Recurrence rates for mania and depression in bipolar disorder

are high: around 50% at 1 year and 70% at 4 years. Relapse prevention teaches people to recognise and manage early warning signs of mania and depression, and can increase time to recurrence, reduce the need for hospitalisation and improve functioning. However, previous studies used specialist services, expert therapists or extensive therapy, which are not routinely available in mainstream services such as the UK National Health Service (NHS). This study examined the feasibility of a cluster randomised controlled trial (RCT) of an enhanced form of relapse prevention v. treatment as usual delivered by frontline care staff (care coordinators) in community mental health teams (CMHTs), and collected data to support a meaningful sample size calculation to be made for a phase III trial with a cluster RCT design. Hence a power calculation was not applicable.