精神分裂症神经内分泌、免疫、自由基代谢与治疗药物的关系

目的 探讨典型,非典型抗精神病药对精神分裂症神经内分泌,免疫,自由基代谢的作用及其与疗效的关系。方法 用固定剂量（利培酮为６ｍｇ／ｄ,氟哌啶醇２０ｍｇ／ｄ,在１周内增至治疗量）利培酮,氟哌啶醇随机,双盲治疗７８例精神分裂症例患者１２周,在治疗前后分别评定阳笥和阴性症状量表（ＰＡＮＳＳ）并测定帕罗西汀激发的神经内分泌试验,白细胞介素２（ＩＬ－２）白细胞介素８（ＩＬ－８）和超氧化物歧化酶（ＳＯＤ）等,     

抗精神病药对老年精神分裂症患者血清催乳素的影响

目的：探讨几种抗精神病药对老年精神分裂症患者血清催乳素（PRL）的影响。方法：随机选取抗精神病药治疗老年精神分裂症患者121例,分别在治疗前后测定血清PRL水平。结果：患者经舒必利、奋乃静、氟哌啶醇和利培酮治疗后血清PRL明显升高,各药物之间以及治疗前后比较差异均有显著性（F=15．95,P〈0．01）。PRL水平的升高与药物剂量呈正相关。氯氮平对PRL水平影响不明显。结论：典型和非典型抗精神病药对老年精神分裂症患者血清PRL水平的影响同样明显,强弱的顺序依次是舒必利、奋乃静、氟哌啶醇和利培酮。     

首发青少年精神分裂症药物疗效的纵向比较

目的　了解利培酮、氯氮平、氯丙嗪、氟哌啶醇 4种抗精神病药物治疗首发青少年精神分裂症患者的近期和远期疗效。方法　将首发青少年精神分裂症 2 36例分成利培酮组、氯氮平组、氟哌啶醇组及氯丙嗪组 ,采用BPRS及TESS在患者首次住院治疗前及治疗后 2、4、6、8周进行评定 ,并观察 4组药物的副反应 ;对 4组患者出院后 3年内进行随访 ,并利用BPRS、TESS及SDSS每年评定 1次。结果　在首次住院中 ,4种抗精神病药物在治疗精神分裂症症状方面的近期疗效基本相同 ,但在药物副作用方面 4组患者有显著差异 ;在 3年随访中 ,4组患者在中断治疗、社会功能恢复等方面也有显著差异。结论　非典型抗精神药物的远期疗效优于典型抗精神病药物 ,提示在治疗青少年精神分裂症患者时可首选利培酮或氯氮平等非典型抗精神病药物     

精神分裂症血清白细胞介素-2测定及其临床意义

目的　探讨首发精神分裂症患者血清白细胞介素 2 (IL 2 )水平及其临床意义。方法　用放射免疫法 (平衡法 )检测 42例首发精神分裂症患者治疗前后血清IL 2含量。并对患者进行阴性和阳性症状量表 (PANSS) ,汉密顿抑郁量表 (HAMD) ,副反应量表(TESS)等评定。结果　首发精神分裂症患者治疗前血清IL 2明显低于正常组 (P <0 0 5 ) ,男女之间无差异 ;精神分裂症治疗前血清IL 2水平Ⅰ型显著低于Ⅱ型 (P <0 0 5 ) ,混合型和Ⅰ型、Ⅱ型之间分别无显著性差异 (P >0 0 5 ) ;氯氮平和利培酮能显著降低血清IL 2水平 (P <0 0 5 ) ,氟哌啶醇治疗前后IL 2改变不明显。治疗前后血清IL 2水平及其变化与首发年龄、病程、PANSS和HAMD评分及减分率、TESS总分均无显著相关 (P >0 0 5 )。结论　血清IL 2降低 ,可能与精神分裂症发病有关 ,并可影响其早期亚型分布。非典型抗精神病药可能通过降低血清IL 2水平达到免疫抑制作用。有必要加强免疫调节剂的针对性治疗     

抗精神病药奥兰平

奥兰平（Ｏｌａｎｚａｐｉｎｅ）是一种不同氟哌啶醇等典型抗精神病药物而十分类似氯氮平的非典型抗精神病药物。它作用于多种受体，对阳性症状的疗效类似氟哌啶醇、利培酮，但对阴性症状、情感症状的疗效卓越，且副作用轻微，尤其是锥体外系副作用缓和，ＴＤ的发生更低，...     

利培酮与氟哌啶醇对女性首发精神分裂症患者血清催乳素水平的影响

目的探讨女性首发精神分裂症患者血清催乳素(PRL)水平,利培酮与氟哌啶醇对PRL水平的影响,以及PRL水平与疗效的关系.方法用酶联免疫法测定66例女性首发精神分裂症患者利培酮与氟哌啶醇治疗前后的PRL水平,与25名正常人对照,并在治疗前后进行阳性和阴性症状量表(PANSS)评定.结果女性首发精神分裂症患者的基础PRL水平与正常对照组无差异;两组患者治疗后血清PRL水平较治疗前显著升高,但两组比较无明显差异;两组患者基础PRL水平与患者年龄、病程、基线PANSS总分及各因子分无明显相关性,与治疗后PANSS总分及各因子分无明显相关性.两组患者PRL增加值与PANSS减分值和各因子减分、药物剂量无明显相关性.结论利培酮和氟哌啶醇都能使女性首发精神分裂症患者PRL水平显著升高,但PRL水平与疾病严重程度及疗效无关.     

精神分裂症患者治疗前后血清白介素-6 和α-干扰素的研究

目的　探讨首发精神分裂症患者血清白细胞介素 6(IL 6)和α 干扰素 (α IFN)水平及抗精神病药对其影响。方法　 68例首发精神分裂症患者随机应用适量的氟哌啶醇、氯氮平和利培酮治疗 1 2周。在治疗前后评定PANSS和TESS量表 ,并采用酶联免疫试验 (ELISA)检测血清IL 6和α INF含量。结果　首发精神分裂症血清IL 6明显高于正常组 (P <0 0 5) ,男女之间无差异 ;血清IL 6与病程 ,PANSS总分均呈正相关 (r=0 62 7,0 592 ,P <0 0 5) ,而与首发年龄 ,阴性症状分、阳性症状分 ,一般病理分 ,TESS总分无相关 (P >0 0 5) ;血清IL 6水平在 3种药物治疗后都显著降低 (P <0 0 5) ,但仍高于正常人群 (P <0 0 5) ,各药间两两比较亦未见显著性差异 (P >0 0 5)。患者治疗前后血清α IFN明显低于正常组 ,治疗前后变化不明显 (P >0 0 5)。结论　精神分裂症发生中IL 6产生增加并反映早期病情严重程度 ,α IFN产生不足。各种抗精神病药具有一定的免疫抑制作用     

利培酮治疗儿童精神分裂症对照研究

目的：比较利培酮和氟哌啶醇治疗儿童精神分裂症的疗效和不良反应。方法：42例儿童精神分裂症患者随机分为利培酮组和氟哌啶醇组，治疗6周。用简明精神病评定量表(BPRS)和副反应量表(TESS)评定疗效和不良反应。结果：利培酮组和氟哌啶醇组BPRS总分在治疗末均显著下降，两组间BPRS总分差异无显著性；两组间疗效差异亦无显著性；利培团组不良反应发生率比氟哌啶醇组明显为低。结论：利培酮治疗儿童精神分裂症安全有效，可作为治疗儿童精神分裂症的首选药物。     

利培酮联合氟哌啶醇与单独氯氮平治疗以阳性症状为主的精神分裂症的效果比较

目的 探讨利培酮短期内联合小剂量氟哌啶醇治疗以阳性症状为主的精神分裂症患者的效果。方法 对80例精神分裂症患者随机分为利培酮联合小剂量氟哌啶醇组(n=40)及单独氯氮平(n=40)治疗组，并进行比较分析，疗程8周。采用简明精神病评定量表(BPRS)、阳性症状评定量表(SAPS)及副反应量表(TESS)分别于疗后第1周、2周、4周、6周、8周末进行评定。结果 利培酮联合小剂量氟哌啶醇组与单独氯氮平治疗组总体疗效相当，能较早、较好的出现治疗效果，而无严重副反应。结论 利培酮短期内联合小剂量氟哌啶醇治疗能有效治疗精神分裂症的阳性症状，值得推荐。     

利培酮治疗老年期精神分裂症双盲对照研究

目的：探讨利培酮治疗老年期精神分裂症的有效性及安全性。方法：分别用利培酮和氟哌啶醇对62例老年期精神分裂症患者进行8周治疗。疗效评定采用阳性与阴性症状量表(PANSS)，不良反应评定用副反应量表(TESS)和Sampson锥体外系反应量表。结果：两组治疗前后比较PANSS总分和各因子分均具有显著差异、两组在治疗第1、2、4、6、8周PANSS总分及各因子分比较差异均无显著性，但利培酮组较氟哌啶醇组在治疗阴性症状方面起效早2周。不良反应震颤、肌强直、活动减退发生率利培酮组显著低于氟哌啶醇组。结论：利培酮和氟哌啶醇均为治疗老年期精神分裂症有效、安全的药物。利培酮治疗阴性症状起效较早，氟哌啶醇锥体外系反应较显著。     

Changes in serum interleukin-2, -6, and -8 levels before and during treatment with risperidone and haloperidol: relationship to outcome in schizophrenia

BACKGROUND: Many studies have indicated that immune cytokines may be involved in the pathophysiology of schizophrenia. Recently, there have been reports that typical and atypical antipsychotic drugs may influence the levels of cytokines or cytokine receptors. The aim of this study was to compare the effect of typical and atypical antipsychotic drugs on serum interleukin-2 (IL-2), interleukin-6 (IL-6), and interleukin-8 (IL-8) and to investigate the relationship between the changes in cytokines and the therapeutic outcome in schizophrenia. METHOD: From April 1996 to August 1997, seventy-eight inpatients with a diagnosis of chronic schizophrenia (DSM-III-R) were randomly assigned to 12 weeks of treatment with 6 mg/day of risperidone or 20 mg/day of haloperidol. Clinical efficacy was determined using the Positive and Negative Syndrome Scale. Serum IL-2 was assayed by radioimmunometric assay, and serum IL-6 and IL-8 concentrations were measured by quantitative enzyme-linked immunosorbent assay in patients and 30 sex- and age-matched normal subjects. RESULTS: Both risperidone and haloperidol reduced the elevated serum IL-2 concentrations in schizophrenia, and no significant difference was noted in the reduction of serum IL-2 concentrations between risperidone and haloperidol treatment. Neither risperidone nor haloperidol showed significant influence on the higher serum IL-6 or IL-8 concentrations in schizophrenia. Correlations between serum IL-2 or IL-8 concentrations at baseline and the therapeutic outcome were observed, demonstrating that patients presenting with low concentrations of serum IL-2 or IL-8 at baseline showed greater improvement and patients presenting with higher serum IL-2 or IL-8 concentrations at baseline showed less improvement after treatment. CONCLUSIONS: Both typical and atypical anti-psychotic drugs may at least partially normalize abnormal immune alterations in schizophrenia. Some immune parameters at baseline may be useful for predicting the neuroleptic response of schizophrenic patients.     

Factors influencing acute weight change in patients with schizophrenia treated with olanzapine, haloperidol, or risperidone

OBJECTIVE: Clinical factors predicting weight change in patients with schizophrenia and related disorders during acute treatment with the antipsychotic drugs olanzapine, risperidone, and haloperidol were sought through retrospective analyses. METHOD: Six-week body-weight data from 2 trials, study 1 comparing olanzapine and haloperidol (N = 1,369) and study 2 olanzapine and risperidone (N = 268), were analyzed. Effects of 8 clinically relevant covariates--therapy, clinical outcome (Brief Psychiatric Rating Scale), baseline body mass index (BBMI), increased appetite, age, gender, race, and dose--on weight were compared. RESULTS: In study 1, olanzapine (vs. haloperidol) therapy, better clinical outcome, lower BBMI, and nonwhite race significantly affected weight gain. Effects of increased appetite and male gender on weight gain were significant for olanzapine but not for haloperidol. In study 2, better clinical outcome, lower BBMI, and younger age significantly affected weight gain. Increased appetite was more frequent during olanzapine treatment than during haloperidol, but not significantly different from risperidone. Significant differences in effect on weight change were found between olanzapine and haloperidol but not between olanzapine and risperidone. No evidence was found that lower antipsychotic drug doses were associated with lower weight gain. CONCLUSION: This report identifies predictive factors of acute weight change in patients with schizophrenia. Similar factors across antipsychotic drugs in predicting greater weight gain included better clinical outcome, low BBMI, and nonwhite race. Factors differing between conventional (haloperidol) and atypical (olanzapine) agents included increased appetite and gender. Choice of atypical antipsychotic drug (olanzapine vs. risperidone) was of minor importance with regard to influence on acute weight gain.     

One-year double-blind study of the neurocognitive efficacy of olanzapine, risperidone, and haloperidol in schizophrenia

Neurocognitive deficits in schizophrenia can reach 1 to 2 standard deviations below healthy controls. The comparative effect of typical and atypical antipsychotic medications on neurocognition is controversial, and based primarily on studies with small samples and large doses of typical comparator medications. The present study assessed neurocognitive efficacy. It was hypothesized that olanzapine treatment would improve neurocognitive deficits to a greater degree than either risperidone or haloperidol treatment. This was a double-blind, randomized, controlled, parallel study with neurocognition assessed at baseline, and 8, 24, and 52 weeks. Per protocol, the haloperidol arm was discontinued. Four hundred and fourteen inpatients or outpatients with schizophrenia and schizoaffective disorder were treated with oral olanzapine (n = 159), risperidone (n = 158), or haloperidol (n = 97). Individual domains (executive function, learning and memory, processing speed, attention/vigilance, verbal working memory, verbal fluency, motor function, and visuospatial ability) were transformed into composite scores and compared between treatment groups. At the 52-week endpoint, neurocognition significantly improved in each group (p < 0.01 for olanzapine and risperidone, p = 0.04 for haloperidol), with no significant differences between groups. Olanzapine- and risperidone-treated patients significantly (p < 0.05) improved on domains of executive function, learning/memory, processing speed, attention/vigilance, verbal working memory, and motor functions. Additionally, risperidone-treated patients improved on domains of visuospatial memory. Haloperidol-treated patients improved only on domains of learning/memory. However, patients able to remain in treatment for the entire 52 weeks benefited more from olanzapine or risperidone treatment than haloperidol treatment.     

Effects of olanzapine, risperidone and haloperidol on prepulse inhibition in schizophrenia patients: a double-blind, randomized controlled trial

Prepulse inhibition (PPI), whereby the startle eyeblink response is inhibited by a relatively weak non-startling stimulus preceding the powerful startle eliciting stimulus, is a measure of sensorimotor gating and has been shown to be deficient in schizophrenia patients. There is considerable interest in whether conventional and/or atypical antipsychotic medications can "normalize" PPI deficits in schizophrenia patients. 51 schizophrenia patients participated in a randomized, double-blind controlled trial on the effects of three commonly-prescribed antipsychotic medications (risperidone, olanzapine, or haloperidol) on PPI, startle habituation, and startle reactivity. Patients were tested at baseline, Week 4 and Week 8. Mixed model regression analyses revealed that olanzapine significantly improved PPI from Week 4 to Week 8, and that at Week 8 patients receiving olanzapine produced significantly greater PPI than those receiving risperidone, but not haloperidol. There were no effects of medication on startle habituation or startle reactivity. These results support the conclusion that olanzapine effectively increased PPI in schizophrenia patients, but that risperidone and haloperidol had no such effects. The results are discussed in terms of animal models, neural substrates, and treatment implications.     

Efficacy of risperidone versus olanzapine in patients with schizophrenia previously on chronic conventional antipsychotic therapy: a switch study

The objective of the study was to examine whether patients with schizophrenia who were judged to be stable on long-term treatment with conventional antipsychotic medications would further benefit from a switch to an atypical antipsychotic drug. Thirty-six subjects with schizophrenia spectrum disorder, on conventional antipsychotic medication therapy for at least 2 years, were randomized in double-blind fashion to risperidone versus olanzapine. Patients were titrated up to 6 mg risperidone or 15 mg olanzapine as tolerated, followed by tapering and discontinuation of conventional antipsychotic medication. Atypical antipsychotic agents were then administered alone (monotherapy) for 12 weeks. Efficacy and tolerability were assessed using the Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression Scale, and Simpson Angus Scale. Body weight was measured at each visit. Both treatment groups exhibited marked and similar improvement in the total PANSS score from baseline to study endpoint (22 weeks) [risperidone: baseline=59.3 (SE 3.1), 22 weeks=44.3 (SE 2.3) (p<0.001); olanzapine: baseline=55.9 (SE 3.3), 22 weeks=46.9 (SE 3.2) (p<0.001). Both groups also exhibited significant reductions in PANSS factor scores for positive and negative symptoms and disorganized thoughts. Only risperidone-treated patients exhibited significant decreases in uncontrolled hostility/excitement and anxiety and depression. Of note, while positive factor scores exhibited the majority of change within the first 10 weeks, negative factor scores continued to decline significantly in both treatment groups throughout the study. Tolerability assessments did not differ between groups. The results indicate that both atypical antipsychotic medications provided significant additional improvement in symptom severity in patients with schizophrenia previously on conventional antipsychotic agents.     

Effects of atypical antipsychotics on the syndromal profile in treatment-resistant schizophrenia

BACKGROUND: There has been considerable support for the observation that atypical antipsychotics have a broader range of therapeutic effects than traditional antipsychotics. We are exploring whether this expanded clinical efficacy can also be seen in patients with treatment-resistant schizophrenia. METHOD: The subjects were 157 treatment-resistant inpatients diagnosed with DSM-IV schizophrenia or schizoaffective disorder. They were randomly assigned to treatment with clozapine, olanzapine, risperidone, or haloperidol in a 14-week double-blind trial and rated with a standard measure of clinical antipsychotic efficacy (Positive and Negative Syndrome Scale [PANSS]). Factor analysis at baseline and endpoint together with changes in 5 PANSS-derived factors were examined. Data were gathered from June 1996 to December 1999. RESULTS: The underlying PANSS factor structure, as indicated by the factor loadings, was essentially identical at baseline and endpoint. At baseline, the excitement factor was followed by the positive, negative, cognitive, and depression/anxiety factors, explaining 49.4% of the total variance. At endpoint, the positive factor was followed by the negative, excitement, cognitive, and depression/anxiety factors, explaining 55.5% of the total variance. The endpoint data indicated statistically significant (p <.05) improvements over time on the positive factor for all 3 atypicals, but not for haloperidol. The negative factor showed significant improvement for clozapine and olanzapine, with significant worsening for haloperidol. Clozapine, olanzapine, and risperidone were superior to haloperidol on the negative factor, while clozapine was also superior to risperidone. The cognitive factor showed significant improvement for all atypicals, as did the depression/anxiety factor. Only clozapine showed improvement on the excitement factor and was superior to both haloperidol and risperidone. CONCLUSIONS: Treatment with atypical antipsychotics did not substantially change the underlying PANSS 5-factor structure. However, antipsychotic treatment with all 3 atypical medications was associated with significant improvements on 3 of 5 syndromal domains (positive, cognitive, and depression/anxiety) of schizophrenia. Clozapine and olanzapine also showed improvement on the negative factor. Only clozapine was associated with improvement on the excitement domain. This finding confirms that atypicals are associated with improvement of an expanded spectrum of symptoms in treatment-resistant patients.     

Long-term effects of risperidone versus haloperidol on verbal memory, attention, and symptomatology in schizophrenia.

There is evidence in the literature that cognitive functions in schizophrenia (SC) may be improved by atypical neuroleptics (NLPs) in contrast to typical medication, but there is still controversy regarding this apparent superiority of atypical drugs. In this study, we assessed the differential effects of risperidone and haloperidol on verbal memory, attention, and psychiatric symptoms in SC. The performance of 28 SC participants, randomly assigned to risperidone (2-6 mg/day) or haloperidol (2-40 mg/day), was compared with that of healthy controls. The California Verbal Learning Test (CVLT), the d2 Cancellation Test, and the Positive and Negative Symptoms Scale were administered at baseline and 3, 6, and 12 months. Relative to controls, all SC participants showed markedly impaired verbal memory and processing speed at each assessment period. There was no differential effect between the two NLPs on CVLT and d2 performance. However, risperidone was more effective than haloperidol in reducing psychiatric symptoms. Improvement in symptom severity was not associated with improvement in neurocognitive performance on these specific tests. Neither conventional nor atypical neuroleptic medications improved neurocognitive functioning over a 12-month follow-up, suggesting that psychopathological improvement under risperidone is independent of cognitive function.     

Clozapine, olanzapine, risperidone, and haloperidol in the treatment of patients with chronic schizophrenia and schizoaffective disorder

OBJECTIVE: The authors compared the efficacy and safety of three atypical antipsychotics (clozapine, olanzapine, and risperidone) with one another and with haloperidol in the treatment of patients with chronic schizophrenia or schizoaffective disorder. METHOD: In a double-blind trial, 157 inpatients with a history of suboptimal treatment response were randomly assigned to treatment with clozapine, olanzapine, risperidone, or haloperidol for 14 weeks (an 8-week escalation and fixed-dose period followed by a 6-week variable-dose period). RESULTS: Clozapine, risperidone, and olanzapine (but not haloperidol) resulted in statistically significant improvements in total score on the Positive and Negative Syndrome Scale. Improvements seen in total and negative symptom scores with clozapine and olanzapine were superior to haloperidol. The atypical drugs, particularly olanzapine and clozapine, were associated with weight gain. CONCLUSIONS: The effects of atypical antipsychotics in this population were statistically significant but clinically modest. The overall pattern of results suggests that clozapine and olanzapine have similar general antipsychotic efficacy and that risperidone may be somewhat less effective. Clozapine was the most effective treatment for negative symptoms. However, the differences among treatments were small.     

Effectiveness of antipsychotic treatments for schizophrenia: interim 6-month analysis from a prospective observational study (IC-SOHO) comparing olanzapine, quetiapine, risperidone, and haloperidol

BACKGROUND: The Intercontinental Schizophrenia Outpatient Health Outcomes (IC-SOHO) study was designed to provide information regarding use and outcome of antipsychotic treatments in a large, diverse population in real practice settings. METHOD: Outpatients with schizophrenia (ICD-10 or DSM-IV) who initiated or changed to a new antipsychotic entered this 3-year, naturalistic, prospective observational study. Four monotherapy treatment groups were defined according to the antipsychotic prescribed at baseline, namely olanzapine, risperidone, quetiapine, and haloperidol. Efficacy was assessed using the Clinical Global Impressions-Severity of Illness rating scale (CGI-S), inclusive of subscales for positive, negative, depressive, and cognitive symptoms. Tolerability was assessed by adverse event questionnaires and weight measurements. Six-month findings are described. RESULTS: At baseline, 5833 participants were prescribed monotherapy and the mean severity of illness was moderate to marked (CGI-S). At 6 months, olanzapine resulted in significantly greater improvements in overall, positive, negative, depressive, and cognitive symptoms compared with quetiapine, risperidone or haloperidol (p <.001). Improvements in overall, negative, and cognitive symptoms were significantly higher for risperidone compared with haloperidol (p <.001), whereas improvements across all symptoms were comparable for quetiapine and haloperidol. Extra-pyramidal symptoms and tardive dyskinesia decreased compared with baseline in the olanzapine, quetiapine, and risperidone groups but increased in the haloperidol group (p <.001, likelihood of extrapyramidal symptoms with haloperidol compared with olanzapine, quetiapine, or risperidone). Sexual function adverse events were most prominent in the haloperidol and risperidone treatment groups. Weight change was significantly greater for olanzapine compared with the other antipsychotics (p <.001). CONCLUSION: Our results support the previously reported positive impact of atypical antipsychotics, particularly olanzapine, in patients with schizophrenia.     

Safety and efficacy of long-acting risperidone in schizophrenia: a 12-week, multicenter, open-label study in stable patients switched from typical and atypical oral antipsychotics

BACKGROUND: The safety and efficacy of the first long-acting injectable atypical antipsychotic, risperidone, were assessed in stable patients with schizophrenia switched from oral antipsychotic medications. METHOD: Data were collected between July 1, 2001, and October 25, 2002. The study population included patients from clinics, hospitals, and physicians' offices. After a 4-week run-in period, symptomatically stable patients with schizophrenia (DSM-IV) who had been taking haloperidol (N = 46), quetiapine (N = 45), or olanzapine (N = 50) received 25 mg of long-acting risperidone. The oral antipsychotics were continued for 3 weeks after the first injection of long-acting risperidone. Injections were administered every 2 weeks at 25 mg up to a maximum dose of 50 mg for 12 weeks in this multicenter, open-label study. RESULTS: Long-acting risperidone was well tolerated. Of the 141 patients who participated in the study, the most frequently reported adverse events were insomnia (16%), headache (15%), psychosis (11%), and agitation (11%). The mean increase in body weight was 0.4 kg. No other clinically relevant laboratory abnormalities or significant electrocardiogram changes were observed during the 12-week treatment. Extrapyramidal Symptom Rating Scale total scores were reduced during treatment with long-acting risperidone. Improvements in symptoms of schizophrenia were observed with long-acting risperidone at week 4 and continued through the 12-week treatment with significant reductions in total Positive and Negative Syndrome Scale (PANSS) scores at week 8 (-2.5, p <.01) and week 12 (-3.9, p <.001). At endpoint, 37% (50/135) of these stable patients were rated as clinically improved (> or = 20% decrease in PANSS total scores). CONCLUSIONS: Switching treatment from oral antipsychotics to long-acting risperidone without an intervening period of oral risperidone was safe and well tolerated. Long-acting risperidone also significantly reduced the severity of symptoms in these stable patients with schizophrenia.