Personalised care involves shared decision making (SDM) across all levels including choice in medication. However, there are a number of barriers which prevent its effective implementation in routine mental health settings. Therefore, we undertook a study to benchmark current practice across clinical services of a large urban mental health provider. The study formed part of the trust-wide ‘Supported Decision Making in Medication’ Co-Production Project and aims to inform future recommendations in delivering against contemporary best practice, guidance and policy. A survey exploring the views and experiences of service users and prescribers on shared and supported decision-making in medication was carried out in West London NHS Trust. Questionnaires were fully co-designed and co-delivered by a group of health professionals and individuals with lived experience. There were 100 responses from service users and 35 from prescribers. There was some good practice where both parties reported good quality conversations concerning dialogic styles, collaborative process, information provided and range of choice offered. However, prescriber’s perception of their practice was not always mirrored by service user feedback whose experiences often depended upon the prescriber, the time available or the part of the service. Generally, service user experience fell short of the good practice cited by clinicians though there was noticeable variability. Commitment from organizations and increasing understanding from practitioners are vital in transforming SDM from rhetoric into reality. From our findings a further challenge is to ensure that prescribers and service users have the time, information and tools to implement it consistently.