Adherence to Background Antipsychotic and Pimavanserin in Patients with Schizophrenia: Post Hoc Analyses from the ENHANCE and ADVANCE Studies.

Background: In patients with schizophrenia, study design to optimize adherence and objective measurement of adherence is critical for interpreting results. Two randomized, double-blind studies evaluating adjunctive pimavanserin in patients with schizophrenia who received stable antipsychotic treatment included measures to encourage and assess treatment adherence. Objective: This post hoc analysis evaluated adherence levels achieved in the Phase III ENHANCE study (NCT02970292) and the Phase II ADVANCE study (NCT02970305). Methods: Blood levels of participants receiving adjunctive treatment with pimavanserin or placebo added to their ongoing antipsychotic medication were tested and evaluated regularly throughout both studies. For both the background antipsychotic and pimavanserin, treatment adherence was defined as a blood sample test result above the lower limit of quantification. Results: Overall, 392 of 633 screened patients and 403 of 608 screened patients were in the safety populations in ENHANCE and ADVANCE, respectively. In ENHANCE, at weeks 1, 3, and 6/early termination (ET), the adherence rates remained ≥ 95.1% for the background antipsychotic in both pimavanserin and placebo treatment groups and ≥ 96.8% for pimavanserin. In ADVANCE, high adherence rates (≥90.6%) with the background antipsychotic (for both treatment groups) and pimavanserin (≥95.0%) were observed at weeks 2, 8, 14, and 26/ET. Conclusion: Rigorous screening was performed to exclude patients not adherent to their background antipsychotic before enrollment and to pimavanserin during study visits by using regular blood sampling. Mandatory caregiver participation further supported adherence to study treatment and procedures. These efforts may have contributed to the high levels of adherence to both background antipsychotic and pimavanserin reported in ENHANCE and ADVANCE.

Population Pharmacokinetic Modeling and Stochastic Simulations to Support Pediatric Dose Selection of Pimavanserin.

Pimavanserin is a selective serotonin-modulating agent with inverse agonist/antagonist activity at the 5-hydroxytryptamine2A (5-HT2A ) receptor. The safety and efficacy of pimavanserin 34 mg once daily were studied in adults with hallucinations and delusions associated with Parkinson's disease psychosis and other neuropsychiatric conditions. This analysis used model-based simulations of pimavanserin steady-state exposures to identify a dose that generated pediatric exposures comparable with adult exposures achieved with 34 mg pimavanserin. A population pharmacokinetics model was developed using pooled plasma drug concentration (ie, actual) data from 13 clinical studies, including a phase 1 study of adolescent pediatric patients (aged 13-17 years) with various psychiatric conditions. Stochastic simulations were performed to predict exposures in a virtual (ie, simulated) group of pediatric patients (aged 5-17 years). Steady-state measures of the area under the plasma concentration-time curve (AUC) and maximum drug concentration (Cmax ) were simulated for relevant age and weight stratifications and compared with simulated exposures in adults (aged 18-49 years). The simulated mean AUC ranged from 47.41 to 54.73 ng d/mL and the mean Cmax ranged from 41.13 to 50.07 ng/mL in adults receiving pimavanserin 34 mg. The simulated mean (SD) Cmax of 56.54 (24.58) ng/mL with pimavanserin 34 mg in patients aged 10-17 years was similar to that in adults. Pimavanserin 20 mg yielded a mean (SD) Cmax of 45.30 (21.31) ng/mL in patients aged 5-9 years and 49.18 (22.91) ng/mL in the pediatric patient weight group of 14-25 kg, which are values close to the Cmax in adults treated with 34 mg. Pimavanserin 20 and 34 mg in pediatric patients aged 5-9 and 10-17 years, respectively, yielded exposures similar to daily pimavanserin 34 mg in adults aged 18-49 years.

Pimavanserin Exposure-Response Analyses in Patients With Schizophrenia: Results From the Phase 2 ADVANCE Study.

PURPOSE/BACKGROUND: Pimavanserin is a selective serotonin 5-HT 2A receptor inverse agonist/antagonist being investigated in patients with negative symptoms of schizophrenia. This analysis aimed to characterize exposure-response relationships of pimavanserin in this population. METHODS/PROCEDURES: Exposure-response models were developed using data from ADVANCE. Patients with negative symptoms of schizophrenia receiving background antipsychotics were randomized to pimavanserin 20 mg (adjusted to 34 or 10 mg between weeks 2-8 based on efficacy or tolerability) or placebo for 26 weeks. Time-varying pimavanserin exposure measures were predicted for each patient using a population pharmacokinetic model and individual empiric Bayesian parameter estimates. Response measures were the Negative Symptom Assessment 16 (NSA-16, primary end point), Personal and Social Performance scale, negative symptoms component of the Clinical Global Impression of Schizophrenia-Severity Scale, and adverse events. FINDINGS/RESULTS: A higher pimavanserin exposure was associated with greater improvement in NSA-16 score. For a median area under the pimavanserin plasma concentration-time curve from time 0 to 24 hours of 1465 ng × h/mL for the 34-mg dose, the model predicted a 10.5-point reduction in NSA-16 score. This exposure-response relationship with NSA-16 scores was not influenced by covariates. Similar results were observed with Personal and Social Performance and Clinical Global Impression of Schizophrenia-Severity, but not to the extent as NSA-16. There was no significant exposure-response relationship with anxiety, headache, insomnia, or somnolence. IMPLICATIONS/CONCLUSIONS: Increasing pimavanserin plasma concentration was associated with improved NSA-16 scores (primary end point) in patients with negative symptoms of schizophrenia. No exposure-response relationship with select adverse events was observed.

Effects of adjunctive pimavanserin and current antipsychotic treatment on QT interval prolongation in patients with schizophrenia.

Background: Pimavanserin prolongs the QT interval, with mean increases in corrected QT (QTc) of 5-8 ms, and is currently being investigated for the treatment of negative symptoms of schizophrenia. Objectives: To assess QT interval prolongation in 3 studies investigating once-daily pimavanserin as an adjunct to current antipsychotic treatment in patients with schizophrenia. Methods: Electrocardiograms were unblinded from trials in which pimavanserin or placebo was added to main antipsychotics over 6 weeks (ENHANCE), 26 weeks (ADVANCE), and up to 78 weeks (ongoing 52-week, open-label extension study [study 035]) of treatment. Antipsychotic treatment was permitted throughout these studies. The 3 most frequently used antipsychotic treatments were examined-aripiprazole (including long-acting injectable), risperidone (including long-acting injectable), and olanzapine. QT intervals were corrected (QTc) using Fridericia's method, with elevated risk defined as either postbaseline value maximum of >500 ms or change from baseline to postbaseline maximum of >60 ms. Results: Of patients treated with adjunctive pimavanserin in ENHANCE, there were no postbaseline QTc values >481 ms; one patient in each of the risperidone and aripiprazole groups had change from baseline to postbaseline maximum >60 ms. More patients had change from baseline to postbaseline maximum ranging from 31 to 60 ms in the risperidone plus adjunctive placebo group (n = 5; 6.6%) than those in the risperidone plus adjunctive pimavanserin group (n = 3, 4.1%). In the pimavanserin plus antipsychotic group of ADVANCE, one patient had postbaseline QTc value >481 ms, and one patient treated with aripiprazole had change from baseline to postbaseline maximum of >60 ms. In study 035, a change from double-blind baseline to overall postbaseline maximum >60 ms occurred in one patient treated with aripiprazole and pimavanserin and in one patient treated with risperidone and pimavanserin. Similar proportions of patients had changes from double-blind baseline to post double-blind baseline maximum between 31 and 60 ms across treatments. No adverse events associated with an increase in the QTc interval were reported. Conclusions: Adjunctive pimavanserin with background antipsychotic treatment showed no evidence of QTc prolongation >500 ms postbaseline, consistent with previously reports on QT prolongation with pimavanserin.

Pimavanserin for negative symptoms of schizophrenia: results from the ADVANCE phase 2 randomised, placebo-controlled trial in North America and Europe.

BACKGROUND: Negative symptoms of schizophrenia are associated with adverse clinical outcomes, but there are few effective treatments. We aimed to assess the effects of pimavanserin, a selective 5-HT2A inverse agonist and antagonist, on negative symptoms of schizophrenia. METHODS: The ADVANCE study was a phase 2, 26-week, randomised, double-blind, placebo-controlled study of pimavanserin in stable outpatients with schizophrenia aged 18-55 years with predominant negative symptoms. Patients were randomly assigned (1:1) across 83 sites (18 in North America and 65 in Europe) to receive pimavanserin or placebo daily, added to an ongoing antipsychotic medication, per a computer-generated schedule (stratification by geographical region). Eligible patients had a score of at least 20 on the sum of seven Positive and Negative Syndrome Scale (PANSS) Marder negative factor items (and scores of ≥4 on at least three or ≥5 on at least two of negative symptom items). The starting dosage of 20 mg of pimavanserin or placebo could be adjusted to 34 mg or 10 mg within the first 8 weeks of the study, after which dosage remained stable until the end of the study. Both pimavanserin and placebo were administered orally once daily as two individual tablets (pimavanserin tablets were either 10 mg or 17 mg). The primary endpoint was change in total score using the 16-item Negative Symptom Assessment (NSA-16) from baseline to week 26. Primary outcomes were analysed in patients who received at least one dose of the study drug and had NSA-16 assessments at baseline and at least once post-baseline (full analysis set). Safety outcomes were analysed in patients who had received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov, NCT02970305, and is complete. FINDINGS: Between Nov 4, 2016, and April 16, 2019, we randomly assigned 403 patients to pimavanserin (n=201; 131 [65%] male; 187 [93%] White) or placebo (n=202; 137 [68%] male, 186 (92%) White), of whom 400 were included in the efficacy analysis (199 in the pimavanserin group, 201 in the placebo group). Mean age was 37·7 years (SD 9·4) in the pimavanserin group and 36·7 (9·2) years in the placebo group. The change in total NSA-16 score from baseline to week 26 was significantly improved with pimavanserin (least squares mean -10·4 [SE 0·67]) versus placebo (least squares mean -8·5 [0·67]; p=0·043; effect size: 0·211). The number of patients with treatment-emergent adverse events (TEAEs) was similar between groups: 80 (40%) patients experienced TEAEs in the pimavanserin group and 71 (35%) in the placebo group. Most TEAEs were headache (6% [n=13] vs 5% [n=10]) and somnolence (5% [n=11] vs 5% [n=10]). One patient from the placebo group reported severe headache (0·5%), rhinorrhoea (0·5%), cough (0·5%), and influenza (0·5%). In the pimavanserin group, one patient reported severe toothache (0·5%), and two patients had worsening of schizophrenia (1%). Mean change in QTcF interval was higher with pimavanerin (4·5 ms [SD 18·0]) than with placebo (0·0 ms [16·0]). INTERPRETATION: Stable patients with predominant negative symptoms of schizophrenia showed a reduction in negative symptoms after treatment with pimavanserin. However, given the small effect size, further investigation with optimised dosing is warranted to determine the clinical significance of this effect. FUNDING: Acadia Pharmaceuticals.

Bitopertin in Negative Symptoms of Schizophrenia-Results From the Phase III FlashLyte and DayLyte Studies.

BACKGROUND: There is currently no standard of care for treatment of negative symptoms of schizophrenia, although some previous results with glutamatergic agonists have been promising. METHODS: Three (SunLyte [WN25308], DayLyte [WN25309], and FlashLyte [NN25310]) phase III, multicenter, randomized, 24-week, double-blind, parallel-group, placebo-controlled studies evaluated the efficacy and safety of adjunctive bitopertin in stable patients with persistent predominant negative symptoms of schizophrenia treated with antipsychotics. SunLyte met the prespecified criteria for lack of efficacy and was declared futile. Key inclusion criteria were age ≥18 years, DSM-IV-TR diagnosis of schizophrenia, score ≥40 on the sum of the 14 Positive and Negative Syndrome Scale negative symptoms and disorganized thought factors, unaltered antipsychotic treatment, and clinical stability. Following a 4-week prospective stabilization period, patients were randomly assigned 1:1:1 to bitopertin (5 mg and 10 mg [DayLyte] and 10 mg and 20 mg [FlashLyte]) or placebo once daily for 24 weeks. The primary efficacy end point was mean change from baseline in Positive and Negative Syndrome Scale negative symptom factor score at week 24. RESULTS: The intent-to-treat population in DayLyte and FlashLyte included 605 and 594 patients, respectively. At week 24, mean change from baseline showed improvement in all treatment arms but no statistically significant separation from placebo in Positive and Negative Syndrome Scale negative symptom factor score and all other end points. Bitopertin was well tolerated. CONCLUSIONS: These studies provide no evidence for superior efficacy of adjunctive bitopertin in any of the doses tested over placebo in patients with persistent predominant negative symptoms of schizophrenia.

Efficacy and safety of adjunctive bitopertin versus placebo in patients with suboptimally controlled symptoms of schizophrenia treated with antipsychotics: results from three phase 3, randomised, double-blind, parallel-group, placebo-controlled, multicentre studies in the SearchLyte clinical trial programme.

BACKGROUND: Many patients with schizophrenia require high doses of medication for their ongoing psychotic symptoms. Glutamate theories and findings from studies showing efficacy of sarcosine, an endogenous, non-selective glycine-reuptake inhibitor mediated by GlyT1, offer an alternative approach. We undertook the SearchLyte trial programme to examine the efficacy of bitopertin, a selective GlyT1-mediated glycine-reuptake inhibitor, as an adjunctive treatment to ongoing antipsychotic treatment. METHODS: SearchLyte consisted of three phase 3, randomised, double-blind, parallel-group, placebo-controlled, multicentre studies done in outpatient clinics in Asia, Europe, and North and South America (TwiLyte done at 109 sites, NightLyte at 84, and MoonLyte at 87). Participants were male and female outpatients, aged at least 18 years, meeting DSM-IV criteria for schizophrenia with suboptimally controlled positive symptoms despite treatment with antipsychotics. Inclusion criteria included a Positive and Negative Syndrome Scale (PANSS) total score of at least 70 and antipsychotic treatment stability for the past 12 weeks before randomisation. Key exclusion criteria included meeting criteria for symptomatic remission or previous treatment with a GlyT1 inhibitor or any other investigational drug. After a screening or 4-week prospective stabilisation period, we randomly assigned participants (1:1:1) to a 12-week, double-blind treatment of either placebo or one of two fixed doses of oral, once-daily bitopertin (10 or 20 mg in TwiLyte and NightLyte; 5 or 10 mg in MoonLyte) added to their current antipsychotic medicine. After completion of 12 weeks' treatment, the study design allowed for additional double-blind treatment for 40 weeks to assess maintenance of the effect, followed by a randomised 4-week washout period to assess withdrawal effects. Subsequently, all patients were offered the opportunity to receive bitopertin treatment in a 3-year follow-up. The primary efficacy endpoint was the mean change from baseline in the PANSS Positive Symptom Factor Score (PSFS) at week 12, analysed in the modified intention-to-treat population. The trials were registered at ClinicalTrials.gov (numbers NCT01235520 [TwiLyte], NCT01235585 [MoonLyte], and NCT01235559 [NightLyte]). FINDINGS: Between Nov 19, 2010, and Dec 12, 2014, we randomly assigned 1794 patients to treatment, of whom 1772 were treated and analysed. MoonLyte was discontinued in September, 2014, on the basis of results from futility analyses. Across studies and treatment arms, most patients completed 12 weeks of treatment (505 in TwiLyte, 517 in NightLyte, and 506 in MoonLyte). Only one study, NightLyte, met the primary endpoint where the PANSS PSFS significantly differed from placebo at week 12, and only in the 10-mg arm: mean difference in score -1·37, 95% CI -2·27 to -0·47; p=0·0028. Improvements from baseline for the bitopertin 20-mg arm in Nightlyte were not significant compared with placebo: -3·77, 95% CI -4·40 to -3·14; p=0·3142. Results from the other two studies also did not differ from placebo (TwiLyte 0·58, 95% CI -0·34 to 1·50, p=0·22 for 10 mg and 0·43, -0·49 to 1·36, p=0·36 for 20 mg; MoonLyte 0·06, 95% CI -0·79 to 0·92, p=0·88 for 5 mg and 0·44, -0·41 to 1·28, p=0·31 for 10 mg). Placebo responses varied across studies and might have contributed to the differences in efficacy between studies. Four deaths occurred during the 12-week treatment period, three in NightLyte (upper gastrointestinal haemorrhage, alcohol poisoning and related head injury, and a completed suicide) and one in MoonLyte (myocardial infarction in a patient with pre-existing risk factors). Only the death by suicide was deemed related to the study drug. The incidence of serious adverse events was low across treatment groups in all three studies; psychiatric disorders were the most frequently reported serious adverse events and the most frequent cause of adverse events leading to discontinuation. INTERPRETATION: Only one of six active treatment arms across the three studies offered an advantage of adjunctive bitopertin over placebo for the treatment of suboptimally controlled symptoms of schizophrenia. The small improvement associated with bitopertin together with the varying placebo response suggests that adjunctive bitopertin treatment might offer only modest benefit to suboptimal responders to antipsychotics, if any. FUNDING: F Hoffmann-La Roche.

Psychometric evaluation of the Work Readiness Questionnaire in schizophrenia.

OBJECTIVE/INTRODUCTION: Unemployment can negatively impact quality of life among patients with schizophrenia. Employment status depends on ability, opportunity, education, and cultural influences. A clinician-rated scale of work readiness, independent of current work status, can be a valuable assessment tool. A series of studies were conducted to create and validate a Work Readiness Questionnaire (WoRQ) for clinicians to assess patient ability to engage in socially useful activity, independent of work availability. METHODS: Content validity, test-retest and inter-rater reliability, and construct validity were evaluated in three separate studies. RESULTS: Content validity was supported. Cronbach's α was 0.91, in the excellent range. Clinicians endorsed WoRQ concepts, including treatment adherence, physical appearance, social competence, and symptom control. The final readiness decision showed good test-retest reliability and moderate inter-rater reliability. Work readiness was associated with higher function and lower levels of negative symptoms. Low positive and high negative predictive values confirmed the concept validity. DISCUSSION: The WoRQ has suitable psychometric properties for use in a clinical trial for patients with a broad range of symptom severity. The scale may be applicable to assess therapeutic interventions. It is not intended to assess eligibility for supported work interventions. CONCLUSIONS: The WoRQ is suitable for use in schizophrenia clinical trials to assess patient work functional potential.

Report on ISCTM Consensus Meeting on Clinical Assessment of Response to Treatment of Cognitive Impairment in Schizophrenia.

If treatments for cognitive impairment are to be utilized successfully, clinicians must be able to determine whether they are effective and which patients should receive them. In order to develop consensus on these issues, the International Society for CNS Clinical Trials and Methodology (ISCTM) held a meeting of experts on March 20, 2014, in Washington, DC. Consensus was reached on several important issues. Cognitive impairment and functional disability were viewed as equally important treatment targets. The group supported the notion that sufficient data are not available to exclude patients from available treatments on the basis of age, severity of cognitive impairment, severity of positive symptoms, or the potential to benefit functionally from treatment. The group reached consensus that cognitive remediation is likely to provide substantial benefits in combination with procognitive medications, although a substantial minority believed that medications can be administered without nonpharmacological therapy. There was little consensus on the best methods for assessing cognitive change in clinical practice. Some participants supported the view that performance-based measures are essential for measurement of cognitive change; others pointed to their cost and time requirements as evidence of impracticality. Interview-based measures of cognitive and functional change were viewed as more practical, but lacking validity without informant involvement or frequent contact from clinicians. The lack of consensus on assessment methods was viewed as attributable to differences in experience and education among key stakeholders and significant gaps in available empirical data. Research on the reliability, validity, sensitivity, and practicality of competing methods will facilitate consensus.

Defining therapeutic benefit for people with schizophrenia: focus on negative symptoms.

Schizophrenia is a complex, heterogeneous, multidimensional disorder within which negative symptoms are a significant and disabling feature. Whilst there is no established treatment for these symptoms, some pharmacological and psychosocial interventions have shown promise and this is an active area of research. Despite the effort to identify effective interventions, as yet there is no broadly accepted definition of therapeutic success. This article reviews concepts of clinical relevance and reports on a consensus conference whose goal was to apply these concepts to the treatment of negative symptoms. A number of key issues were identified and discussed including: assessment of specific negative symptom domains; defining response and remission for negative symptoms; assessment of functional outcomes; measurement of outcomes within clinical trials; and the assessment of duration/persistence of a response. The group reached a definition of therapeutic success using an achieved threshold of function that persisted over time. Recommendations were agreed upon with respect to: assessment of negative symptom domains of apathy-avolition and deficit of expression symptoms; thresholds for response and remission of negative symptoms based on level of symptomatology; assessing multiple domains of function including social occupation, activities of daily living, and socialization; the need for clinical trial data to include rate of change over time and converging sources of evidence; use of clinician, patient and caregiver perspectives to assess success; and the need for establishing criteria for the persistence of therapeutic benefit. A consensus statement and associated research criteria are offered as an initial step towards developing broad agreement regarding outcomes of negative symptoms treatment.

Reliability, validity and ability to detect change of the PANSS negative symptom factor score in outpatients with schizophrenia on select antipsychotics and with prominent negative or disorganized thought symptoms.

The PANSS is a valid instrument assessing schizophrenia symptom severity. Analyses have identified a five-factor solution. The negative symptom factor (NSFS) is robust, having been replicated in multiple analyses. The score has superior content validity versus the negative subscale. Aspects of validity in patients with predominant negative symptoms have yet to be established. The present data are from a Phase IIb study of add-on bitopertin therapy in schizophrenia outpatients with prominent negative or disorganized thought symptoms treated with antipsychotics. Analyses were conducted to evaluate reliability, validity and sensitivity to change. Test-retest screening to baseline was high (ICC=0.93). This was maintained in-study, for patients with no change in CGI negative symptom severity (CGI-S-N). Internal consistency at baseline was adequate (α=0.71) and increased at later assessments. Pearson correlation at baseline showed a good association between NSFS and CGI-S-N (0.63), but not overall CGI-S (0.31). Association with PSP at baseline was moderate (-0.39) and for change at Week eight good (-0.65). NSFS responders (≥20% improvement) at Week eight showed a significant improvement in function. The analyses demonstrated reliability, validity and ability to detect change of the NSFS, in schizophrenia patients with prominent negative or disorganized thought symptoms.

Association of prominent positive and prominent negative symptoms and functional health, well-being, healthcare-related quality of life and family burden: a CATIE analysis.

BACKGROUND: There is an increased interest in evaluating the impact of core symptoms of schizophrenia, both positive and negative, on functioning and burden of disease. OBJECTIVE: To examine the extent to which prominent positive and prominent negative symptoms impact functional health, well-being, health-related quality of life (HRQoL), and family burden. METHODS: Data on symptomatology, HRQoL, and resource use from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) were analyzed (n=1447). Patients were divided into four groups based on the Positive and Negative Syndrome Scale (PANSS) using published criteria as having (a) neither prominent positive nor prominent negative symptoms (n=575; 39.7%); (b) only prominent negative symptoms (n=274; 18.9%); (c) only prominent positive symptoms (n=295; 20.4%); or (d) both prominent positive and negative symptoms (n=303; 20.9%). Differences were examined for overall significance between the groups and for a linear trend. RESULTS: There was a significant linear decline in the outcome measures with each subsequent symptom group, with the combination of prominent positive and negative symptoms incrementing the decline further on quality-adjusted life-years derived from the PANSS, Short-Form-12, Index of Functioning, HRQoL measures, and number of workdays missed by caregiver during the month prior to CATIE (all p<0.001). CONCLUSIONS: Both prominent positive and prominent negative symptoms of schizophrenia are independently associated with significant decline in functionality, HRQoL, and caregiver lost workdays. An increased burden is observed in patients with highest symptomatology. Further research is needed to determine predictors of poor outcomes and burden of schizophrenia.

Negative symptoms have greater impact on functioning than positive symptoms in schizophrenia: analysis of CATIE data.

Increased attention has been given to treatment of negative symptoms and its potential impact on functional outcomes, however previous inferences have been confounded by the fact that measures of functional outcomes often use items similar to those of negative symptoms. We attempted to discern the relative effects of negative symptoms on functioning, as compared to other symptoms, using data from the National Institute of Mental Health CATIE trial of chronic schizophrenia (n=1447) by examining correlations of Positive and Negative Syndrome Scale factors, Calgary Depression Rating Scale and select items from Heinrich's and Lehman's Quality of Life Scales measuring aspects of functioning that did not overlap with negative symptoms. Baseline functioning and change in functioning were more strongly related to PANSS negative factor than any of the other symptoms - though the amount of variance explained by symptom changes in general was small. The data suggests that improvement in negative symptoms may have a distinctive and independent effect on functional outcome relative to other symptoms. This should be further tested in studies where negative symptoms improve without concomitant improvement of other symptoms.

Effects of D-cycloserine on negative symptoms in schizophrenia.

INTRODUCTION: The negative and cognitive symptoms of schizophrenia are poorly responsive to neuroleptic treatment. Glutamatergic dysfunction may mediate some of these symptoms. Low dose D-cycloserine (DCS) is a partial agonist at the glycine site of the NMDA-associated receptor complex, noncompetitively enhancing NMDA neurotransmission. Prior studies suggest a beneficial effect of DCS on negative symptoms and cognition. This treatment trial was initiated to confirm and extend these findings. METHODS: Twenty-two male schizophrenic subjects displaying prominent negative symptoms who were stabilized on typical neuroleptics completed the study. A randomized double-blind parallel group design was used to compare the effects of 50 mg p.o. QD of DCS to placebo over 4 weeks. The two subject groups did not differ significantly in age, age of onset of illness or time on current neuroleptic treatment. Symptoms were rated by means of the SANS, BPRS and Abrams and Taylor rating scale. Cognition was assessed with the Sternberg Memory Test and the Continuous Performance Test. RESULTS: Both medication groups improved over the 4 weeks of treatment. However, there were no significant differences between the DCS and placebo group on any symptom rating. DCS effects on cognition did not differ from placebo. DISCUSSION: This study did not detect improvement in negative symptoms or cognitive performance with DCS treatment that has been found in some prior studies. This negative finding may be attributed to small sample size, relatively short duration of treatment and the overall modest effect of DCS. Future studies of DCS should be adequately powered to detect a small to medium effect size and should provide for a longer treatment phase than was used in this study in order to avoid a type II error.

Prepulse inhibition of acoustic startle in subjects with schizophrenia treated with olanzapine or haloperidol.

Studies of the acoustic startle response and of its inhibition by the presentation of a non-startling preliminary stimulus (prepulse inhibition, PPI) have revealed deficits in PPI in schizophrenic subjects compared to healthy controls. Animal studies indicate that atypical antipsychotics improve PPI deficits induced by NMDA antagonists more consistently than typical antipsychotics. The effect of medication status on PPI in schizophrenia is unresolved in the literature. In the current study the effects on PPI of the atypical antipsychotic olanzapine and the typical antipsychotic haloperidol were compared to the unmedicated state in subjects with schizophrenia. In a between-group design, 11 schizophrenic subjects on olanzapine, 16 subjects on haloperidol, and 14 subjects who were on no medication received acoustic startle testing with PPI determination. ANOVAs revealed no significant differences in startle to pulse alone stimuli, habituation of startle, or PPI between the olanzapine, haloperidol and unmedicated groups. These 41 subjects with schizophrenia were compared to a group of 21 historical healthy controls and found to have reduced PPI. These data do not indicate a preferential effect of olanzapine compared to haloperidol on sensorimotor gating in schizophrenia. The results are consistent with the hypothesis that PPI impairments are relatively stable across treatment conditions.