MMN responsivity to manipulations of frequency and duration deviants in chronic, clozapine-treated schizophrenia patients

Event-related potential (ERP) probing of abnormal sensory processes in schizophrenia with the mismatch negativity (MMN) has shown impairments in auditory change detection, but knowledge of the acoustic features leading to this deficit is incomplete. Changes in the duration and frequency properties of sound stimuli result in diminished MMNs in schizophrenia but it is unclear as to whether this reduced responsiveness is seen with more subtle changes in sound frequency. In a sample of 19 healthy controls and 21 patients with chronic schizophrenia treated with clozapine, MMN was assessed in response to tone frequency changes of 5%, 10% and 20%, and to tone duration changes. Patients exhibited reduced amplitudes and shorter latencies than controls to all frequency changes, and attenuated amplitudes to tone duration increments and decrements. Clozapine dose was related to MMN, with increasing dose being positively associated with frequency-MMN amplitudes (10% ∆f, 20% ∆f) and negatively associated with the amplitude and latency of duration-MMNs. These data support the well-established findings of auditory sensory abnormality in schizophrenia and underscore the sensitivity of MMN to relatively small auditory change detection deficits that may appear to characterize chronic schizophrenia.

A comparison of ziprasidone and risperidone in the long-term treatment of schizophrenia: a 44-week, double-blind, continuation study

OBJECTIVE

This randomized, double-blind, multicentre extension study compared the efficacy, tolerability, and safety of ziprasidone and risperidone for schizophrenia or schizoaffective disorder.

METHODS

Patients who had responded to treatment for an acute exacerbation of illness in an 8-week study received ziprasidone, 80 to 160 mg/day (n = 62), or risperidone, 6 to 10 mg/day (n = 77), for up to 44 additional weeks. Primary efficacy variables included changes in Positive and Negative Syndrome Scale (PANSS) total score and Clinical Global Impression Severity (CGI-S) score. Tolerability and safety assessments included movement disorders, adverse events, study discontinuation rates, and weight and metabolic parameters.

RESULTS

Both the ziprasidone and risperidone groups showed statistical improvement from baseline in PANSS and CGI-S scores at study end point with no significant differences between treatment groups. More risperidone-treated patients completed the study (41.6%) than ziprasidone-treated patients (33.9%), but the difference was not statistically significant. Ziprasidone-treated patients who completed the study showed greater improvement in depressive symptoms assessed by Montgomery and Asberg Depression Rating Scale than risperidone-treated patients (P < 0.05). Ziprasidone was associated with a more favourable effect on extrapyramidal symptom (EPS) measures and prolactin as well as less weight gain than risperidone. Median dosages were ziprasidone 120 mg/day and risperidone 8 mg/day.

CONCLUSIONS

Ziprasidone and risperidone demonstrated similar efficacy during long-term treatment of patients with schizophrenia or schizoaffective disorder. While more subjects on risperidone completed the extension study, ziprasidone was associated with fewer adverse effects on weight, EPS measures, and prolactin than risperidone.

Reduction of the immune response to factor VIII mediated through tolerogenic factor VIII presentation by immature dendritic cells

BACKGROUND

The development of neutralizing antibodies to factor FVIII (FVIII) represents the most serious complication in the treatment of hemophilia A.

OBJECTIVE

We have explored the potential of using immature dendritic cells (iDCs) to present FVIII in a tolerogenic manner to T cells.

METHODS

The iDCs were isolated from hemophilic murine bone marrow and pulsed with canine cFVIII (cFVIII-iDCs) in the presence or absence of the NFkappaB pathway blocking compound Andrographolide (Andro-cFVIII-iDCs). Three weekly intravenous infusions of one million cFVIII pulsed-iDCs were administered to a group of five hemophilic Balb/c mice. Anti-FVIII antibody levels were monitored by functional Bethesda assay after four weekly intravenous challenges with 2 IU of cFVIII.

RESULTS

We have shown that cFVIII in the presence or absence of Andro is efficiently taken up by iDCs and that this process does not result in the maturation of DCs or the activation of co-cultured T cells. Following repeated infusion of the cFVIII-iDCs and Andro-cFVIII-iDCs into hemophilic mice, which were subsequently challenged with cFVIII, long-term reductions of FVIII inhibitors of 25% and 40%, respectively, were documented. Studies of cytokine release and T-cell phenotypes indicate that the mechanisms responsible for reducing immunologic responsiveness to cFVIII appear to involve an expansion of Foxp3 T regulatory cells in the case of cFVIII-iDC infusion and the elaboration of the immunosuppressive cytokines IL-10 and TGF-beta following andrographolide-treated cFVIII-iDCs.

CONCLUSIONS

This study shows that tolerogenic presentation of cFVIII to the immune system can significantly reduce immunogenicity of the protein.

Monthly administration of long-acting injectable risperidone and striatal dopamine D2 receptor occupancy for the management of schizophrenia

OBJECTIVE

Long-acting risperidone administered intramuscularly biweekly is approved for the management of schizophrenia. However, dosing of long-acting antipsychotics is frequently extended in clinical practice, and a recent clinical trial has lent support to monthly dosing of long-acting risperidone. The objective of this positron emission tomography (PET) study was to examine the striatal dopamine D(2) binding of long-acting risperidone administered intramuscularly once a month.

METHOD

Following at least 3 maintenance monthly injections of 50 mg long-acting risper-idone, 7 patients with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder under-went PET using [(11)C]raclopride to measure D(2) binding potential within 4 days of the next scheduled injection. Data were collected from May to October 2003. This PET study was part of a larger 52-week clinical study wherein individuals received long-acting risperidone once monthly over a 1-year interval. One-year follow-up data were obtained from the 52-week parent investigation.

RESULTS

The mean +/- SD D(2) receptor occupancy was 56% +/- 24% (range, 29%-82%). Of note, there were 4 subjects with less than 60% D(2) occupancy, none of whom relapsed over the course of the 1-year follow-up. The mean +/- SD total plasma level of risperidone plus 9-hydroxyrisperidone was 16.6 +/- 12.3 ng/mL (range, 5.7-40.8).

CONCLUSION

As with plasma levels, there was considerable variability in D(2) occupancy levels for individuals receiving long-acting risperidone. This work suggests a possibility that sustained D(2) occupancy at or above the accepted threshold with acute clinical response may not be necessary to maintain response, a hypothesis with important clinical implications as we consider antipsychotic dosing and future antipsychotic development.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00236353.

Auditory hallucinations and the mismatch negativity: processing speech and non-speech sounds in schizophrenia

BACKGROUND

In line with emerging research strategies focusing on specific symptoms rather than global syndromes in psychiatric disorders, we examined the functional neural correlates of auditory verbal hallucinations (AHs) in schizophrenia. Recent neuroimaging and behavioural evidence suggest a reciprocal relationship between auditory cortex response to external sounds versus that induced by AHs.

METHODS

The mismatch negativity (MMN), a well established event-related potential (ERP) index of auditory cortex function, was assessed in 12 hallucinating patients (HP), 12 non-hallucinating patients (NP) and 12 healthy controls (HC). The primary endpoints, MMN amplitudes and latencies recorded from anterior and posterior scalp regions, were measured in response to non-phonetic and phonetic sounds.

RESULTS

While schizophrenia patients as a whole differed from HCs, no significant between-group differences were observed when patients were divided into hallucinated and non-hallucinated subgroups but, compared to NPs and HCs, whose MMN amplitudes were greatest in response to across phoneme change at frontal but not temporal sites, MMN amplitudes in HPs at frontal sites were not significantly different to any of the presented stimuli, while temporal MMNs in HPs were maximally sensitive to phonetic change.

SIGNIFICANCE

These findings demonstrate that auditory verbal hallucinations are associated with impaired pre-attentive processing of speech in fronto-temporal networks, which may involve defective attribution of significance that is sensitive to resource limitations. Overall, this research suggests that MMN may be a useful non-invasive tool for probing relationships between hallucinatory and neural states within schizophrenia and the manner in which auditory processing is altered in these afflicted patients.

Dissociating medication effects from learning and practice effects in a neurocognitive study of schizophrenia: Olanzapine versus haloperidol

OBJECTIVE

To contrast the effect of a typical antipsychotic (haloperidol) and an atypical antipsychotic (olanzapine) on neurocognitive functioning in schizophrenia when learning and practice (LP) effects are controlled.

METHODS

Two groups of participants were recruited, 27 schizophrenia patients in their first 5 years of illness and 13 normal controls. Prior to double-blind randomisation, all subjects were assessed on four occasions within 5 days (prerandomisation period) on the same neurocognitive battery. Repeated assessment prior to randomisation was chosen as a method to control for LP effects. Patients were then randomised to 56 days of treatment with haloperidol or olanzapine (postrandomisation). All subjects were assessed on neurocognitive measures at Days 28 and 56.

RESULTS

LP effects were present during the prerandomisation period on motor tasks, verbal and visual short-term memory, attention, and on a measure of verbal working memory. There were no changes in performance for patients randomised to treatment with olanzapine or haloperidol or the normal control group during the postrandomisation period.

CONCLUSIONS

Once LP effects are controlled, olanzapine and haloperidol do not affect performance on measures of motor functioning, verbal short-term memory, attention, verbal working memory, reaction time, visuospatial short-term memory, and visual working memory beyond that observed from LP effects.

Induction of partial immune tolerance to factor VIII through prior mucosal exposure to the factor VIII C2 domain

BACKGROUND

The development of anti-factor VIII (FVIII) neutralizing antibodies (inhibitors) is a significant obstacle to FVIII replacement therapy.

OBJECTIVE

As mucosal administration of an antigen may induce immune tolerance we have evaluated the efficacy of mucosal antigen exposure to achieve tolerance to FVIII.

METHODS

We investigated the effects of oral and nasal administration of the purified FVIII C2 domain (FVIII-C2) to FVIII-deficient BALB/c mice prior to FVIII protein challenge. Mice received oral or nasal doses of FVIII-C2, followed by a subcutaneous challenge of either FVIII-C2 or FVIII. The development of anti-FVIII inhibitors, cytokine production by splenocytes in vitro, and adoptive transfer assays were analyzed.

RESULTS AND CONCLUSIONS

Mucosal administration of FVIII-C2 decreases the titer of anti-FVIII-C2 inhibitors after FVIII-C2 challenge, and decreases the percentage of FVIII-C2 specific antibodies after challenge with full-length FVIII. Tolerance induction to FVIII-C2 is associated with increased IL-10 production by splenocytes in vitro, and can be adoptively transferred to naïve mice. This study is the first to demonstrate that tolerance to the FVIII-C2 domain can be induced via the mucosal route. Based on these results, the potential use of FVIII-specific mucosal tolerance induction as an immunotherapy treatment for anti-FVIII inhibitor development warrants further investigation.

Association study of the trinucleotide repeat polymorphism within SMARCA2 and schizophrenia

BACKGROUND

Brahma (BRM) is a key component of the multisubunit SWI/SNF complex, a complex which uses the energy of ATP hydrolysis to remodel chromatin. BRM contains an N-terminal polyglutamine domain, encoded by a polymorphic trinucleotide (CAA/CAG) repeat, the only known polymorphism in the coding region of the gene (SMARCA2). We have examined the association of this polymorphism with schizophrenia in a family-based and case/control study. SMARCA2 was chosen as a candidate gene because of its specific role in developmental pathways, its high expression level in the brain and some evidence of its association with schizophrenia spectrum disorder from genome-wide linkage analysis.

RESULTS

Family-based analysis with 281 complete and incomplete triads showed that there is no significant preferential transmission of any of the alleles to the affected offspring. Also, in the case/control analysis, similar allele and genotype distributions were observed between affected cases (n = 289) and unaffected controls (n = 273) in each of three Caucasian populations studied: French Canadian, Tunisian and other Caucasians of European origin.

CONCLUSION

Results from our family-based and case-control association study suggest that there is no association between the trinucleotide repeat polymorphism within SMARCA2 and schizophrenia.

A PET study evaluating dopamine D2 receptor occupancy for long-acting injectable risperidone

OBJECTIVE

Long-acting injectable risperidone represents the first clinically available depot atypical antipsychotic. The present study used positron emission tomography (PET) to evaluate its dopamine D(2) binding profile at doses of 25, 50, or 75 mg administered every 2 weeks.

METHOD

After achieving stabilization with one of the doses, nine patients with a diagnosis of schizophrenia or schizoaffective disorder underwent [(11)C]raclopride PET to measure D(2) occupancy. Participants were scanned twice during the 2-week injection interval: within 3 days after injection (postinjection) and within 5 days before the next injection (preinjection). At the same time, plasma was collected for measurements of risperidone plus 9-hydroxyrisperidone.

RESULTS

Mean post- and preinjection D(2) occupancy levels for the 25-, 50-, and 75-mg doses were 71.0% and 54.0%, 74.4% and 65.4%, and 81.5% and 75.0%, respectively. There was a significant correlation between dose and plasma concentrations of risperidone plus 9-hydroxyrisperidone, and the estimated plasma concentration associated with 50% D(2) occupancy (ED(50)) was 11.06 ng/ml. Prolactin levels were not correlated with drug levels or D(2) occupancy.

CONCLUSIONS

All three doses of injectable risperidone showed peak D(2) occupancy levels above the 65% threshold associated with optimal clinical response; the 75-mg dose approximated the 80% threshold linked to increased risk of extrapyramidal symptoms. Doses of 25 or 50 mg should provide therapeutic efficacy while minimizing the risk of extrapyramidal symptoms.

Increased prevalence of schizophrenia spectrum disorders in relatives of neuroleptic-nonresponsive schizophrenic patients

OBJECTIVE

It is suggested that schizophrenic patients who respond to neuroleptic medication and those who do not might differ with respect to their pathogenesis. In particular, it has been proposed that genetic factors may contribute to treatment response and/or outcome. In order to test this hypothesis, we compared the pattern of familial aggregation of schizophrenia related disorders in schizophrenic patients who are either responders (R) or nonresponders (NR) to typical neuroleptics.

METHOD

R (n=36) or NR (n=35) patients to typical neuroleptics and healthy controls (n=63) were recruited. At least one key informant relative of each proband was interviewed blind as to the status of the proband using the Family Interview for Genetic Studies. Morbid risk for schizophrenia and cluster A personality disorders and family loading score for schizophrenia were examined in first- and second-degree relatives of these probands.

RESULTS

First-degree relatives of NR patients were at a significantly higher risk for schizophrenia (MR=8.84), compared, respectively, to relatives of controls (MR=1.52) or relatives of R patients (MR=2.45). The same pattern was observed in second-degree relatives. Family loading score for schizophrenia in first- and second-degree relatives was significantly higher in NR compared to R patients.

CONCLUSIONS

Schizophrenic patients who do not respond to typical neuroleptics may suffer from a more familial form of schizophrenia compared to patients who are responders.

Expert Canadian consensus suggestions on the rational, clinical use of ziprasidone in the treatment of schizophrenia and related psychotic disorders

Many atypical antipsychotic medications are becoming available for clinical use. Ziprasidone is a recent addition to this group and is expected to become available for clinical use in Canada in 2005. Ziprasidone has some significant differences compared with other atypicals currently available in Canada. Clinicians need to understand the benefits and risks associated with each of the antipsychotic medications available for the treatment of schizophrenia and related psychotic disorders to ensure their most appropriate utilization. At the suggestion of Professor Stan Kutcher (chair) and as part of an ongoing commitment to provide independent education pertaining to the utility of new psychotropic compounds to health professionals, a panel of Canadian experts in the treatment of schizophrenia spectrum disorders was convened to provide consensus suggestions for the appropriate clinical use of ziprasidone. The consultations regarding the development of these recommendations were organized by Brainworks International (BWI) with arms-length funding from Pfizer Canada. This paper describes the experts' consensus views on the efficacy and safety of ziprasidone, their suggestions on which patients may be suitable for ziprasidone treatment, and how to initiate treatment (including how to switch from other antipsychotic medications), manage side effects, and monitor patients in long-term therapy. These suggestions are those of the authors only and are not endorsed by or necessarily reflect the opinions of BWI or Pfizer Canada.

CAA insertion polymorphism in the 3'UTR of Nogo gene on 2p14 is not associated with schizophrenia

The Nogo gene was putatively implicated in schizophrenia based on gene expression and genetic association data. In this study, we attempt to replicate the possible association of the CAA insertion and a nearby TATC deletion with schizophrenia in 204 complete and incomplete triads and in a sample of 462 unrelated cases and 153 controls, all of Caucasian origin. Our genotyping results indicated that neither the trinucleotide insertion polymorphism (CAAins; 43.4% vs. 41.8%, p>0.5) nor the polymorphism-TATC deletion (TATCdel; 49.8% vs. 49.3%, p>0.1) allele frequency is significantly different in patients compared to controls. The homozygous CAAins frequency is not significantly different between patients and controls either (18.0% vs. 15.0%, chi2=0.985, p>0.1). Furthermore, neither CAAins/TATCdel individually, nor the haplotype carrying both CAAins and TATCdel is preferentially transmitted to affected offspring.

Dopamine beta-hydroxylase (DBH) gene and schizophrenia phenotypic variability: a genetic association study

Recently, two polymorphisms (DBH5'-Ins/del and DBH 444 g/a) of the Dopamine Beta Hydroxylase (DBH) gene were isolated, and one haplotype (Del-a) was found to be associated with low DBH activity and cocaine-induced paranoia. The purpose of this study is to test for association between these two polymorphisms and schizophrenia or its phenotypic variability with respect to neuroleptic therapeutic response and symptom profile. Allelic and haplotype distributions of these two polymorphisms were compared between two groups of schizophrenic patients (excellent neuroleptic-responders; R, n = 42 and non-responders; NR, n = 64), and one group of healthy volunteers (n = 120). The "Del" and "a" alleles were in positive linkage disequilibrium. No allelic or genotype differences in the distribution of these two polymorphisms were observed between patients and controls. However, The Del-a haplotype was significantly more common in NR patients, and the mean total BPRS score was significantly higher in the group of patients with the Del-a compared to those without the Del-a haplotype. These results suggest that the DBH gene is not a causative factor in schizophrenia but that it may be a modulator of psychotic symptoms, severity of the disorder and therapeutic response to neuroleptic drugs.

Switching outpatients with schizophrenia and related disorders on long-acting injectable antipsychotics to olanzapine: an open-label naturalistic pilot study

Little is known about the feasibility of switching patients with schizophrenia from long-acting injectable antipsychotics to oral olanzapine. We completed an open-label 14-week study to assess such a transition. This study included 25 stable outpatients (DSM-IV diagnosis of schizophrenia, schizophreniform disorder, or schizoaffective disorder) who were receiving long-acting injectable antipsychotics. Following a screening visit, patients began treatment with olanzapine 10 mg/day, which was initiated the day of their scheduled injection. Clinical assessments included the Clinical Global Impression-Improvement Scale (CGI-I) and the Positive and Negative Syndrome Scale (PANSS). Patient self-reports of adverse events were monitored and the Extrapyramidal Symptoms Rating Scale completed at each visit. In those completing the trial (N = 18), results revealed that a switch from injectable antipsychotics to olanzapine was associated with significant improvements on the CGI-I, negative symptoms, PANSS total scores, and parkinsonism. In considering the whole sample (last observation carried forward, N = 25), significant improvements on the CGI-I, parkinsonism, and dyskinesia were observed. Finally, those who failed to complete the trial (N = 7) did not change significantly from visit 1 to endpoint on any of the efficacy or safety measures. These results should be considered preliminary and require replication using appropriate control groups.

Double-blind, placebo-controlled comparison of the efficacy of sertraline as treatment for a major depressive episode in patients with remitted schizophrenia

The effectiveness of selective serotonin reuptake inhibitors for depression in remitted schizophrenia has not been clearly demonstrated. A randomized, double-blind, prospective placebo-controlled study was performed of 48 subjects meeting DSM-IV criteria for both schizophrenia in remission and for a major depressive episode. Twenty-seven patients were randomized to placebo and 21 to sertraline. All subjects had a 1-week anticholinergic phase before randomization. The treatment duration was 6 weeks. Sertraline was started at 50 mg/day; this could be increased to 100 mg after 4 weeks for an inadequate response. There were no statistically significant differences in symptoms between the two groups at randomization. There were no differences in outcome between treatment groups. In both groups, between 40% and 50% of subjects showed a 50% reduction in depression score. This study does not provide support for the efficacy of sertraline in the treatment of depression in remitted schizophrenia. The small sample size limits the strength of the conclusions that can be drawn from this study. The study design called for a sample size of 96 on the basis of an expected placebo response rate of 30%. Recruitment for the study was difficult because of the placebo design. The placebo response was 50%. Clinicians and patients underestimate the strength of the placebo response and may overestimate the risk of participating in such a study. Testing the efficacy of widely accepted but poorly evaluated treatments should be a research priority. Future studies require a larger sample size and longer duration of treatment.

Neuropsychological impairments in neuroleptic-responder vs. -nonresponder schizophrenic patients and healthy volunteers

To determine whether two groups of schizophrenic patients representing the two extremes of the neuroleptic response-spectrum (consistent responders vs. consistent nonresponders) differ with respect to their neuropsychological profile. Neuroleptic-responder (R; n=36) and -nonresponder (NR; n=39) schizophrenic patients were recruited according to a priori defined criteria of responsiveness to typical neuroleptics. Seven neuropsychological domains were assessed and compared between groups: attention-vigilance, abstraction-flexibility, spatial organization, visual-motor processing, visual memory, verbal abilities, and verbal memory and learning. All measures were standardized using the scores of 36 healthy volunteers. NR schizophrenic patients performed worse in all neuropsychological domains compared to normal controls and R schizophrenic patients. However, only performances on visual memory, verbal abilities, and verbal memory and learning were significantly poorer in NR compared to R patients. Only the latter domain significantly differentiated NR patients from the other two groups. R patients performed at an intermediate level in all domains. This report of differences in neuropsychological profile between neuroleptic-responder and -nonresponder schizophrenic patients adds to the growing evidence supporting the value of distinguishing schizophrenic patients on the basis of their therapeutic response to neuroleptics.

Risperidone treatment of outpatients with schizophrenia: no evidence of sex differences in treatment response

OBJECTIVE

Given the renewed interest in the role of sex differences in schizophrenia, we undertook a post hoc analysis to determine whether sex differences in treatment response were present among outpatients with schizophrenia who received risperidone in an 8-week, open-label, Phase IV clinical study.

METHOD

We evaluated 330 adult patients (232 men, 98 women) with a DSM-III-R diagnosis of schizophrenia for safety and 292 (206 men, 86 women) for efficacy. Antipsychotic and antiparkinsonian medications were discontinued at study entry. Treatment with risperidone was initiated at a dosage of 2 mg daily, increased to the target dosage of 6 mg daily by day 3, and maintained at 6 mg daily until day 14. The dosage was then maintained at 6 mg daily, increased or decreased by 2 mg daily each week, based on the patient's response. Risperidone treatment was given for 8 weeks; the permitted dosage range was 4 mg to 10 mg daily.

RESULTS

Both male and female participants responded well to risperidone treatment; by the final assessment day, they had experienced decreases from baseline in their total Positive and Negative Syndrome Scale (PANSS) scores of 41.0% and 36.5%, respectively. Most male (77%) and female (78%) participants were considered to be PANSS responders: risperidone was effective against both the positive and negative symptoms of schizophrenia. Both sexes showed improvements over baseline in the incidence and severity of parkinsonism, dystonia, and dyskinesia. No significant (P > 0.05) sex differences in treatment response were observed for any of the efficacy outcomes or in the incidence and severity of extrapyramidal symptoms (EPS).

CONCLUSIONS

In this population of outpatients with chronic schizophrenia, both men and women responded well to flexible doses of risperidone. No significant sex differences were evident either in treatment response or in neurological side effects. The absence of sex differences in response to risperidone treatment may obviate the need for a sex-based differential dosing in schizophrenia management.