***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 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 Treating schizophrenia is expensive . Preventing rehospitalization of patients with schizophrenia provides an attractive opportunity for cost savings , especially for patients with ' revolving-door ' or multiple-episode schizophrenia . Reducing the occurrence of extrapyramidal symptoms and other adverse events associated with st and ard antipsychotic agents may increase compliance and reduce the rate of rehospitalization of patients with schizophrenia .  Quetiapine ( ' Seroquel ' , ICI 204,636 , Zeneca Pharmaceuticals ) is a new dibenzothiazepine antipsychotic agent with a low propensity for extrapyramidal symptoms . We describe here a unique methodology to compare quetiapine with usual-care medications in real-world treatment setting s. The trial objective is to determine if therapy with this new atypical antipsychotic agent can reduce the rate of rehospitalization and , therefore , treatment costs . Using two secondary medical-cl aims data bases , we defined the minimal threshold for revolving-door status as 1.0 admission per year ; this definition allows our trial to focus on the sub population of schizophrenic patients with the greatest potential for cost savings by either the new atypical antipsychotic quetiapine or usual-care therapy . We describe here the approach used in our trial Abstract We investigated the striatal dopamine-2 ( D2 ) receptor occupancy caused by different antipsychotic substances in 18 psychotic patients ( 16 with schizophrenic and two with schizoaffective disorder according to DSM-IV ) with single photon emission computed tomography (  SPECT  ) using 123I-iodobenzamide ( IBZM ) as tracer substance . Four patients were treated with the novel antipsychotic compound quetiapine ( 300–700 mg/day ) , six with clozapine ( 300–600 mg/ day ) and eight with haloperidol ( 10–20 mg/day ) . They were compared with eight healthy controls . Measurement of S/F ratios and consecutive calculation of D2 receptor occupancy revealed a significantly lower striatal D2 occupancy rate with quetiapine and clozapine in comparison to haloperidol . In correspondence with the low striatal D2 receptor occupancy rates and again in contrast to the haloperidol treatment group , there were no extrapyramidal motor side-effects ( EPS ) in the quetiapine and clozapine treatment groups . Therefore , the reported data support the position that quetiapine can be considered to be an atypical antipsychotic substance due to its relatively weak striatal D2 receptor blocking property and therefore its low propensity to induce EPS 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 with quetiapine 150 mg tid ( n = 209 ) , 225 mg bd ( n = 200 ) , or a comparator dose of 25 mg bd ( n = 209 ) . At day 42 , the last day of r and omized treatment and the primary timepoint for efficacy , quetiapine 450 mg/day was more effective than 50 mg/day : 225 mg bd was consistently superior to 25 mg bd in all measures of efficacy ( total BPRS , P = 0.006 ; CGI severity , CGI improvement and SANS , P < 0.03 ) , and 150 mg tid was statistically significantly superior to 25 mg bd with respect to BPRS total score ( P = 0.05 ) . The 225 mg bd and 150 mg tid groups were not significantly different from each other with respect to any efficacy measure . Quetiapine was generally well tolerated . Extrapyramidal symptom ( EPS ) adverse events were generally rare , and occurred with similar frequencies in the two 450 mg/day groups . Quetiapine was not associated with sustained increases in plasma prolactin at any dose . These data support the atypical profile developed from pre clinical studies and show that quetiapine is an effective , well tolerated antipsychotic that can be given twice daily OBJECTIVE To assess the efficacy of quetiapine , a recently introduced second generation antipsychotic medication , in reducing cognitive impairment in patients with schizophrenia . DESIGN Prospect i ve , r and omized , double-blind clinical trial . PATIENTS 25 patients who met the Diagnostic and Statistical Manual of Mental Disorders , fourth edition , ( DSM-IV ) criteria for schizophrenia were recruited from 3 Canadian hospitals . INTERVENTION AND OUTCOME MEASURES After a 48-hour washout period , 25 patients with schizophrenia were r and omly assigned to double-blind treatment with quetiapine or haloperidol for 6 months and evaluated with rating scales for psychotic symptoms , mood and extrapyramidal side effects , as well as st and ardized neuropsychological measures sensitive to 6 cognitive domains : fine motor skill , attention span , verbal reasoning and fluency , visuospatial construction and fluency , executive skills and visuomotor tracking , and immediate recall of verbal and nonverbal material s. The measures were repeated 8 weeks and 6 months after treatment was initiated . RESULTS Quetiapine improved psychosis and mood without inducing extrapyramidal symptoms . Quetiapine also had beneficial effects on cognitive skills , particularly verbal reasoning and fluency skills and immediate recall , with additional improvements on executive skills and visuomotor tracking and on the average of the 6 cognitive domains with sustained treatment . Patients taking haloperidol showed improvements in general clinical status , but no specific improvements on the positive syndrome , the negative syndrome , depression ratings or cognitive skills . CONCLUSIONS These preliminary results support the potential value of quetiapine for improving cognitive impairment in patients with schizophrenia and emphasize the importance of further research with this promising atypical antipsychotic In a double-blind study , 135 in patients with a diagnosis of chronic schizophrenia were r and omly assigned to 8 weeks of treatment with one of six parallel treatments : risperidone ( a new central 5-hydroxytryptamine2 and dopamine D2 antagonist ) , 2 , 6 , 10 , 16 mg/day ; haloperidol , 20 mg/day ; or placebo , after a single-blind placebo washout period . Doses were increased in fixed increments up to a fixed maintenance dose reached after 1 week . On the Clinical Global Impression-Severity of Illness and Improvement , all active medications were superior to placebo except for risperidone ( 2 mg ) on the Clinical Global Impression-Improvement . On the total Positive and Negative Syndrome Scale ( PANSS ) score and positive subscale , superiority to placebo was observed for all treatment groups except for haloperidol and risperidone ( 2 mg ) , which tended to be superior to placebo on total PANSS and the positive subscale , respectively . On the PANSS negative subscale , only risperidone ( 6 mg/day ) was significantly better than placebo . Risperidone ( 6 mg ) was superior to haloperidol on the total PANSS , General Psychopathology , and Brief Psychiatric Rating Scale subscales . Although there was a linear increase in parkinsonism with increasing risperidone dosage , there were no statistically significant differences between risperidone ( 2 , 6 , and 16 mg/day ) and placebo . At doses of 6 to 16 mg , risperidone displayed a marked antidyskinetic effect compared with placebo . This effect was more pronounced in patients with severe dyskinesia . By contrast , haloperidol produced significantly more parkinsonism than placebo and risperidone ( 2 , 6 and 16 mg ) , with no effect on tardive dyskinesia . These data suggest that risperidone , at the optimal therapeutic dose of 6 mg/day , produced significant improvement in both positive and negative symptoms without an increase in drug-induced parkinsonian symptoms and with a significant beneficial effect on tardive dyskinesia The treatment of schizophrenic patients who fail to respond to adequate trials of neuroleptics is a major challenge . Clo 
    Output:
    
Data incorporating considerable assumptions about the many people who left early suggest that global state and psychotic symptoms - both positive and negative - may be more helped by quetiapine than placebo .
While the incidences of extrapyramidal side effects are not different between quetiapine and placebo , side effects such as dizziness and dry mouth are more prevalent in the  quetiapine  treated group .
Quetiapine is as potent as chlorpromazine and haloperidol as regards global and mental state but it may cause higher incidences of dry mouth and sleepiness .
Extrapyramidal side effects are the same as those of chlorpromazine but may be less than haloperidol .
There are no clear differences between high and low dose groups in respect of extrapyramidal side effects .