There are methodological issues with the research on the effectiveness of CBT for schixophrenia. In most reserach patients are also taking AP medication so it is hard to assess the effectiveness of the therapy (CBT) alone. Furthermore there are problems with meta-analysis studies as there is varied study quality as some studies may use different sample sizes, different lengths of therapy and experience of therapist. Some studies fail to randomly allocate participants which may translate into biased findings about the effectiveness of of cbt. Morevover a recent meta-analysis found using cbt as sole treatement had a 'small' therapuetic effect on key symptoms (assessed blind) which suggests cbt alone is not an effective therapy for schixophrenia
