in depth and the acceptable limits of data sharing remain unclear. The purpose of the study is to present different approaches to data sharing, with examples taken from across the world, varying in levels of anonymity and amounts of data stored and shared, with a view to extracting relevant principles directly from mental health service users. The primary objective of this study is to understand from service-users the limits of acceptable pseudonymised data sharing and data collection methods. This will inform the wider scientific community about any emerging questions and issues on pseudonymised clinical data sharing. We aim to explore the level of benefit service-users would accept, in exchange for the level of pseudonymised data they provide. Additionally, this study aims to investigate what service-users consider "identifiable" data, for example whether they consider demographic or location data or purely their real name to be identifiable. This study will ensure service-user views are an integral contribution to future pseudonymised data sharing systems, maximising applicability and acceptability. This study will use qualitative methods, in the form of focus groups, to gather service-user views. Focus groups will consider what participants believe to be identifiable data, who should get access, how should individuals and/or companies get access, how should data be protected and whether these answers change if pertaining to mental health information. Focus group data will be analysed using thematic analysis. Themes produced will be presented to participants in a second focus group. Participants will be encouraged to expand or change anything.

Inclusion Criteria:

• Individuals who have experience of using mental health services or experienced mental health difficulties in the past.
• Aged 18 and above.
• Able to give informed consent.
• Ability to speak fluent English.

Exclusion Criteria:

• If identified through C4C, participants whose care team specify concerns regarding taking part in the study.
• People in whom significant concerns have been raised relating to risk, where risk refers to the extent to which an individual poses a threat to themselves (e.g. self-harm or suicidal intent).
• Inability to give informed consent, as judged by the clinician responsible for a service user's ongoing care, where applicable.

We want to capture the views of a broad range of service users who have used mental health services or have experienced mental health problems from diverse backgrounds (ethnicity, age and clinical diagnoses).