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John Geddes a Department of Psychiatry University of Oxford,
Warneford Hospital, Oxford OX3 7JX, b Medicines Evaluation Group, Centre for Health Economics,
University of York YO10 5DD, c Department of Psychiatry and
Behavioural Sciences, Royal Free and University College Medical School,
London W1N 8AA
Correspondence to: J Geddes
john.geddes{at}psych.ox.ac.uk
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Abstract |
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Objective:
To develop an evidence base for
recommendations on the use of atypical antipsychotics for patients with schizophrenia.
The most pressing clinical uncertainty arising from recent
advances in the management of schizophrenia1 is the role
of atypical antipsychotics. The term "atypical" was originally used to describe drugs that in animal models predict antipsychotic effects
but do not produce catalepsy We conducted a systematic review of the effectiveness and
tolerability of atypical versus conventional antipsychotics in the treatment of schizophrenia to inform the development of a clinical practice guideline. The primary outcomes we investigated were control
of psychotic symptoms and overall acceptability, although we also
looked at the possibility of studying outcomes such as quality of life
and rates of specific adverse effects. We decided beforehand to
examine the influence of the dose of the conventional drug, because
common side effects (such as extrapyramidal side effects and sedation)
are dose related, whereas efficacy reaches a plateau.2 The
recommended optimal dose is 6-12 mg/day haloperidol or its
equivalent,3 although higher doses are still commonly used.4 Evaluation of the relative efficacy and
tolerability of conventional and atypical antipsychotics must,
therefore, take into account the comparator dose.
Systematic reviews of individual atypical antipsychotic drugs
(clozapine,5 olanzapine,
6 7
quetiapine,
7 8
risperidone,
7 9 10
and
sertindole7) exist but were either unavailable or out of date at the time we were developing the guideline. Furthermore, they do
not formally assess the effect of dose or allow evaluation of atypical
antipsychotics as a group.
Inclusion criteria
Search strategy
Brief psychiatric rating scale13 16 item, 7 point severity scale; 5 positive, 2 negative, and 9 general symptom items Completed by clinician Range of possible scores 16-112 Patients with schizophrenia typically score about 33 at entry
to trialw30 Positive and negative syndrome
scale14 (derived from brief psychiatric rating scale) 30 item, 7 point severity scale; 7 positive, 7 negative, and 16 general psychopathology symptom items Completed by clinician Range of possible scores 30-210 (positive and negative symptom
groups are often reported separately; both score 7-49) Patients with schizophrenia typically score about 91 at entry
to trialw6 w31
Design:
Systematic overview and meta-regression
analyses of randomised controlled trials, as a basis for formal
development of guidelines.
Subjects:
12 649 patients in 52 randomised trials
comparing atypical antipsychotics (amisulpride, clozapine, olanzapine,
quetiapine, risperidone, and sertindole) with conventional
antipsychotics (usually haloperidol or chlorpromazine) or alternative
atypical antipsychotics.
Main outcome measures:
Overall symptom scores. Rate of
drop out (as a proxy for tolerability) and of side effects, notably
extrapyramidal side effects.
Results:
For both symptom reduction and drop out,
there was substantial heterogeneity between the results of trials,
including those evaluating the same atypical antipsychotic and
comparator drugs. Meta-regression suggested that dose of conventional
antipsychotic explained the heterogeneity. When the dose was
12
mg/day of haloperidol (or equivalent), atypical antipsychotics had no
benefits in terms of efficacy or overall tolerability, but they still
caused fewer extrapyramidal side effects.
Conclusions:
There is no clear evidence that
atypical antipsychotics are more effective or are better tolerated than
conventional antipsychotics. Conventional antipsychotics should usually
be used in the initial treatment of an episode of schizophrenia unless
the patient has previously not responded to these drugs or has
unacceptable extrapyramidal side effects.
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Introduction
Top
Abstract
Introduction
Methods
Results
Discussion
References
most notably clozapine. It is
also applied to drugs that are potentially more effective (particularly
against depressive, negative, or cognitive symptoms) or better
tolerated (especially causing fewer extrapyramidal side effects) than
conventional antipsychotics or have a different pharmacological
profile (such as blockade of serotonin 5-HT2
receptors). No definition is wholly satisfactory, partly because the
term atypical is relative rather than absolute. We use the term simply to refer to clozapine and all the novel antipsychotics introduced in
the past decade.
![]()
Methods
Top
Abstract
Introduction
Methods
Results
Discussion
References
We included randomised trials of atypical antipsychotics
(amisulpride, clozapine, olanzapine, quetiapine, risperidone, and
sertindole) against conventional antipsychotics or alternative atypical
antipsychotics in patients with schizophrenia or related disorders for
which data on efficacy or drop out were available.
We used optimally sensitive search strategies, based on a
combination of text and index terms of Medline, Embase, PsychLIT, and
the Cochrane Controlled Trial Register to locate randomised trials
comparing the effectiveness of atypical and conventional antipsychotic
drugs in the treatment of schizophrenia and related disorders (further
details of the search strategies and the trials included are available
on the BMJ 's website). Searches were limited to
compounds licensed in the United Kingdom. The expert knowledge and
experience of group members was used to augment the findings of the
search strategies, and we requested information on all comparative
trials of the atypical drugs from the relevant pharmaceutical
companies. We included identified trials up to a cut off date of 1 December 1998.
Scales of symptom reduction commonly used in randomised
trials
Statistical analyses
For the primary analyses of continuous outcome measures, we
calculated standardised effect sizes.15 The effect size is
a measure of the overlap in the distributions of scores on the outcome
between the two treatment groups; we represent this in the results as
the percentage of patients treated with comparator drug who did less
well than the average of the group given an atypical antipsychotic.
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Results |
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We identified 52 trials, including 12 649 patients, meeting the inclusion criteria. Most were short term (median follow up 6.5 weeks), although five trials provided follow up data for one year or more (see tables 1-21 on BMJ 's website).w1-w6 Most trials compared the effectiveness of atypical antipsychotics with haloperidol. Occasionally, chlorpromazine was also used, and flupenthixol, perphenazine, and zuclopenthixol were the comparators in one trial each. There was substantial drop out in most trials from each group. This made interpretation of the commonly used "last observation carried forward" analyses problematic as it introduced uncertainty about the actual clinical state of the patients after they left the study.
The results presented for individual drugs depend on the data available from the trials and mainly concern reduction in symptom score and drop out (see table 22 on BMJ 's website). For trials that detected a significant effect we also give an estimate of the magnitude of the effect in terms of points on the brief psychiatric rating scale. Measurement of secondary outcomes (such as extrapyramidal side effects) was not standardised between studies and so they are reported separately in the text. There were few data on quality of life, specific side effects, or cost effectiveness, and we have therefore not included these outcomes in this report.
Amisulpride
We identified four short term trials examining the
effectiveness of amisulpride compared with
haloperidolw7-w9 and flupenthixol.w10 The
standardised weighted mean difference was
0.35 (95% confidence interval
0.52 to
0.18) in favour of amisulpride, indicating that
about 64% of patients given a conventional antipsychotic had higher
(worse) symptom scores after treatment than the average patient treated
with amisulpride. The fixed pooled odds ratio for drop out was 0.55 (0.38 to 0.79) and the random effects pooled odds ratio was 0.54 (0.33 to 0.85). The standardised weighted mean difference estimate of the
effect on the Simpson Angus scale (a scale measuring extrapyramidal
side effects (range 0-4) was
0.44 (
0.26 to
0.61).
Clozapine
We identified 12 trials providing data on efficacyw4-w6 w11-w18 and 20 trials providing data on
tolerability.w4 w11-w27 Two long term trials were
identified.w4-w6 Ten trials compared clozapine with
haloperidolw6 w11 w13 w14 w17 w18 w20-w24 and
10 with chlorpromazine.w12 w13 w15 w16
w19 w22 w25-w27 One trial compared clozapine with an
individually based choice of conventional
antipsychotic.w4 w5 Several trials focused on treatment
resistant schizophrenia,w4-w6 w12 w13 w15-w17 one of
which included children and adolescents.w17 The
standardised weighted mean difference for the overall symptom score in
short term trials was
0.68 (
0.82 to
0.55) in favour of
clozapine, signifying that about 75% of patients given a conventional antipsychotic had higher symptom scores after treatment than the average patient treated with clozapine. Patients allocated to clozapine
were less likely to drop out (odds ratio 0.52 (0.40 to 0.67) with fixed
effects model), although the odds ratio became non-significant with the
random effects model (0.69 (0.45 to 1.19)).
Olanzapine
We identified four short term trials comparing olanzapine
with haloperidolw28-w30 or chlorpromazine.w31
The standardised weighted mean difference was
0.22 (
0.30 to
0.14) in favour of olanzapine, indicating that about 59% of
patients taking a conventional antipsychotic had higher symptom
scores after treatment than the average patient taking olanzapine. The pooled odds ratio for drop out was 0.52 (0.44 to 0.61) with the fixed
effects model and 0.63 (0.40 to 1.17) with the random effect model.
Quetiapine
Two short term trials compared quetiapine with
chlorpromazinew32 or haloperidol.w33 There
was no difference in the overall symptom score between quetiapine
and the conventional antipsychotic (standardised weighted mean
difference
0.03 (
0.23 to 0.18)), nor was there any reliable evidence of a reduced rate of drop out with quetiapine (odds ratio 0.70 (0.46 to 1.06)).
Risperidone
Six short termw34-w39 and two long term
trialsw1 w2 comparing therapeutic doses of risperidone
with a conventional antipsychotic provided data on overall symptom
score. The short term trials all compared risperidone with various
regimens of haloperidol. The two long term trials were naturalistic in
design, comparing the decision to use risperidone with the decision to use a conventional antipsychotic chosen at the discretion of the psychiatrist.
0.15 (
0.27 to
0.04) in favour of risperidone and the random effects standardised weighted mean difference was
0.16 (
0.47 to 0.16). We observed substantial heterogeneity between trials, reflected in the random effects estimate
and its wide confidence intervals (which include the point of no
difference between the treatments). Potential explanations for this
heterogeneity include interactions between the use of risperidone and
specific patient groups and variability in the comparators.
Data on dropout rates were provided by ten short term
trials.w34-w43 The comparator antipsychotics were
haloperidol,w34-w39 w42 w43
perphenazine,w40 and zuclopenthixol.w41 The
fixed effects pooled odds ratio for drop out from risperidone was 0.59 (0.46 to 0.74), and the random effects odds ratio was 0.62 (0.31 to
1.34).
Benefits from risperidone were observed on the Parkinson,
dyskinesia, and dystonia symptom scales. The standardised weighted mean
difference was
0.39 (
0.51 to
0.27) for the Parkinson scale,
0.26 (
0.39 to
0.12) for the dystonia scale, and
0.16
(
0.28 to
0.04) for the dyskinesia scale.
In two long term, naturalistic, intention to treat trials, 840 patients were randomised to risperidone or conventional
antipsychotics.w1 w2 Patients could switch between groups
and between conventional antipsychotics at the discretion of the
psychiatrist. In the study of Bouchard et al the mean daily comparator
dose of conventional antipsychotics was a chlorpromazine equivalent of
1006 (SD 1348) mg daily, median 551 mg daily.w2 The mean
dose of haloperidol used in the risperidone outcome of effectiveness
(ROSE) trial was 16.1 (13.3) mg daily.w1 At 12 months, the
pooled standardised weighted mean difference for the overall positive
and negative syndrome scale score was
0.40 (
0.27 to
0.54),
indicating that about 66% of patients treated with conventional
antipsychotics had higher symptom scores after treatment than the
average patient treated with risperidone.
Sertindole
Lundbeck voluntarily suspended marketing for sertindole in
the United Kingdom on 2 December 1998 because of reports of cardiac
arrhythmias and sudden death. This occurred during the late stages of
the development of this clinical practice guideline. We identified four
trials including 1549 patients comparing sertindole with
haloperidol.w3 w44-w46 One trial had one year of
randomised follow up.w3 The other trials lasted eight
weeks. Doses of haloperidol ranged from 4 mg to 16 mg daily. The trial
results were included in the meta-regression but are not given here
because the drug is not currently available.
Effect on positive and negative symptoms
Overall, no evidence was identified to suggest that any
individual atypical antipsychotic had a specific effect on either
positive or negative symptoms. Instead, benefits seemed evenly spread
between them (tables 1-21 on BMJ 's website).
Effect of dose of comparator antipsychotic (haloperidol or
chlorpromazine) on outcome
The dose of haloperidol significantly affected outcome in the
23 trials in which it was used. Within the range of mean doses of
haloperidol reported (about 6-22.5 mg daily), meta-regression
identified a significant advantage for atypical antipsychotics as the
dose of haloperidol increased; the coefficient describing the effect of
dose was
0.021 (
0.003 to
0.038). The observed advantage in
favour of the atypical drug disappeared as the dose of haloperidol
decreased. A similar effect was seen for chlorpromazine, which was used
in seven trials. Within the range of mean doses of chlorpromazine
(about 375-1000 mg daily), meta-regression identified a significant
advantage for atypical antipsychotics as the dose of chlorpromazine
increased (
1.14 (
1.68 to
0.58)).
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12mg/day, the random effects standardised weighted mean difference
was
0.09 (
0.07 to
0.26), whereas in those with a mean
haloperidol dose of >12 mg/day it was
0.28 (
0.13 to
0.44) (fig 1). There was no difference in dropout rates between atypical antipsychotics and haloperidol in the trials that used
12 mg/day haloperidol (pooled risk difference was
0.1% (
4.6% to 4.4%) with the random effects model, but the pooled drop out in trials using
>12 mg/day haloperidol was
8.3% (
1.3% to 15.2%) (fig 2). In
other words, the advantages of atypical antipsychotics in terms of
efficacy and dropout rates are not seen if haloperidol is used at doses
of 12mg/day or less. These results from the meta-regression analysis
were unaffected by the removal of trials including treatment resistant
patients, those taking sertindole, or long term trials (data not shown).
We examined whether the lower incidence of extrapyramidal
side effects with atypical antipsychotics was dose related. The trials
used a range of measures to describe side effects, making meta-analysis
and meta-regression problematic. Two large trials describe the side
effects experienced by patients receiving risperidonew39
or sertindolew46 compared with haloperidol at a fixed dose
of 10mg daily. Peushens et al used a questionnaire based assessment
tool to assess extrapyramidal side effects and reported a significant
benefit for risperidone (4-16 mg) over haloperidol for dystonia
(P=0.0004) and dyskinesia (P=0.0499).w39 In the trials of
sertindole versus 10 mg haloperidol we noted a 16% (10% to 22%)
reduction in the incidence of akathisia attributable to
sertindole.w46 Thus, reduced extrapyramidal side effects
remain apparent at lower doses of comparator drugs examined in the
available trials.
Comparison between atypical antipsychotics
We found no difference in pooled efficacy in two trials
comparing olanzapine and risperidone.w47 w48 Both trials
showed olanzapine was better tolerated, equivalent to about a 7%
(0.4% to 13.6%) difference in drop out. The two trials comparing
risperidone and clozapine randomised a total of only 146 patients and
had insufficient power to provide useful data.w49 w50
Indirect comparison in meta-regression models did not identify any
individual atypical antipsychotic as more or less effective when dose
of comparator drug was taken into account.
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Discussion |
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Two main conclusions can be drawn from this review. Firstly, taking the trial results at face value, atypical antipsychotics are slightly more effective and better tolerated in patients with schizophrenia. Atypical antipsychotics also have a significantly lower risk of causing extrapyramidal side effects. We found no reliable evidence of differential effects between atypical antipsychotics and we have therefore grouped them together in this discussion. Secondly, when we controlled for the higher than recommended dose of conventional antipsychotics used in some trials, a modest advantage in favour of atypical antipsychotics in terms of extrapyramidal side effects remains, but the differences in efficacy and overall tolerability disappear, suggesting that many of the perceived benefits of atypical antipsychotics are really due to excessive doses of the comparator drug used in the trials. Taking these points into account, we think it inappropriate to advocate the first line use of a new drug without clear evidence of overall superior efficacy or tolerability.
However, for patients who do not response adequately to a standard dose of a conventional antipsychotic or experience severe extrapyramidal side effects it is appropriate to use atypical antipsychotics. Because conventional antipsychotics have limited effectiveness and tolerability, a large proportion of patients will, by this criterion, be prescribed atypical antipsychotics, often relatively early on in treatment. One of the most important results of our meta-regression is the confirmation that using conventional drugs at excessive doses reduces efficacy and increases adverse effects.2 Pharmacokinetic variability means that the optimal dose for individual patients will vary, but doses above 12 mg haloperidol a day (or equivalent) do not normally seem appropriate. This point may prove as important to the overall care of patients with schizophrenia as the intrinsic benefits of atypical antipsychotics.
Debate around our conclusion that a conventional antipsychotic should normally be prescribed first is likely to centre on two factors. The first is the negative consequences on patient compliance as a result of extrapyramidal side effects. In other words, if initial treatment produces worse side effects, then the patient may be unwilling to try a second drug. However, our analysis shows that patients taking atypical antipsychotics have no lower dropout rates and no better response than patients taking the optimal dose of conventional antipsychotics. This suggests that the lower risk of extrapyramidal side effects seen with the atypical antipsychotics may be counterbalanced by their greater propensity to cause other side effects and highlights the importance of early detection and treatment of adverse effects. A common side effect of atypical antipsychotic drugs is appreciable weight gain,19 and there are also rarer but serious side effects such as agranulocytosis with clozapine. In addition, concordance with treatment is probably not determined solely, or even primarily, by specific drug side effects, but by many factors, including those related to the disorder and the therapeutic relationship. Secondly, it may be that the lower incidence of extrapyramidal side effects translates into a lower long term risk of tardive dyskinesia.20 However, to date, the evidence on this issue is preliminary and inconclusive.21
Cost issues
Atypical antipsychotics are more expensive than the
conventional drugs. Inevitably, therefore, cost has become part of the
controversy concerning their prescribing. We believe that cost is not a
crucial issue at present because the evidence and analyses described
above indicate that the new drugs have no unequivocal advantages for
first line use that would need to be set against their greater
acquisition costs.
Potential publication bias
As in all systematic overviews, the results are only as good
as the studies that contributed to the analyses. Publication is a major
source of systematic bias in overviews, where trials with positive
results are more likely to be published than those with neutral or
negative results, especially if the trials are small. We went to
considerable lengths to obtain data on trials that had not been
published and trials that were incompletely reported. There is no way
of estimating the magnitude of or potential for publication bias,
although since the direction of such a bias would normally be in favour
of the newer drugs, its existence would not undermine the results
presented here.
Beyond the randomised evidence
This review shows that in several key areas, evidence is
insufficient or absent. The trials have a median length of six weeks,
yet antipsychotic drugs are often used for many years
and
the conventional drugs are often used in depot form. The trials exclude
a large proportion of patients who are treated with these drugs
(including those with comorbid disorders). With the exception of
extrapyramidal side effects, there is little consistent reporting
of adverse events. There are few data on quality of life or clinically
relevant functional outcomes and few reliable data on the cost
effectiveness of atypical antipsychotics
none in the
United Kingdom.
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What is already known on this topic
Antipsychotic drugs have a central role in the treatment of schizophrenia Newer, atypical antipsychotics are increasingly considered superior to conventional drugs What this study addsAtypical antipsychotics have a similar effect on symptoms to
conventional antipsychotics at an average dose of Atypical antipsychotics cause fewer extrapyramidal side effects, but overall tolerability is similar to conventional drugs Conventional drugs should remain the first treatment, although atypical antipsychotic drugs are a valuable addition to treatment options, especially when extrapyramidal side effects are a problem |
Evidence and concordance
Implicit in the above considerations, as with all evidence
based recommendations, is the importance of an informed relationship
between doctor and patient in which treatment decisions can be based on
the likely beneficial and adverse effects of atypical and conventional
antipsychotics, patient preference, and clinical judgment. Given the
equivocal nature of the evidence, deviations from these recommendations
may, and should, occur. For example, antipsychotic drugs clearly have
different side effect profiles. The broader choice of drugs now
available increases the chance of finding a drug for an individual
patient that is tolerated as well as effective and thus makes adherence
more likely. In the near future it may also be possible to take
predictors of treatment response, such as pharmacogenomic
considerations, into account when deciding which antipsychotic to prescribe.
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Acknowledgments |
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We thank the investigators and sponsors who provided unpublished information to aid our work. The work described in this paper was done as part of a programme of guideline development undertaken by the Royal College of Psychiatrists Research Unit and the Centre for Outcomes Research and Effectiveness of the British Psychological Society. The recommendations presented in this article are the views of the technical development group and should not be considered to represent the views of the Royal College of Psychiatrists, the British Psychological Society, or the National Institute of Clinical Excellence.
Contributors: This paper was prepared by JG, NF, PH, and PB. JG chaired the guidelines development group for which this work was conducted, assisted with the meta-analyses, and drafted the paper. NF performed the meta-analyses and drafted the paper, PH and PB contributed to the planning and interpretation of the analyses and drafted the paper. Anne Burton, Jo Hobbins, and Gilli Orbach provided administrative support, Martin Eccles gave methodological advice and supervision, and Julie Glanville helped with the design and implementation of search strategies. JG acts as guarantor for the paper.
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Footnotes |
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Funding: English Department of Health as part of a larger programme of schizophrenia management guidelines to be undertaken by the National Institute of Clinical Excellence.
Competing interests: JG, as director of the Centre for Evidence Based Mental Health, has run workshops around the United Kingdom, organised independently, but often sponsored by pharmaceutical companies. The centre has therefore indirectly received fees and expenses from several of the companies who manufacture antipsychotic drugs. NF has received funds for research, fees, and expenses from several pharmaceutical companies who manufacture antipsychotic drugs and from the Department of Health in England. PH has received support from pharmaceutical companies to attend conferences. He has also received fees for educational lectures to psychiatrists on the psychopharmcology of schizophrenia and on the work described in this paper. PB has received fees for presentations at meetings sponsored by various pharmaceutical companies who manufacture typical and atypical antipsychotics. In addition he is one of the lead investigators of the European schizophrenia cohort funded by Lundbeck.
Further data and members of the
National Schizophrenia Guideline Development Group are available on the
BMJ's website
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(Accepted 3 October 2000)
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