No abstract

In treatment-resistant schizophrenia, clozapine is considered the standard treatment. However, clozapine use has restrictions owing to its many adverse effects. Moreover, an increasing number of randomized clinical trials (RCTs) of other antipsychotics have been published. OBJECTIVE To integrate all the randomized evidence from the available antipsychotics used for treatment-resistant schizophrenia by performing a network meta-analysis. DATA SOURCES MEDLINE, EMBASE, Biosis, PsycINFO, PubMed, Cochrane Central Register of Controlled Trials, World Health Organization International Trial Registry, and clinicaltrials.gov were searched up to June 30, 2014. STUDY SELECTION At least 2 independent reviewers selected published and unpublished single-and double-blind RCTs in treatment-resistant schizophrenia (any study-defined criterion) that compared any antipsychotic (at any dose and in any form of administration) with another antipsychotic or placebo. DATA EXTRACTION AND SYNTHESIS At least 2 independent reviewers extracted all data into standard forms and assessed the quality of all included trials with the Cochrane Collaboration's risk-of-bias tool. Data were pooled using a random-effects model in a Bayesian setting. MAIN OUTCOMES AND MEASURES The primary outcome was efficacy as measured by overall change in symptoms of schizophrenia. Secondary outcomes included change in positive and negative symptoms of schizophrenia, categorical response to treatment, dropouts for any reason and for inefficacy of treatment, and important adverse events. RESULTS Forty blinded RCTs with 5172 unique participants (71.5% men; mean [SD] age, 38.8 [3.7] years) were included in the analysis. Few significant differences were found in all outcomes. In the primary outcome (reported as standardized mean difference; 95% credible interval), olanzapine was more effective than quetiapine (−0.29; −0.56 to −0.02), haloperidol (−0. 29; −0.44 to −0.13), and sertindole (−0.46; −0.80 to −0.06); clozapine was more effective than haloperidol (−0.22; −0.38 to −0.07) and sertindole (−0.40; −0.74 to −0.04); and risperidone was more effective than sertindole (−0.32; −0.63 to −0.01). A pattern of superiority for olanzapine, clozapine, and risperidone was seen in other efficacy outcomes, but results were not consistent and effect sizes were usually small. In addition, relatively few RCTs were available for antipsychotics other than clozapine, haloperidol, olanzapine, and risperidone. The most surprising finding was that clozapine was not significantly better than most other drugs. CONCLUSIONS AND RELEVANCE Insufficient evidence exists on which antipsychotic is more efficacious for patients with treatment-resistant schizophrenia, and blinded RCTs-in contrast to unblinded, randomized effectiveness studies-provide little evidence of the superiority of clozapine compared with other second-generation antipsychotics. Future clozapine studies with high doses and patients with extremely treatment-refractory schizophrenia might be most promising to change the current evid...

Analysis of primary outcomes (depressive and negative symptoms) suggests small, beneficial effects of adjunctive antidepressants. It would appear that this augmentation can be accomplished with a low risk of exacerbation of psychosis and adverse effects. However, secondary and subgroup analyses should be interpreted cautiously and considered exploratory.

The vastness of clinical data and the progressing specialization of medical knowledge may lead to misinterpretation of medication efficacy. To show a realistic perspective on drug efficacy we present meta-analyses on some of the most commonly used pharmacological interventions. For each pharmacological intervention we present statistical indexes (absolute risk or response difference, percentage response ratio, mean difference, standardized mean difference) that are often used to represent efficacy. We found that some of the medications have relatively low effect sizes with only 11 out of 17 of them showing a minimal clinically important difference. Efficacy was often established based on surrogate outcomes and not the more relevant patient-oriented outcomes. As the interpretation of the efficacy of medication is complex, more training for physicians might be needed to get a more realistic view of drug efficacy. That could help prevent harmful overtreatment and reinforce an evidence-based, but personalized medicine.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-015-0494-1) contains supplementary material, which is available to authorized users.

There is limited evidence, based on a number of trials, that the augmentation of antipsychotics with valproate may be effective for overall clinical response, and also for specific symptoms, especially in terms of excitement and aggression. However, this evidence was entirely based on open RCTs. Moreover, valproate was associated with a number of adverse events among which sedation and dizziness appeared significantly more frequently than in the control groups. Further randomised studies which are blinded are necessary before any clear recommendation can be made. Ideally these would focus on people with schizophrenia and aggression, on those with treatment-resistant forms of the illness and on those with schizoaffective disorders.

The evidence base for the use of lithium in schizophrenia is limited to 22 studies of overall low methodological quality. There is no randomised trial-based evidence that lithium on its own is an effective treatment for people with schizophrenia. There is some GRADE low quality evidence that augmentation of antipsychotics with lithium is effective, but the effects are not significant when more prone-to-bias open RCTs are excluded. Nevertheless, further large and well-designed trials are justified. These should concentrate on two target groups: (1) people with no affective symptoms, so that trialists can determine whether lithium has an effect on the core symptoms of schizophrenia, and (2) people with schizoaffective disorders for whom lithium is widely used in clinical practice, although there is no evidence to support this use.

BackgroundAs the number of systematic reviews is growing rapidly, we systematically investigate whether meta-analyses published in leading medical journals present an outline of available evidence by referring to previous meta-analyses and systematic reviews.MethodsWe searched PubMed for recent meta-analyses of pharmacological treatments published in high impact factor journals. Previous systematic reviews and meta-analyses were identified with electronic searches of keywords and by searching reference sections. We analyzed the number of meta-analyses and systematic reviews that were cited, described and discussed in each recent meta-analysis. Moreover, we investigated publication characteristics that potentially influence the referencing practices.ResultsWe identified 52 recent meta-analyses and 242 previous meta-analyses on the same topics. Of these, 66% of identified previous meta-analyses were cited, 36% described, and only 20% discussed by recent meta-analyses. The probability of citing a previous meta-analysis was positively associated with its publication in a journal with a higher impact factor (odds ratio, 1.49; 95% confidence interval, 1.06 to 2.10) and more recent publication year (odds ratio, 1.19; 95% confidence interval 1.03 to 1.37). Additionally, the probability of a previous study being described by the recent meta-analysis was inversely associated with the concordance of results (odds ratio, 0.38; 95% confidence interval, 0.17 to 0.88), and the probability of being discussed was increased for previous studies that employed meta-analytic methods (odds ratio, 32.36; 95% confidence interval, 2.00 to 522.85).ConclusionsMeta-analyses on pharmacological treatments do not consistently refer to and discuss findings of previous meta-analyses on the same topic. Such neglect can lead to research waste and be confusing for readers. Journals should make the discussion of related meta-analyses mandatory.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-015-0317-4) contains supplementary material, which is available to authorized users.

Background Many people with schizophrenia do not achieve a satisfactory treatment response with just antipsychotic drug treatment and various adjunct medications are used to promote additional response. The antiepileptic carbamazepine is one such drug. Objectives To evaluate the effects of carbamazepine and its derivatives for the treatment of schizophrenia and related psychoses.