Department of Psychology, Institute of Psychiatry, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
St Thomas' Hospital, London, UK
University of Manchester, Manchester, UK
University College London, UK
University of East Anglia, Norwich, UK
Institute of Psychiatry, London, UK
I am writing to reply to Turkington et al (2002: p. 525), who claim in their interesting and recently published paper on cognitivebehavioural therapy (CBT) for psychosis, that The NNT [numbers needed to treat] of 13 for improvement in overall symptoms was compatible with the results achieved when CBT was delivered by expert therapists (Kuipers et al, 1997). We do not think this claim is justified.
First, in our study 64% of the CBT group achieved clinical improvement compared with 47% of the controls (Kuipers et al, 1997). We did not present the NNT but they are 6 at the end of treatment and 3 at the end of follow-up (Kuipers et al, 1998).
Second, the two studies address different questions in different samples. Our study tested whether CBT for psychosis could improve outcome compared with treatment as usual, in a sample comprising subjects deliberately chosen to have at least one distressing, positive, medication-resistant symptom of psychosis (not from lists of patients with schizophrenia receiving treatment; Turkington et al, 2002: p. 523). We were aiming at a treatment-resistant group, a rather different sample from that recruited by Turkington and colleagues. Neither study compared 9 months of CBT with a briefer intervention. Nor did they test the efficacy of two different kinds of CBT.
We believe that it is misleading to claim comparability of trials between expert and non-expert therapists, and between results from 6 sessions and 20 sessions. Evidence for the efficacy of CBT for psychosis is at an early and promising stage; we think it is unhelpful to make unsubstantiated comparisons across trials, and hope that these comments provide some clarification.
REFERENCES
Kuipers, E., Garety, P., Fowler, D., et al (1997) LondonEast Anglia randomised controlled trial of cognitivebehavioural therapy for psychosis. I. Effects of the treatment phase. British Journal of Psychiatry, 171, 319-327.[Abstract]
Kuipers, E., Fowler, D., Garety, P., et al (1998) LondonEast Anglia randomised controlled trial of cognitivebehavioural therapy for psychosis. III. Follow-up and economic evaluation at 18 months. British Journal of Psychiatry, 173, 61-68.[Abstract]
Turkington, D., Kingdon, D., Turner, T., et al
(2002) Effectiveness of a brief cognitivebehavioural
therapy intervention in the treatment of schizophrenia. British
Journal of Psychiatry, 180,
523-527.
Department of Psychiatry, University of Newcastle upon Tyne, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne NEI 4LP, UK
Our study was designed specifically to answer the question raised by Jones et al (1999) of whether the benefits achieved by expert therapists in research settings could be replicated by non-expert therapists working in community mental health teams. An end-of-therapy comparison was therefore necessary with one of the methodologically robust studies quoted in the above review. Kuipers et al (1997) was chosen because a similar, good clinical outcome analysis on overall symptoms had been reported at end of therapy. The appropriate end-of-therapy comparison is 14/28 (50%) for cognitivebehavioural therapy (CBT) as measured at the level of 20% improvement in overall symptoms in the original Kuipers et al (1997) paper compared with 112/257 (44%) as measured at the level of a 25% improvement in our study. These results show a comparable effect size for CBT in the two studies, considering that our study had to satisfy a more stringent criterion for a good clinical outcome. The difference in the numbers needed to treat is solely due to an improved performance in our treatment as usual group compared with standard care.
It is certainly correct to state that the two study populations were different by definition. However, consideration of the demographics as reported in the two papers shows that there was little difference in those who actually ended up being enrolled in the two studies. The mean number of admissions in Kuipers et al (1997) was 5.2 for the CBT group and 4.3 for standard care and in our study 4.71 for CBT and 5.18 for treatment as usual. We ended up enrolling a more treatment-resistant group because of the fact that patients with schizophrenia whose symptoms were well controlled with medication often did not see the need to enter the study when it was offered to them.
It is certainly true that the CBT delivered by Kuipers and colleagues was of 20 sessions' duration with a more sophisticated treatment manual. This makes the result of our brief CBT intervention as delivered by psychiatric nurses all the more impressive. We await the analysis of our short-term follow-up results to see whether the impressive durability results reported above can be equalled. If CBT is to make a real impact in terms of the management of schizophrenia, it will need to be delivered by non-expert therapists in community mental health teams. The real issues for expert cognitive therapists are to organise training courses, provide supervision and to deliver more complex CBT for those patients with schizophrenia who are more psychologically difficult or who have comorbidity such as post-traumatic stress disorder, alcohol dependence and social phobia. There is therefore a potential role for both expert and non-expert therapists in the management of every patient with schizophrenia.
REFERENCES
Jones, C., Cormac, I., Mota, J., et al (1999) Cognitive behaviour therapy for schizophrenia. In Cochrane Library, issue 4. Oxford: Update Software.
Kuipers, E., Garety, P., Fowler, D., et al (1997) LondonEast Anglia randomised controlled trial of cognitivebehavioural therapy for psychosis. I. Effects of the treatment phase. British Journal of Psychiatry, 171, 319-327.[Abstract]
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