Clinical Psychology and Psychotherapy Clin. Psychol. Psychother. 10, 302–315 (2003) Copyright © 2003 John Wiley & Sons, Ltd. Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/cpp.373 INTRODUCTION Cognitive Behavioural Therapy for People with Psychosis There is now good evidence that Cognitive Behav- ioural Therapy (CBT) can help psychotic clients Birchwood, Cochrane, & Macmillan (Drury, et al., 1996a, 1996b; Garety et al., 1997; Sensky et al., 2000; Tarrier et al., 1999). Which ingredient of the therapy leads to these improvements is, however, less clear. Garety et al. (1997) found that clients treated with CBT did better than clients given treat- ment as usual on a number of measures. However, Sensky et al. (2000) found that a befriending control group did as well as the CBT group at the end of treatment (although differences emerged at follow-up). Drury et al. (1996a, 1996b) report the use of CBT in acute psychosis. They found it su- perior to an activity control in reducing symptoms and distress and in shortening length of hospital stay. However, Haddock et al. (1999) found CBT and supportive counselling/psychotherapy to be equal in their effects on BPRS ratings in acute schizophrenic patients. This latter group con- ducted a larger study (Lewis et al., 2002) and found The Effect of Different Components of Psychological Therapy on People with Delusions: Five Experimental Single Cases Simon C. Jakes 1 * and John E. Rhodes 2 1 Macarthur Mental Health Service, Campbelltown NSW Australia 2 Department of Clinical Psychology, St. Anne’s Hospital, Haringey London, UK This study is a contribution to the investigation of the active ingredi- ent in psychological therapy for psychosis. Five people with chronic delusions were treated using a single-case experiment design. The treatment was broken down into components that were administered sequentially. A baseline phase was followed by three different treatment conditions (An A–B–C–D design). The treatments were (1) Solution-focused Therapy (2) Schema-focused cognitive therapy (3) Cognitive therapy focused on modification of the delusion. Three of the five clients responded to treatment with a large change in degree of belief in their delusion. Two clients improved during solution- focused therapy, one client improved during cognitive challenging of the delusion and one client changed during baseline. The implications of this study are discussed. Copyright © 2003 John Wiley & Sons, Ltd. * Correspondence to: S. Jakes, Macarthur Mental Health Service, Campbelltown, NSW 2560, Australia. Tel: 624 629 5400, Fax: 624 628 6101. E-mail: simon.jakes@swsahs.nsw.gov.au Practitioner Report