The study is a pilot study of Cognitive therapy for people with psychosis who have distressing visual hallucinations. The aim is to evaluate whether this is an acceptable, feasible and effective treatment. This is a pilot study and there is no randomisation to either CBT or treatment as usual (TAU). If a participant is allocated to the cognitive therapy plus TAU condition then the participant will meet with a therapist on initially a weekly basis and receive up to 8 sessions of CBT over a 2 month period. The participant will also have regular assessments conducted by a researcher who is independent to the treatment group. It is predicted that those people receiving CBT will improve on measures of symptoms, and particularly for measures of visual hallucinations.