Hence, the investigators' next step is to test the efficacy of CARMS in the context of NHS mental health services and also to test whether the underlying psychological mechanisms on which CARMS is based are correct. The investigators will test CARMS using a medium sized randomised controlled trial (RCT), with two arms of CARMS plus treatment as usual versus just treatment as usual. The investigators will use both quantitative and qualitative methods and analyses to assess CARMS.