 Depersonalisationderealisation DPDR are distressing symptoms of having a sense of detachment and unreality about oneself DP or the external world DR. Cognitive Behavioural Therapy CBT has been found to be beneficial in treating patients with chronic DPDR. CBT for DPDR includes educating patients about these experiences so they have a better understanding and less fear; teaching ways of coping to help them manage the symptoms better; helping reduce the impact on their day to day functioning; and working together to find less distressing ways of interpreting these experiences. Recent research has highlighted that DPDR symptoms are common in people diagnosed with psychotic disorders, and when present are linked with more severe psychotic symptoms. However, there has been no previous study to ascertain if CBT to target DPDR in psychosis would be effective. This study therefore aims to establish the feasibility of a brief CBT intervention for DPDR in people diagnosed with a psychotic disorder. It is hoped that the CBT will reduce the distress associated with DPDR experiences, with a possibility of reducing psychotic phenomena in addition. The investigators will seek to recruit adults aged 18-70 with a current psychotic symptoms as well as meeting threshold for DPDR disorder. Participants will be randomly assigned to receive six sessions of CBT or to a treatment as usual control. Outcomes will be assessed at baseline and follow-up interview at 10 weeks. 