***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND The few published direct comparative studies of the tolerability and efficacy of atypical antipsychotic agents were performed in relatively homogeneous population s that may not be typical of patients seen in clinical practice . OBJECTIVE The Quetiapine Experience with Safety and Tolerability ( QUEST ) study compared the relative safety , tolerability , and efficacy of quetiapine and risperidone in out patients with a broad range of psychotic symptoms . METHODS This was a multicenter , 4-month , open-label , r and omized clinical trial . Patients were r and omized in a 3:1 ratio to receive quetiapine or risperidone . Doses were adjusted to maximize efficacy and to minimize adverse events . Extrapyramidal symptoms ( EPS ) were assessed with an EPS checklist ; adverse events were recorded . Efficacy was assessed using the Clinical Global Impression ( CGI ) scale , Positive and Negative Symptom Scale ( PANSS ) , and Hamilton Rating Scale for Depression ( HAM-D ) . RESULTS A total of 728 patients were r and omized , 553 to quetiapine and 175 to risperidone .  Mean prescribed doses over the study period were 253.9 mg/d quetiapine and 4.4 mg/d risperidone . At the end of 4 months , EPS declined in both treatment groups , but quetiapine-treated patients were significantly less likely to require dose adjustment or concurrent anti-EPS medication ( P < 0.001 ) . The most common adverse events in the quetiapine and risperidone groups were somnolence ( 31.3 % and 15.4 % , respectively ) , dry mouth ( 14.5 % and 6.9 % ) , and dizziness ( 12.7 % and 6.9 % ) . Overall , tolerance to side effects with the 2 drugs , measured by dropout rates , was comparable . At each visit , a higher percentage of quetiapine-treated patients showed improvement on the CGI scale , but there were no significant between-group differences on the PANSS . At end point , quetiapine-treated patients had significantly lower HAM-D scores ( P = 0.028 ) . CONCLUSIONS The results of this study suggest that quetiapine is as effective as risperidone for the treatment of psychotic symptoms , is more effective for depressive symptoms , may have a more favorable EPS profile , and has comparable overall tolerability BACKGROUND The purpose of this investigation was to test the efficacy of novel antipsychotic medications in the treatment of  cognitive impairment in early phase schizophrenia . METHODS Sixty-five patients in this multicenter double-blind study were r and omly assigned to olanzapine ( 5 - 20 mg ) , risperidone ( 4 - 10 mg ) , or haloperidol ( 5 - 20 mg ) . St and ard measures of clinical and motor syndromes were administered , as well as a comprehensive battery of tests to assess ( 1 ) motor skills , ( 2 ) attention span , ( 3 ) verbal fluency and reasoning , ( 4 ) nonverbal fluency and construction , ( 5 ) executive skills , and ( 6 ) immediate recall at baseline and after 6 , 30 , and 54 weeks of treatment . RESULTS The general cognitive index derived from the 6 domain scores revealed a significantly greater benefit from treatment with olanzapine relative to haloperidol and olanzapine relative to risperidone , but no significant difference was shown between risperidone and haloperidol . The improvement related to olanzapine was apparent after 6 weeks and enhanced after 30 and 54 weeks of treatment . Exploratory within-group analyses of the 6 cognitive domains after a conservative Bonferroni adjustment revealed a significant improvement with olanzapine only on the immediate recall domain , and similar analyses of the 17 individual tests revealed a significant improvement with olanzapine only on the Hooper Visual Organization Test . CONCLUSIONS These data suggest that olanzapine has some superior cognitive benefits relative to haloperidol and risperidone . A larger sample replication study is necessary to confirm and generalize the observations of this study and begin evaluation of the implication s of this change to cerebral function and quality of life for people with schizophrenia BACKGROUND Quetiapine ( ICI 204,636 , ' Seroquel ' ) is a new atypical antipsychotic agent with a similar binding profile to the original atypical antipsychotic , clozapine . Its clinical efficacy has already been demonstrated at multiple fixed doses ( 150 - 750 mg/day ) and has been suggested to be comparable with haloperidol ( 12 mg/day ) . METHODS This international , 6-week , multicentre , double-blind , r and omized , parallel-group trial compared quetiapine with haloperidol ( 455 mg and 8 mg mean total daily doses , respectively ) in 448 hospitalized patients with acute exacerbation of chronic or subchronic schizophrenia ( DSM-III-R ) , in order to establish their equivalence in terms of efficacy , and the nature of their tolerability profiles , especially in terms of extrapyramidal symptoms ( EPS ) and serum prolactin levels . RESULTS Both quetiapine and haloperidol produced a clear reduction in the Positive and Negative Syndrome Scale ( PANSS ) scores and Clinical Global Impression ( CGI ) Severity of Illness and Global Improvement scores . At day 42 , the PANSS total score was reduced by -18.7+/-1.63 in the quetiapine group , and -22.1+/-1.63 in the haloperidol group ( P = 0.13 , between-treatment ) . Quetiapine was better tolerated than haloperidol in terms of EPS as demonstrated by the significant differences in the Simpson Scale and Abnormal Involuntary Movement Scale scores ( P < 0.05 ) . Although patients in both groups had elevated serum prolactin concentrations at baseline , mean serum prolactin concentration decreased ( by 16.5 microg/l ) in quetiapine-treated patients , yet increased ( by 5.9 microg/l ) in patients treated with haloperidol . CONCLUSION Quetiapine is an effective and well tolerated antipsychotic of comparable efficacy to haloperidol and lacks the latter compound 's effect on prolactin and EPS Schizophrenia is a devastating psychiatric disorder . Clozapine has long been the gold st and ard for treatment of patients with treatment-resistant schizophrenia ;  however , some patients are only partially responsive to clozapine treatment . Augmentation of clozapine treatment might enhance its effectiveness in partial responders , but only a few studies have investigated possible augmentation strategies . This study compared the effectiveness and tolerability of the combination of amisulpride and clozapine with the combination of quetiapine and clozapine in patients who were only partially responsive to clozapine monotherapy . Fifty-six treatment-resistant patients who were partially responsive to clozapine  were r and omly assigned to receive amisulpride or quetiapine along with an ongoing stable dose of clozapine .  Fifty patients completed the study . Patients were evaluated at baseline and at the first , third , sixth , and eighth weeks . Efficacy measures consisted of the Brief Psychiatric Rating Scale ( BPRS ) , the Scale for the Assessment of Negative Symptoms ( SANS ) , the Scale for the Assessment of Positive Symptoms ( SAPS ) , and the Clinical Global Impression ( CGI ) scale . Tolerability and adverse effects were assessed with the Udvalg for Kliniske Undersogelser ( UKU ) Side Effect Rating Scale and the Simpson Angus Scale ( SAS ) . A substantial improvement occurred in both groups by the end of the eighth week ; however , the improvement associated with amisulpride was significantly greater than that seen with quetiapine . This difference was noted as early as the third week of follow-up in terms of CGI scores , and by the sixth week with regard to BPRS , SANS , and SAPS scores . Both drugs were well tolerated , as measured by UKU and SAS . Improvement favoring clozapine+amisulpride could be attributed to the selective D2/D3 binding property of amisulpride , which had an additional effect in improving symptoms of schizophrenia . The authors concluded that amisulpride seems to be effective and well tolerated for augmentation purpose s in clozapine-resistant patients OBJECTIVE The authors assessed the efficacy and safety of the first long-acting atypical antipsychotic ( long-acting injectable risperidone ) in patients with schizophrenia . METHOD In a 12-week , multicenter , double-blind , r and omized study , patients received intramuscular injections every 2 weeks of placebo or long-acting risperidone ( 25 mg , 50 mg , or 75 mg ) . The primary measure of efficacy was the change in total score on the Positive and Negative Syndrome Scale . RESULTS Of the 554 patients who were enrolled , 400 entered the double-blind study , and 370 received at least one postbaseline assessment .  Mean changes in score of -6.2 , -8.5 , and -7.4 on the Positive and Negative Syndrome Scale were seen at endpoint for the 25- , 50- , and 75-mg risperidone groups , respectively ; all three change scores were significantly different from that seen with placebo ( + 2.6 ) . Improvements in positive and negative symptoms were also significantly greater in patients receiving risperidone . Long-acting risperidone was well tolerated . Adverse events related to extrapyramidal symptoms were spontaneously reported by 13 % of patients receiving placebo and 10 % of patients in the 25-mg risperidone group , with higher rates in the 50-mg and 75-mg groups . Severity of extrapyramidal symptoms was mild at baseline and throughout the trial in each treatment group . Mean weight changes were small in the 25- , 50- , and 75-mg risperidone groups ( 0.5 kg , 1.2 kg , and 1.9 kg , respectively ) . Injection site pain was rated as low by the patients , consistent with the investigators ' pain ratings . CONCLUSIONS Long-acting injectable risperidone was efficacious and well tolerated and provides both clinicians and patients with a new mode of treatment that can improve the outcome of long-term therapy BACKGROUND The treatment of schizophrenia with multiple antipsychotic drugs is common , but the benefits and risks are not known . METHODS In a r and omized , double-blind study , we evaluated patients with schizophrenia and a poor response to treatment with clozapine .  The patients continued to take clozapine and were r and omly assigned to receive eight weeks of daily augmentation with 3 mg of risperidone or with placebo . This course of treatment was followed by an optional 18 weeks of augmentation with risperidone . The primary outcome was reduction in the total score for severity of symptoms on the Positive and Negative Syndrome Scale ( PANSS ) . The secondary outcomes included cognitive functioning . RESULTS A total of 68 patients were r and omly assigned to treatment . In the double-blind phase , the mean total score for the severity of symptoms decreased from baseline to eight weeks in both the risperidone and the placebo groups . There was no statistically significant difference in symptomatic benefit between augmentation with risperidone and placebo : 9 of 34 patients receiving placebo and 6 of 34 receiving risperidone responded to treatment ( P=0.38 ) . The mean difference in the change in PANSS scores from baseline to eight weeks between those receiving risperidone and those receiving placebo was 0.1 ( 95 percent confidence interval , -7.3 to 7.0 ) . The verbal working-memory index showed a small decline in the risperidone group and a small improvement in the placebo group ( P=0.02 for the comparison between the two groups in the change from baseline ) . The increase in fasting blood glucose levels was mildly greater in the risperidone group than in the placebo group ( 16.2 vs. 1.8 mg per deciliter [ 0.90 vs. 0.10 mmol per liter ] , P=0.04 ) . The incidence and severity of other side effects did not differ between the two groups . CONCLUSIONS In this short-term study , the addition of risperidone to clozapine did not improve symptoms in patients with severe schizophrenia . ( Clinical Trials.gov number , NCT00272584 ) Abstract Quetiapine ( Seroquel , ICI 204,636 ) is an atypical antipsychotic that is effective in the treatment of both positive and negative symptoms of schizophrenia , and has a low propensity to cause extrapyramidal symptoms . The compound has a relatively short plasma elimination half-life ( approximately 7 h ) . However , since dopamine D2 receptor occupancies correlate poorly with plasma concentrations of antipsychotics , plasma elimination half-life may not predict either duration of clinical effect or dosing frequency . Accordingly , the efficacy and tolerability of three dosing regimens ( 450 mg/day given in two or three divided doses daily , and 50 mg/day given twice daily ) were compared in a 6-week , double-blind , r and omized , multicentre , parallel-group study . The study recruited hospitalized men and women aged 18–65 years meeting DSM-IIIR criteria for acute exacerbation of chronic or subchronic schizophrenia . Six hundred and eighteen patients were r and omly assigned to treatment 
    Output:
    
The data generally showed minor differences between the atypical antipsychotics evaluated and typical antipsychotics , regarding improvement in disease symptoms , despite better adherence to treatment with atypical antipsychotics .
Risperidone was specifically evaluated in patients with RS in one of the systematic review s included , with favorable outcomes , but without definitive superiority compared with other drugs of proven efficacy , like amisulpride , clozapine and olanzapine .
The findings underscore the difficulty in treating these patients , with high dropout rates and treatment patterns of modest improvement in assessment s of effectiveness .
Atypical antipsychotics have advantages over typical antipsychotics mainly through their better safety profile , which leads to better adherence to treatment .