Schizophrenia Research 120 (2010) 217–224

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Schizophrenia Research

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Cognitive remediation therapy in schizophrenia: Cost-effectiveness analysis

Anita Patel a, Martin Knapp a,b, Renee Romeo a,⁎, Clare Reeder c,Pall Matthiasson d, Brian Everitt e, Til Wykes c

a Centre for the Economics of Mental Health, Health Service and Population Research Department, Box 24, Institute of Psychiatry,King's College London, De Crespigny Park, London SE5 8AF, United Kingdomb Personal Social Services Research Unit, London School of Economics and Political Science, Houghton Street, London WC2A 2AE, United Kingdomc Department of Psychology, Box 77, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, United Kingdomd Section of Neuroimaging, Box 67, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, United Kingdome Department of Biostatistics and Computing, Box 20, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, United Kingdom

a r t i c l e i n f o

⁎ Corresponding author. Tel.: +44 20 7848 0588; faE-mail addresses: anita.patel@iop.kcl.ac.uk (A. Pate

martin.knapp@iop.kcl.ac.uk (M. Knapp), renee.romeo@(R. Romeo), clare.reeder@iop.kcl.ac.uk (C. Reeder), til.(T. Wykes).

0920-9964/$ – see front matter © 2009 Elsevier B.V.doi:10.1016/j.schres.2009.12.003

a b s t r a c t

Article history:Received 4 June 2009Received in revised form 26 October 2009Accepted 3 December 2009Available online 6 January 2010

Purpose: There is a lack of evidence on the cost-effectiveness of cognitive remediation therapy(CRT).Methods: Randomised controlled trial comparing usual care plus CRT with usual care alone.Participants had a diagnosis of schizophrenia and cognitive and social functioning difficulties.Health/social care and societal costs were estimated at 14 weeks (time 2) and 40 weeks(time 3) after randomisation. The outcome, proportion of participants improving their workingmemory since baseline, was combined with costs to explore cost-effectiveness.Results: 85 participants were recruited. There were no differences in total health/social care orsocietal costs between the two groups at either time 2 or time 3. An additional 21% ofparticipants in the CRT group improved their working memory at both follow-ups. Whenplacing these cost and outcomes in hypothetical scenarios concerning how much policy-makers would pay for another 1% of participants improving their working memory, there wasmore than an 80% chance that CRT would be cost-effective compared to usual care; at time 3,the likelihood of cost-effectiveness peaked at 30% even for investments up to £5000.Conclusions: CRT can improve memory among people with schizophrenia and cognitive deficitsat no additional cost. Although cost-effective in the short term, CRT may have limited potentialto save costs in themedium term because it could increase take up of services. This could conferimportant longer termbenefits for the patient group examined here, in terms of improved socialfunctioning and less reliance on services. This can only be ascertained through longer follow-up.

© 2009 Elsevier B.V. All rights reserved.

Keywords:Cognitive remediationPsychological therapyCost-effectiveness

1. Introduction

Health and social care interventions for schizophrenia aimto improve symptoms, long-term health and quality of life. Awide range of services are involved in providing thistreatment and support, with inevitable differences in their

x: +44 20 7848 0458.l),iop.kcl.ac.uk

wykes@iop.kcl.ac.uk

All rights reserved.

clinical and economic consequences. Most economic evidencein this area focuses on the cost-effectiveness of medicationsand different ways of organising mental health care, andthere is still little economic evidence on psychologicaltreatments. Cognitive remediation therapy (CRT) is onesuch treatment, aimed at improving cognition levels inpeople with schizophrenia, which can subsequently improvefunctioning outcomes. A randomised controlled trial hasdemonstrated that CRT can provide durable improvements inmemory compared with usual care (Wykes et al., 2007). Thispaper examines whether CRT is also cost-effective. Given thebroad ranging impacts of schizophrenia, providing effective

218 A. Patel et al. / Schizophrenia Research 120 (2010) 217–224

treatments is relevant not just to the providers/funders ofsuch treatments but also to other stakeholders (Knapp et al.,2004). We therefore examine costs and cost-effectivenessfrom two points of view: that of health and social careproviders who need to optimise the value obtained from theirlimited budgets and that of wider society, incorporating thesehealth/social care costs plus the potential value of lostproduction to society due to illness-related time taken offwork by those in employment, the often more substantialgovernment expenditure on social security benefits resultingfrom people being unable to work and, finally, criminal justicesystem costs due to links between mental illness and crime(Knapp et al., 2004). A limitation of traditional approaches toexamining cost-effectiveness is that they do not address theimportant judgement that policy-makers need to make abouthow much they would be willing to pay for a health (orrelated) improvement. We therefore undertook neweranalytical approaches which incorporate such value judge-ments into the cost-effectiveness ‘answer’.

2. Methods

2.1. Trial design

Full details of the study design, recruitment process,participants, randomisation, intervention and outcome as-sessment are given by Wykes et al. (2007).

In brief, people with schizophrenia for whom there wasevidence of cognitive difficulties were recruited from localcommunity mental health teams in the South London andMaudsley National Health Service (NHS) Trust (London,England) between February 1999 and December 2002. In asingle-blind trial, they were randomised (after baselineassessments) to receive either cognitive remediation therapy(CRT) in addition to usual care or usual care alone.

After complete description of the study to the subjects,written informed consent was obtained. The trial was carriedout in accordance with the Code of Ethics of the WorldMedical Association (Declaration of Helsinki) and the studyprotocol was approved by the Institute of Psychiatry/SouthLondon and Maudsley NHS Trust Ethical Committee. The trialregistration number is ISRCTN44277627.

2.2. Intervention

CRT was a manual-based programme (Delahunty et al.,2002) and consisted of 40 face-to-face sessions per partici-pant, each involving a number of paper and pencil tasks thatprovide practice in a variety of cognitive skills set out in themanual. It consisted of three modules (cognitive flexibility,working memory and planning) (Delahunty et al., 2002;Reeder et al., 2004) and was based on the principles ofteaching new efficient information processing strategies,individualising therapy and aiding transfer of cognitivegains into the real world. Therapy was delivered to indivi-duals on at least three days per week until 40 sessions werecompleted. Therapists were graduate psychologists who hadfollowed a dedicated training programme involving theory,observation and supervised practice sessions. Therapistfidelity checks showed compliance with the manual.

2.3. Data collection

Information about study participants' use of services andother resources were collected retrospectively at threeassessment points: baseline (for the previous 6 month period;hereafter ‘time 1’), 14 weeks after randomisation (for theprevious 3 month period; ‘time 2’) and 40 weeks afterrandomisation (for the previous 6 month period; ‘time 3’).All such data were recorded for each participant individuallyon the Client Socio-Demographic and Service Receipt Inven-tory (CSSRI) (Chisholm et al., 2000); this covered questionsabout participants' current demographic profile, living situa-tion, employment status, income, lost days fromwork, receiptof social security benefits and use of health care, social care,voluntary care and criminal justice system services. Given thebroad range of economic impacts of interest, data werecollected through a combination of participant self-report(through face-to-face interviews carried out by graduateresearch psychologists), health care staff and trust records.

2.4. Costs

Quantities of services and other resources used byparticipants (as measured by the CSSRI) were multipliedwith the cost of one unit of each of those services/resources(often termed ‘unit costs’; for example, the unit cost ofhospital inpatient services was the cost of one inpatient day).These calculations were made for each study participant, foreach service/resource we measured, at each assessmentpoint. Unit cost estimates, their sources and any assumptionsmade for their estimation are described in Appendix A. Totalcosts (for each participant, at each assessment point) werethen computed from two points of view (or ‘perspectives’):

(i) the health and social care system (including voluntarysector services)

(ii) societal, which incorporates the aforementionedhealth and social care system perspective, plus thecosts of days off work, social security benefits andcriminal justice services.

Baseline (for the previous 6 month period; hereafter ‘time1’), 14 weeks after randomisation (for the previous 3 monthperiod; ‘time 2’) and 40 weeks after randomisation (for theprevious 6 month period; ‘time 3’).

In line with the CSSRI data, summary costs represent theprevious 6 months at baseline, the previous 3 months at time2 and the previous 6 months at time 3. All costs are reportedin pounds sterling (£) at 2000/2001 prices (the period inwhich most patient data were collected); multiplyingreported figures by 1.31 would give an approximate indica-tion of costs at 2007/08 prices (inflating using the Hospitaland Community Health Services Pay and Prices Index (Curtis,2008). A conversion rate of £1=$1.597, based on 2001purchasing power parities (OECD, 2001) which equalise thepurchasing power of the two currencies, can be used toconvert costs to United States dollars.

2.5. Cost of CRT

The unit cost for CRT was calculated as part of a relatedstudy (Wykes et al., 2003) and includes costs of: contact and

219A. Patel et al. / Schizophrenia Research 120 (2010) 217–224

non-contact time of the therapists (assistant psychologists);contact and non-contact time of clinical psychologists whotrained and supervised the therapists; and paper materialsused during the therapist training sessions and CRT sessions.It also includes appropriate overheads and other salary-related costs borne by employers (contributions to statenational insurance and occupational pension schemes). Theunit cost was estimated as a total cost per participant per 40-session course (£631.90) and divided by 40 to obtain anaverage cost per session (£15.85), which was applied toindividual-level data according to the number of sessionsattended by each person. Costs of missed sessions were notaccounted for.

2.6. Outcome measure

The trial's primary outcome was working memory, whichwas chosen as a primary outcome because it has beenrecognised as an important contributor to the variance infunctional outcomes. It was measured using the total rawscore from the well-known Digit Span: Wechsler AdultIntelligence Scale-III (WAIS-III) (Wechsler, 1981). To allowa cost-effectiveness analysis based on a clinically meaningfulinterpretation of this outcome measure, we examined thenumber of ‘improvers’ on this scale rather than mean totalscore. Improvers were defined as those gaining ≥2 pointssince baseline, an improvement level which has beensuggested in recent studies to contribute to functionalimprovements (Bryson and Bell, 2003).

2.7. Analyses

Data were double-entered and were analysed using SPSSfor Windows Release 12.0.1 (SPSS Inc., 1989–2001) andSTATA 8.2 for Windows (StataCorp LP, 1985–2004). Partici-pants were analysed in the group to which they wererandomised regardless of adherence to treatment.

Costs and outcomes were compared at both time 2 andtime 3. Costs are reported as mean values with standarddeviations. Memory improvement rates are reported as thenumber and percentage of improvers. Mean differences and95% confidence intervals (CIs) were obtained by non-parametric bootstrap regressions (1000 repetitions) (Briggset al., 1997). For cost comparisons at time 2 and time 3,regressions included covariates for baseline values of equiv-alent cost categories and baseline total score on the Positiveand Negative Syndrome Scale (PANSS) (Kay et al., 1987), ameasure of symptoms, because of their potential effect onfollow-up costs. Similarly, time 2 and time 3 comparisons ofmemory improvement rates included covariates for baselineWAIS-III digit span total raw score and baseline total PANSSscore.

Cost-effectiveness was assessed from both of the costperspectives described earlier (health/social care and socie-tal). We planned to calculate incremental cost-effectivenessratios where both costs and outcomes were higher for onegroup compared to the other. This would be calculated as thedifference in costs between the two groups divided by thedifference the percentage of people who improved on theWAIS-III score between baseline and follow-up; thus repre-senting the additional cost of any additional outcomes.

However, thismore traditional approach to assessing cost-effectiveness carries two limitations: it does not allow therepresentation of uncertainty in the estimates (becausecalculating confidence intervals for ratios is not straightfor-ward) and it does not take account of how much policy-makers would actually be willing to pay for an extra 1% ofimprovers in theWAIS-III. Such limitations are addressed by anewer analytical approach, cost-effectiveness acceptabilitycurves (CEACs; van Hout et al., 1994). In the absence of priorinformation about exactly howmuch policy-makers would bewilling to pay for the outcome of interest, CEACs allow theexploration of a range of hypothetical values among whichthe true ‘willingness to pay’ could fall. CEACs were con-structed based on the net benefit approach, a calculation thatincorporates the hypothetical willingness to pay level, usingthe following formula:

Net benefit = ðλ� EÞ−C

where E is effectiveness (whether the individual improved onthe WAIS-III digit span total raw score), C is cost, and λ is thewillingness to pay for one additional unit of outcome (i.e. anadditional 1% of improvers on the WAIS-III digit span totalraw score). A series of net benefits were calculated for eachindividual for an assumed range of λ values between £0 and£1950 (in £150 increments). After calculating net benefits foreach individual for each value of λ, coefficients of differencesin net benefits between groups were obtained through aseries of bootstrapped linear regressions (1000 repetitions) ofgroup upon net benefit. Similarly to all other comparativeanalyses, the regressions also included covariates for baselinevalues of the relevant cost category, WAIS-III digit span totalraw score and total PANSS score. The resulting coefficientswere examined to calculate the proportion of bootstrapsamples that showed the CRT group having a greater netbenefit than the usual care group for each value of λ. Finally,these proportions were plotted to generate CEACs from bothstudy perspectives at time 2 and time 3.

3. Results

Eighty-five participants were recruited; of these, 43 wererandomised to cognitive remediation therapy and 42 to usualcare. Participants' characteristics and clinical outcomes havebeen described elsewhere (Wykes et al., 2007). To summa-rise, 62 (73%) of the sample were male, mean age was36 years and 44 (52%) had been in contact with psychiatricservices for at least 10 years. While 40 (47%) were living inindependent accommodation or with their family, 34 (40%)had never lived independently.

3.1. Use of services/resources

Theuse of services/resourceswasnot compared statistically,firstly because the economic evaluation was focused on costsand cost-effectiveness and, secondly, to avoid problemsassociated with multiple testing. Therefore, patterns of ser-vice/resource use are describedwithout statistical comparisons.

Participants' use of services/resources at time 1 has beendescribed elsewhere (Patel et al., 2006) and was broadlybalanced between the groups. They made use of a wide range

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of accommodation, health and social care services, withspecialist accommodation and hospital inpatient servicesbeing themost commonly used services in both groups duringeach of the follow-up periods (Tables 1 and 2). The mostheavily used non-residential services were day care, commu-nitymental health centres and community psychiatric nurses.Contacts with the criminal justice systemwere minimal, withone participant in the usual care group having one criminalcourt appearance at time 2 and another participant in thesame group having one police contact at time 3.

There appeared to be some differences in patterns ofservice use between the groups. For example, at time 3, theCRT group had an average of 6 more psychiatric rehabilitationinpatient days, 7more day care attendances, 2 more sheltered

Table 1Use of services/resources at time 2 (previous 3 months).

CRT

Unit Valid n

CRT Sessions 43

Specialist accommodationStaffed full-time, part-time or unstaffed Days 41

Hospital inpatient servicesAcute Days 41Psychiatric rehabilitation Days 41Long-stay Days 41Emergency/crisis centre Days 41General medical Days 41Total Days 41

Hospital outpatient carePsychiatric Attendances 41Non-psychiatric Attendances 41Day hospital Attendances 41Other a Attendances 41

Community-based day servicesCommunity mental health centre Attendances 41Day care Attendances 41Group therapy Attendances 41Sheltered workshop Attendances 41Specialist education Attendances 41Other b Attendances 41

Community-based professionalsPsychiatrist Contacts 41Psychologist Contacts 41General practitioner Contacts 41District nurse Contacts 41Community psychiatric nurse Contacts 41Social worker Contacts 41Occupational therapist Contacts 41Home help/care worker Contacts 41First other professional c Contacts 41Second other professional d Contacts 41

Criminal justice system servicesPolice Contacts 41Stay in police/prison cell Nights 41Psychiatric assessment in custody Assessments 41Criminal court Appearances 41Civil court Appearances 41

a Clozapine clinic and movement disorder clinic.b Swimming, education centre and relaxation.c Assistant psychologist, music therapist, housing officer, nurse, doctor, psychiatrd Key worker and teacher.

workshop attendances and 5 more occupational therapistcontacts compared to the usual care group. The usual caregroup had 3 more community psychiatric nurse contacts attime 2 and 5 more such contacts at time 3.

In terms of take-up of CRT in the intervention group,participants attended an average of 37 sessions; 36 partici-pants attended all 40 sessions and, of the remainder, fourattended between 32 and 37 sessions, one attended foursessions and one attended none.

3.2. Costs

While the CRT group had numerically lower costs than theusual care (only) group from both cost perspectives at both

Usual care

Mean (SD) Valid n Mean (SD)

36.93 (10) 42 0 –

25.68 (41) 39 21.12 (38)

2.72 (13) 39 0.77 (5)16.74 (33) 39 20.36 (37)1.24 (8) 39 2.34 (15)0 – 39 0 –

0.07 (0.5) 39 0 –

20.78 (37) 39 23.47 (39)

0.41 (1) 39 0.59 (1)0.07 (0.3) 39 0.10 (1)0.39 (2) 39 0.31 (2)0.15 (1) 39 0.10 (1)

5.88 (15) 39 4.08 (9)9.93 (17) 39 9.28 (19)0.83 (4) 39 2.10 (7)2.59 (11) 39 0.03 (0.16)0.29 (2) 39 1.51 (6)0 – 39 1.28 (5)

1.90 (3) 39 2.58 (3)1.51 (6) 39 0.63 (2)0.68 (2) 39 0.36 (1)0.15 (1) 39 04.95 (7) 39 8.44 (15)0.54 (1) 39 1.76 (3)2.98 (6) 39 1.49 (7)0 39 0.31 (2)4.95 (13) 39 1.56 (4)0.59 (4) 39 0.26 (2)

0 – 38 0 –

0 – 38 0 –

0 – 38 0 –

0 – 38 0.03 (0.16)0 – 38 0 –

ic nurse, key worker, counsellor, osteopath and dentist.

Table 2Use of services/resources at time 3 (previous 6 months).

CRT Usual care

Unit Valid n Mean (SD) Valid n Mean (SD)

Specialist accommodationStaffed full-time, part-time or unstaffed Days 41 57.52 (85) 37 50.36 (81)

Hospital inpatient servicesAcute Days 41 0 – 37 7.00 (26)Psychiatric rehabilitation Days 41 33.76 (67) 37 27.62 (64)Long-stay Days 41 4.45 (29) 37 0 –

Emergency/crisis centre Days 41 0 – 37 0 –

General medical Days 41 0 – 37 0 –

Total Days 41 38.21 (71) 37 34.62 (69)

Hospital outpatient carePsychiatric Attendances 41 1.78 (5) 37 1.27 (3)Non-psychiatric Attendances 41 0.07 (0.26) 37 0.35 (2)Day hospital Attendances 41 1.20 (6) 37 0Other a Attendances 41 0.44 (2) 37 0

Community-based day servicesCommunity mental health centre Attendances 41 9.88 (27) 37 10.38 (23)Day care Attendances 41 18.37 (29) 37 11.19 (27)Group therapy Attendances 41 0.29 (2) 37 1.54 (6)Sheltered workshop Attendances 41 3.17 (20) 37 1.19 (6)Specialist education Attendances 41 0.68 (4) 37 0.65 (4)Other b Attendances 41 2.90 (9) 37 4.38 (17)

Community-based professionalsPsychiatrist Contacts 41 2.10 (3) 37 2.95 (4)Psychologist Contacts 41 0.59 (2) 37 0.41 (2)General practitioner Contacts 41 0.85 (4) 37 0.38 (1)District nurse Contacts 41 0 – 37 0 –

Community psychiatric nurse Contacts 41 8.98 (16) 37 13.54 (32)Social worker Contacts 41 0.49 (1) 37 1.57 (4)Occupational therapist Contacts 41 4.95 (13) 37 0.24 (1)Home help/care worker Contacts 41 7.24 (34) 37 7.30 (25)First other professional c Contacts 41 2.98 (15) 37 3.32 (15)Second other professional d Contacts 41 1.02 (6) 37 0.97 (6)

Criminal justice system servicesPolice Contacts 40 0 – 37 0.03 (0.16)Stay in police/prison cell Nights 40 0 – 37 0 –

Psychiatric assessment in custody Assessments 40 0 – 37 0 –

Criminal court Appearances 40 0 – 37 0 –

Civil court Appearances 40 0 – 37 0 –

a Clozaril blood test and weight clinic.b Anxiety management course, art therapy, church befriender, clozaril clinic, college, drop-in centre, gym, exercise class, rehabilitation centre, user group and

work placement.c Art therapist, community care officer, housing officer, key worker, befriender, reflexologist, senior house officer and staff nurse.d Clozapine nurse and drop-in centre.

221A. Patel et al. / Schizophrenia Research 120 (2010) 217–224

time 2 and time 3, 95% confidence intervals around the meandifferences indicate that these were not statistically signifi-cant (Table 3). Therefore, while it can be concluded that CRThad no impact on health and social care costs or societal costsoverall, there is a possibility that some of the additional costsof CRT were being offset elsewhere.

3.3. Outcomes

Compared to the usual care alone group, the CRT groupshowed advantages in working memory at both time 2 andtime 3. The estimated advantage to the CRT group was 1.33points (95% confidence interval: 0.43, 2.16) and the effect sizewas 0.34 (95% confidence interval: 0.1, 0.55) (Wykes et al.,2007). Working memory also improved by a clinically

significant level in a significantly greater proportion of theCRT group compared with the usual care group at bothfollow-up points (Table 4).

3.4. Cost-effectiveness

Given that the CRT group showed better outcomes at noadditional cost from either cost perspective and at both time 2and time 3, it was not necessary to calculate incremental cost-effectiveness ratios. However, it is appropriate to examinecost-effectiveness acceptability curves which represent howlikely it is that CRT is cost-effective compared to usual carealone within the context of how much policy-makers may bewilling to pay for 1% increases in the proportion of studyparticipants improving their working memory.

Table 3Mean costs and mean cost differences at times 1, 2 and 3.

Cost CRT Usual care Mean difference (CRT — Usual care) a 95% confidence interval

n Mean (SD) n Mean SD

CRT 43 585 (153) 42 0 – 586 538, 626

Time 1Health and social care, excluding CRT 40 13 448 (11 508) 39 12 101 (11 007) 1348 −4113, 5866Other 41 2290 (1268) 42 2293 (1330) −3 −526, 591Societal, excluding CRT 40 15 769 (11 164) 39 14 442 (10 787) 1326 −3924, 5675

Time 2Health and social care, excluding CRT 41 7267 (6184) 39 8016 (7504) −1522 −3641, 951Health and social care, including CRT 41 7866 (6163) 39 8016 (7504) −917 −3044, 1554Other 41 1112 (618) 39 1226 (524) −143 −364, 83Societal, excluding CRT 41 8379 (6067) 39 9242 (7429) −1688 −3803, 723Societal, including CRT 41 8978 (6045) 39 9242 (7429) −1083 −3202, 1349

Time 3Health and social care, excluding CRT 41 13 792 (11 626) 37 13 029 (12 213) −726 −4540, 3287Health and social care, including CRT 41 14 391 (11 608) 37 13 029 (12 213) −121 −3926, 3876Other 41 1947 (1139) 37 2309 (1025) −358 −809, 119Societal, excluding CRT 41 15 740 (11 382) 37 15 338 (12 001) −1136 −5041, 2749Societal, including CRT 41 16 338 (11 362) 37 15 338 (12 001) −531 −4441, 3345

a Time 2 and time 3 cost differences are adjusted for the baseline value of each cost category and baseline total PANSS score.

Table 4Number (%) of participants gaining ≥2 points on WAIS-III digit span total raw score since baseline.

CRT Usual care Mean difference (CRT — Usual care) a 95% confidence interval

n n gaining ≥2 points % n n gaining≥2 points %

Time 2 39 18 46 38 7 18 21% 0, 41Time 3 36 14 39 34 5 15 21% 2, 41

a Adjusted for baseline WAIS-III digit span total raw score and total PANSS score.

222 A. Patel et al. / Schizophrenia Research 120 (2010) 217–224

The sample sizes available for the CEAC analyses were 36and 34 for time 2 and time 3 respectively in the CRT group, and36 and 33 respectively in the usual care alone group. Weexamined whether there were differences between the fullrandomised sample and those included in the cost-effectivenessanalysis; there were no differences at baseline, time 2 or time 3with respect to age, chronicity of schizophrenia (contact andfirst admission), total symptom score or social functioning. Pre-morbid IQ was not statistically significant between thoseincluded and those who dropped out, but there was a tendency(p=0.06) for those who dropped out to have higher IQ.

Fig. 1. Probability that CRT is cost-effective at time 2.

Cost-effectiveness acceptability curves for time 2 suggestthat the likelihood of CRT being cost-effective compared tousual care is high: in 80% of the bootstrap samples, the CRTgroup had a greater net benefit than the usual care groupeven when it was assumed that policy-makers would paynothing (i.e. if λ=zero) for an additional 1% of improvers onthe WAIS-III (Fig. 1). This conclusion held from both costperspectives. At time 3, however, probabilities of cost-effectiveness are greatly reduced, not exceeding 20% evenwhen the outcome is valued at £1950 (Fig. 2). Furtheranalyses for time 3 (not illustrated here) suggested that even

Fig. 2. Probability that CRT is cost-effective at time 3.

223A. Patel et al. / Schizophrenia Research 120 (2010) 217–224

if policy-makers valued memory improvements as high as£5000 per an additional 1% of improvers, the likelihood ofcost-effectiveness would only reach 23% from a health andsocial care perspective and 30% from a societal perspective.The reduced probability of cost-effectiveness at time 3may bea consequence of the smaller cost advantage at time 3, assuggested by the confidence intervals being balanced aroundzero (compared with a greater balance towards cost savingsat time 2) (Table 3).

4. Discussion

This is the first economic evaluation of cognitive remedi-ation therapy. It measured costs comprehensively to includenot only health/social care costs, but also other costs falling tobroader society. Combining costs with a widely used measureof working memory within a randomised controlled trialdemonstrated that CRT can bring about significant improve-ments in memory among people with schizophrenia andcognitive deficits, and that these improvements are achievedat no additional cost compared to usual care alone.

This study joins a very small group of previous economicevaluations of psychological therapies for treating peoplewith schizophrenia. Although there is now a burgeoningliterature on the effectiveness of psycho-social treatment (e.g.Penn et al., 2005), it is very rare for there to be a cost-effectiveness component. One exception is the evaluation ofadherence therapy, an intervention that was found to bemore cost-effective than usual care in the first trial in SouthLondon (Healey et al., 1998), but which was not effectivewhen evaluated more recently in a four-site European trial(Gray et al., 2006). A cost and outcomes evaluation (whichdid not formally link these together in the form of a cost-effectiveness analysis) of cognitive behaviour therapy fortreating people with treatment-resistant psychosis foundimprovements in symptoms and that the additional costs ofthe therapy were offset by subsequent reductions in serviceutilisation (Kuipers et al., 1998). There have also beenimputations of cost-effectiveness, such as in the Australia-wide examination of current compared to guideline-driventreatment for schizophrenia by Andrews et al. (2003).

Our study had some limitations. Firstly, it was conductedin South London and service use patterns and costs may notgeneralise to other locations or care settings. Secondly, thecost-effectiveness analyses were based on only one elementof cognition, working memory. Post-hoc analyses based onother cognitive outcomes or a composite cognition score mayoffer alternative cost-effectiveness conclusions. Finally, it wasbased on a relatively small sample compared to sample sizesused in, for example, pharmacological trials. The study waspowered on the primary outcomemeasure but not on the costor cost-effectiveness measures, which remains a commonlimitation of economic evaluations for both mental andphysical health interventions. The generally highly skeweddistribution of costs (because of a high number of people withvery low costs, and a few with very high costs) tends tonecessitate a much larger sample to power the test of theeconomic hypothesis compared to the sample size needed fortesting the core clinical hypothesis (Sturm et al., 1999). This isone reason why plotting the cost-effectiveness acceptabilitycurve, located within a ‘policy-making’ approach to evalua-

tion, has merit. Our results show that while the traditional‘incremental cost-effectiveness ratio’ approach to assessingcost-effectiveness suggests a straightforward interpretationof the results in favour of CRT, the CEAC approach suggestsuncertainty around this conclusion at time 3.

While cost differences over time were not tested statis-tically, it is interesting to note that the size of the mean costdifference is numerically lower at time 3 than at time 2,despite time 3 costs representing a longer assessment period(six months rather than three). This could suggest that anypotential cost savings are more likely to occur in the short-term, while participants are receiving CRT, but that they arenot sustained in the longer term.

The RCT only provided CRT for a short period in addition tousual services and after that initial treatment periodparticipants returned to the usual care services which wereprovided based on the clinical decisions of their primarymental health care team. If the absence of a cost differencerepresents little difference in the take-up of services (or evenan increase, as could be inferred from the increased use ofpsychiatric rehabilitation inpatient care, day care and shel-tered work by the CRT group in this study), this can beinterpreted as a positive outcome given that care is intendedto confer benefits for the patient group examined here.Indeed, over a longer period than was studied here, it mightbe hypothesised that the greater use of rehabilitation servicesby patients receiving CRT would lead to later cost-offsets.This, however, can only be conjecture in the absence of long-term evidence.

These results fit with the meta-analysis carried out byMcGurk and colleagues (2007). Their analysis shows that CRTeffects on distal outcomes, such as social functioning andemployment, are only clinically significant when CRT isprovided in the context of other active rehabilitationprogrammes aimed at these outcomes. Improved socialfunctioning and employment are likely to reduce costs asthey help people to be less dependent on psychiatric andother services. The conclusion from this meta-analysis,together with the cost-effectiveness results presented here,suggest that there would be an advantage in providing CRT inthe context of a comprehensive rehabilitation programme.

Role of funding sourceThis work was supported by a grant from the Department of Health

(grant number RFG 757) who had no role in study design, data analysis orinterpretation, writing the report or decision to submit the paper forpublication. The views expressed in this paper are those of the authors andnot necessarily those of the funder.

ContributorsTW, MK and BE designed the study, wrote the protocol and obtained

funding. TW and CR supervised participant recruitment and oversaw datacollection. AP, RR and MK were responsible for the economic analyses. PMassessed patients' psychiatric symptoms. All authors contributed to writingthe paper and had full access to all study.

Conflict of interestNone of the authors have any conflict of interest to declare.

AcknowledgementsNone.

224 A. Patel et al. / Schizophrenia Research 120 (2010) 217–224

Appendix A. Supplementary data

Supplementarydata associatedwith this article canbe found,in the online version, at doi:10.1016/j.schres.2009.12.003.

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