Augmentation strategies of clozapine with antipsychotics in the treatment of ultraresistant schizophrenia

Resting-state functional MRI in treatment-resistant schizophrenia

BACKGROUND

Abnormalities in brain regions involved in the pathophysiology of schizophrenia (SCZ) may present insight into individual clinical symptoms. Specifically, functional connectivity irregularities may provide potential biomarkers for treatment response or treatment resistance, as such changes can occur before any structural changes are visible. We reviewed resting-state functional magnetic resonance imaging (rs-fMRI) findings from the last decade to provide an overview of the current knowledge on brain functional connectivity abnormalities and their associations to symptoms in treatment-resistant schizophrenia (TRS) and ultra-treatment-resistant schizophrenia (UTRS) and to look for support for the dysconnection hypothesis.

METHODS

PubMed database was searched for articles published in the last 10 years applying rs-fMRI in TRS patients, i.e., who had not responded to at least two adequate treatment trials with different antipsychotic drugs.

RESULTS

Eighteen articles were selected for this review involving 648 participants (TRS and control cohorts). The studies showed frontal hypoconnectivity before the initiation of treatment with CLZ or riluzole, an increase in frontal connectivity after riluzole treatment, fronto-temporal hypoconnectivity that may be specific for non-responders, widespread abnormal connectivity during mixed treatments, and ECT-induced effects on the limbic system.

CONCLUSION

Probably due to the heterogeneity in the patient cohorts concerning antipsychotic treatment and other clinical variables (e.g., treatment response, lifetime antipsychotic drug exposure, duration of illness, treatment adherence), widespread abnormalities in connectivity were noted. However, irregularities in frontal brain regions, especially in the prefrontal cortex, were noted which are consistent with previous SCZ literature and the dysconnectivity hypothesis. There were major limitations, as most studies did not differentiate between TRS and UTRS (i.e., CLZ-resistant schizophrenia) and investigated heterogeneous cohorts treated with mixed treatments (with or without CLZ). This is critical as in different subtypes of the disorder an interplay between dopaminergic and glutamatergic pathways involving frontal, striatal, and hippocampal brain regions in separate ways is likely. Better definitions of TRS and UTRS are necessary in future longitudinal studies to correctly differentiate brain regions underlying the pathophysiology of SCZ, which could serve as potential functional biomarkers for treatment resistance.

Machine Learning Algorithm-Based Prediction Model for the Augmented Use of Clozapine with Electroconvulsive Therapy in Patients with Schizophrenia

The augmentation of clozapine with electroconvulsive therapy (ECT) has been an optimal treatment option for patients with treatment- or clozapine-resistant schizophrenia. Using data from the Research on Asian Psychotropic Prescription Patterns for Antipsychotics survey, which was the largest international psychiatry research collaboration in Asia, our study aimed to develop a machine learning algorithm-based substantial prediction model for the augmented use of clozapine with ECT in patients with schizophrenia in terms of precision medicine. A random forest model and least absolute shrinkage and selection operator (LASSO) model were used to develop a substantial prediction model for the augmented use of clozapine with ECT. Among the 3744 Asian patients with schizophrenia, those treated with a combination of clozapine and ECT were characterized by significantly greater proportions of females and inpatients, a longer duration of illness, and a greater prevalence of negative symptoms and social or occupational dysfunction than those not treated. In the random forest model, the area under the curve (AUC), which was the most preferred indicator of the prediction model, was 0.774. The overall accuracy was 0.817 (95% confidence interval, 0.793−0.839). Inpatient status was the most important variable in the substantial prediction model, followed by BMI, age, social or occupational dysfunction, persistent symptoms, illness duration > 20 years, and others. Furthermore, the AUC and overall accuracy of the LASSO model were 0.831 and 0.644 (95% CI, 0.615−0.672), respectively. Despite the subtle differences in both AUC and overall accuracy of the random forest model and LASSO model, the important variables were commonly shared by the two models. Using the machine learning algorithm, our findings allow the development of a substantial prediction model for the augmented use of clozapine with ECT in Asian patients with schizophrenia. This substantial prediction model can support further studies to develop a substantial prediction model for the augmented use of clozapine with ECT in patients with schizophrenia in a strict epidemiological context.

Place of the partial dopamine receptor agonist aripiprazole in the management of schizophrenia in adults: a Delphi consensus study

BACKGROUND

Aripiprazole is a second-generation antipsychotic, efficacious in patients with schizophrenia during acute episodes. Due to its pharmacological profile, aripiprazole may be of interest in patients with specific clinical profiles who have not been studied extensively in randomised clinical trials.

OBJECTIVES

To capture experience with aripiprazole in everyday psychiatric practice using the Delphi method in order to inform decision-making on the use of aripiprazole for the treatment of patients with schizophrenia in clinical situations where robust evidence from clinical trials is lacking.

METHODS

The scope of the survey was defined as the management of schizophrenia in adults. A systematic literature review was performed to identify the different clinical situations in which aripiprazole has been studied, and to describe the level of clinical evidence. Clinical profiles to include in the Delphi survey were selected if there was a clear interest in terms of medical need but uncertainty over the efficacy of aripiprazole. For each clinical profile retained, five to seven specific statements were generated and included in a questionnaire. The final 41-item questionnaire was proposed to a panel of 406 French psychiatrists with experience in the treatment of schizophrenia. Panellists rated their level of agreement using a Likert scale. A second round of voting on eleven items was organised to clarify points for which a consensus was not obtained in the first round.

RESULTS

Five clinical profiles were identified in the literature review (persistent negative symptoms, pregnancy, cognitive dysfunction, addictive comorbidity and clozapine resistance). Sixty-two psychiatrists participated in the first round of the Delphi survey and 33 in the second round. A consensus was obtained for 11 out of 41 items in the first round and for 9/11 items in the second round. According to the panellists' clinical experience, aripiprazole can be used as maintenance treatment for pregnant women, is relevant to preserve cognitive function and can be considered an option in patients with a comorbid addictive disorder or with persistent negative symptoms.

CONCLUSION

These findings may help physicians in choosing relevant ways to use aripiprazole and highlight areas where more research is needed to widen the evidence base.

Third-generation antipsychotics in patients with schizophrenia and non-responsivity or intolerance to clozapine regimen: What is the evidence?

Clozapine is considered « the golden standard » for the management of treatment-resistant schizophrenia, but many patients do not present adequate responsivity even to this antipsychotic. If we add the need to strictly monitor the hematologic and cardiometabolic adverse events during each clozapine trial and the difficulty of preserving therapeutic adherence in patients with low insight, residual negative/positive symptoms, or economic challenges, then the necessity of exploring alternative interventions for these patients becomes obvious. Also, in case of intolerance to clozapine or where clozapine did not induce remission, clinicians have to find new ways to help their patients. Switching to other antipsychotics or using these agents as add-ons to clozapine are the main interventions explored in this review, for patients with schizophrenia resistant to clozapine (ultra-resistant schizophrenia, URS). When clozapine intolerance is detected, conversion to another antipsychotic with distinct pharmacologic properties or formulation (e.g., long-acting intramuscular injectable agents, LAI) may be a useful option. Third-generation antipsychotics (TGA) have been selected for their distinct pharmacodynamically profile, which allows, at a theoretical level, their use in combination with clozapine. This narrative review is based on searching four electronic databases, that retrieved 19 primary and secondary reports on aripiprazole (seven case reports or case series presenting 24 patients; nine clinical trials, and three systematic reviews/meta-analyses), two primary reports on brexpiprazole (case report and case series, N = 3 patients), and six primary reports on cariprazine (case reports and case series, N = 14 patients). Based on the information collected from these reports, which included oral and LAI formulations, the TGA most supported by evidence for the augmentation of clozapine is aripiprazole (high-and medium-quality data), followed by cariprazine (low-quality data). Brexpiprazole has not yet been systematically explored for this indication, and in the case of lumateperone, no report could be found. The efficacy of aripiprazole and cariprazine was supported in the domains of positive, negative, and general symptoms, and aripiprazole may positively impact the metabolic profile in patients with URS. Also, adding TGA may lead to a decrease in the dose of clozapine concomitantly administered. More data derived from good quality research are needed in order to confirm the circumstances of TGAs recommendation in patients with URS, either as monotherapy, or added to clozapine.

Longitudinal course of cognition in schizophrenia: Does treatment resistance play a role?

Treatment-resistant schizophrenia (TRS) represents a main clinical issue, associated with worse functional outcome and higher healthcare costs. Clozapine is the most effective antipsychotic for TRS, although 40% of resistant patients, defined as ultra-treatment resistant (UTR), are clozapine-refractory. Previous literature suggests that TRS is characterized by worse cognitive functioning and a more disrupted neurobiological substrate, but only few studies focused on UTR schizophrenia. Moreover, despite this evidence and the central role of cognition, to date no study has investigated long-term cognitive outcome in TRS. Based on these premises, this study aims to analyze cross-sectional and long-term cognitive functioning of patients with schizophrenia, stratified according to antipsychotic response: first-line responders (FLRs), clozapine responders (CRs) and UTRs. We analyzed cross-sectional and retrospective cognitive evaluations of 93 patients with schizophrenia (32 FLRs, 42 CRs, 19 UTRs) over a mean follow-up period of 9 years, also taking into account possible influencing factors such as clinical severity and antipsychotic load. Analyses showed that UTR is associated with overall impaired cognitive functioning and represents the main predictor of long-term cognitive decline. We observed no significant differences between FLR and CR patients, which showed moderate cognitive improvement over time. This is the first study to report an association of treatment resistance with longitudinal cognitive course in schizophrenia, indicating that UTR is correlated with cognitive decline over time. This decline may either be a consequence of the persistence of psychotic symptoms or depend on a distinct and more disrupted neurobiological substrate affecting both cognition and antipsychotic response.

Clozapine resistant schizophrenia: Newer avenues of management

About 40%-70% of the patients with treatment-resistant schizophrenia have a poor response to adequate treatment with clozapine. The impact of clozapine-resistant schizophrenia (CRS) is even greater than that of treatment resistance in terms of severe and persistent symptoms, relapses and hospitalizations, poorer quality of life, and healthcare costs. Such serious consequences often compel clinicians to try different augmentation strategies to enhance the inadequate clozapine response in CRS. Unfortunately, a large body of evidence has shown that antipsychotics, antidepressants, mood stabilizers, electroconvulsive therapy, and cognitive-behavioural therapy are mostly ineffective in augmenting clozapine response. When beneficial effects of augmentation have been found, they are usually small and of doubtful clinical significance or based on low-quality evidence. Therefore, newer treatment approaches that go beyond the evidence are needed. The options proposed include developing a clinical consensus about the augmentation strategies that are most likely to be effective and using them sequentially in patients with CRS. Secondly, newer approaches such as augmentation with long-acting antipsychotic injections or multi-component psychosocial interventions could be considered. Lastly, perhaps the most effective way to deal with CRS would be to optimize clozapine treatment, which might prevent clozapine resistance from developing. Personalized dosing, adequate treatment durations, management of side effects and non-adherence, collaboration with patients and caregivers, and addressing clinician barriers to clozapine use are the principal ways of ensuring optimal clozapine treatment. At present, these three options could the best way to manage CRS until research provides more firm directions about the effective options for augmenting clozapine response.

Characteristics and definitions of ultra-treatment-resistant schizophrenia - A systematic review and meta-analysis

OBJECTIVE

The aim of this systematic review and meta-analysis was to characterize ultra-treatment-resistant Schizophrenia also known as clozapine-resistant schizophrenia (CRS) patients across clozapine combination and augmentation trials through demographic and clinical baseline data. Furthermore, we investigated the variability and consistency in CRS definitions between studies.

METHODS

Systematic searches of articles indexed in PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL) and PsycINFO were conducted in March 2020. 1541 randomized and non-randomized clinical trials investigating pharmacological and non-pharmacological clozapine add-on strategies were screened and a total of 71 studies were included. The primary outcome was the overall symptom score at baseline, measured with Positive and Negative Syndrome Scale (PANSS) total or Brief Psychiatric Rating Scale (BPRS) total scores.

RESULTS

Data from 2731 patients were extracted. Patients were overall moderately ill with a mean PANSS total score at baseline of 79.16 (±7.52), a mean duration of illness of 14.64 (±4.14) years with a mean clozapine dose of 436.94 (±87.47) mg/day. Illness severity data were relatively homogenous among patients independently of the augmentation strategy involved, although stark geographical differences were found. Overall, studies showed a large heterogeneity of CRS definitions and insufficient guidelines implementation.

CONCLUSIONS

This first meta-analysis characterizing CRS patients and comparing CRS definitions revealed a lack of consistent implementation of a CRS definition from guidelines into clinical trials, compromising the replicability of the results and their applicability in clinical practice. We offer a new score modeled on a best practice definition to help future trials increase their reliability.

Autistic traits and cognitive profiles of treatment-resistant schizophrenia

The complex pathophysiology of treatment-resistant schizophrenia (TRS) includes severe positive symptoms but also other symptom domains. The overlapping psychological profiles of schizophrenia and autistic spectrum disorder (ASD) are not established. We compared TRS patients (n = 30) with schizophrenia patients in remission (RemSZ, n = 28) and ASD patients (n = 28), focusing on both neurodevelopmental aspects and general and social cognitive impairments. The TRS group performed the worst on general neurocognition (measured by the MATRICS Consensus Cognitive Battery) and social cognition (measured by the theory of mind and emotional expression). The RemSZ group performed the best among the three groups. Regarding autistic traits, all measurements by the Autism-Spectrum Quotient/Autism Screening Questionnaire/Pervasive Developmental Disorder Assessment Rating Scale showed that (1) the ASD patients had the highest autistic traits (2) the TRS patients' scores were less severe than the ASD group's, but (3) the overall trends placed the TRS group between the ASD and the RemSZ group. These findings indicate that TRS patients and remitted patients could have distinctive neurodevelopmental and cognitive profiles. Further, the degrees of social cognitive dysfunction and autistic traits in TRS patients could be close to those of ASD patients, suggesting similarities between TRS and ASD.

Aberrant white matter microstructure in treatment-resistant schizophrenia✰

Treatment response in schizophrenia divides into three subcategories: treatment-responsive (first-line responders; FLR), treatment-resistant (TRS), and ultra-treatment-resistant schizophrenia (UTRS). White matter abnormalities could drive antipsychotic resistance but little work has investigated differences between TRS and UTRS. The current study aimed to establish whether differences in white matter structure are present across both treatment-resistant subtypes or if UTRS is distinct from TRS. Diffusion-weighted images were acquired for 18 individuals with TRS, 14 with UTRS, 18 FLR and 20 healthy controls. Measures of fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD) were obtained using tract-based spatial statistics. Analysis of variance and post-hoc t-tests were conducted for each measure. Those with TRS had lower FA than healthy controls in superior longitudinal fasciculus, corpus callosum, thalamic radiation, corticospinal tract, internal capsule, corona radiata and fronto-occipital fasciculus (p<.05 FWE-corrected). Lower FA was also observed in TRS compared with UTRS in the superior longitudinal fasciculus (p<.05 FWE-corrected). No post-hoc tests survived corrections for multiple comparisons and no differences in MD, AD or RD were observed. These data suggest that microstructural deficits in white matter could contribute to TRS but suggest that other mechanisms may be more relevant for UTRS.

Clozapine: An Updated Overview of Pharmacogenetic Biomarkers, Risks, and Safety-Particularities in the Context of COVID-19

BACKGROUND

clozapine (CLZ) use is precarious due to its neurological, cardiovascular, and hematological side effects; however, it is the gold standard in therapy-resistant schizophrenia (TRS) in adults and is underused.

OBJECTIVE

to examine the most recent CLZ data on (a) side effects concerning (b) recent pharmacological mechanisms, (c) therapy benefits, and (d) the particularities of the COVID-19 pandemic.

DATA SOURCES

a search was performed in two databases (PubMed and Web of Science) using the specific keywords "clozapine" and "schizophrenia", "side effects", "agranulocytosis", "TRS", or "bipolar affective disorder (BAF)" for the last ten years.

STUDY ELIGIBILITY CRITERIA

clinical trials on adults with acute symptoms of schizophrenia or related disorders.

RESULTS

we selected 37 studies, randomized controlled trials (RCTs), and clinical case series (CCS), centered on six main topics in the search area: (a) CLZ in schizophrenia, (b) CLZ in bipolar disorder, (c) side effects during the clozapine therapy, (d) CLZ in pregnancy, (e) CLZ in early-onset schizophrenia, and (f) CLZ therapy and COVID-19 infection.

LIMITATIONS

we considered RCTs and CCS from two databases, limited to the search topics. Conclusions and implications of key findings: (a) clozapine doses should be personalized for each patient based on pharmacogenetics testing when available; the genetic vulnerability postulates predictors of adverse reactions' severity; patients with a lower genetic risk could have less frequent hematological monitoring; (b) a CLZ-associated risk of pulmonary embolism imposes prophylactic measures for venous thromboembolism; (c) convulsive episodes are not an indication for stopping treatment; the plasma concentration of clozapine is a better side effect predictor than the dosage; (d) COVID-19 infection may enhance clozapine toxicity, generating an increased risk of pneumonia. Therapy must be continued with the proper monitoring of the white blood count, and the clozapine dose decreased by half until three days after the fever breaks; psychiatrists and healthcare providers must act together.

Implementation of pharmacogenetics in a clozapine treatment resistant patient: a case report

We report the case of a young Caucasian male with disorganized chronic schizophrenia, an active smoker and nonresponder to 400 mg of clozapine/day. Therapeutic clozapine monitoring was analyzed revealing a low clozapine:norclozapine ratio. An additional pharmacogenetic test was carried out showing that the patient carried *1F variant ( CYP1A2 gene), which has been associated with nonresponse to clozapine in smoker patients. A genetic variation in the SLC6A4 gene was also found, which could be related to the poor response to clozapine. The remainder of the genes analyzed ( CYP2D6, ABCB1 and HTR2A) were not directly associated with the patient’s phenotype. The dose of clozapine was increased to 600 mg/day, reaching the therapeutic range. This case shows how pharmacogenetics can help in understanding the value of plasma levels to provide clinical improvement.

Clozapine augmentation strategies - a systematic meta-review of available evidence. Treatment options for clozapine resistance

BACKGROUND

Treatment options for clozapine resistance are diverse whereas, in contrast, the evidence for augmentation or combination strategies is sparse.

AIMS

We aimed to extract levels of evidence from available data and extrapolate recommendations for clinical practice.

METHODS

We conducted a systematic literature search in the PubMed/MEDLINE database and in the Cochrane database. Included meta-analyses were assessed using Scottish Intercollegiate Guidelines Network criteria, with symptom improvement as the endpoint, in order to develop a recommendation grade for each clinical strategy identified.

RESULTS

Our search identified 21 meta-analyses of clozapine combination or augmentation strategies. No strategies met Grade A criteria. Strategies meeting Grade B included combinations with first- or second-generation antipsychotics, augmentation with electroconvulsive therapy for persistent positive symptoms, and combination with certain antidepressants (fluoxetine, duloxetine, citalopram) for persistent negative symptoms. Augmentation strategies with mood-stabilisers, anticonvulsants, glutamatergics, repetitive transcranial magnetic stimulation, transcranial direct current stimulation or cognitive behavioural therapy met Grades C-D criteria only.

CONCLUSION

More high-quality clinical trials are needed to evaluate the efficacy of add-on treatments for symptom improvement in patients with clozapine resistance. Applying definitions of clozapine resistance would improve the reporting of future clinical trials. Augmentation with second-generation antipsychotics and first-generation antipsychotics can be beneficial, but the supporting evidence is from low-quality studies. Electroconvulsive therapy may be effective for clozapine-resistant positive symptoms.

Clozapine and Psychosocial Function in Schizophrenia: A Systematic Review and Meta-Analysis

BACKGROUND

Clozapine has unique efficacy for symptoms in treatment-resistant schizophrenia; however, symptomatic remission is not necessary nor sufficient for functional improvement. No study has pooled the effect of clozapine on psychosocial function across clinical trials.

OBJECTIVE

We conducted a systematic review and meta-analysis to compare the effects of clozapine with other antipsychotics on psychosocial function, and described the predictors of functional outcome.

METHODS

We searched MEDLINE/PubMed, PsychINFO, EMBASE, CINAHL, Scopus, Web of Science, Cochrane Central Register of controlled trials and clinical trial registries till April 2018, with no language limits. Eligible studies were randomised controlled trials of clozapine vs. typical or atypical antipsychotics among adults with treatment-resistant schizophrenia. We included studies with flexible or fixed doses of antipsychotics within the therapeutic range to reflect naturalistic care. Effect sizes of studies were pooled using generic inverse variance and random-effects models and presented as standard mean differences. Study quality was assessed in accordance with the Cochrane Collaboration guideline, and subgroup analyses were carried out to identify potential moderators and methodological biases.

RESULTS

Nine studies with 1279 participants (69.7% male) were included. Clozapine showed beneficial effects on psychosocial function, but both short-term trials [n = 3; comparing 99 people taking clozapine with 97 controls (standardised mean difference = 0.04; 95% confidence interval - 0.24, 0.32; p = 0.77; I² = 0%)] and long-term trials [n = 5; comparing 415 people taking clozapine with 427 controls (standardised mean difference = 0.05; 95% confidence interval - 0.16, 0.27; p = 0.64; I² = 50%)] showed no superiority of clozapine to other antipsychotics in this regard. Only one study explored the predictors of psychosocial function. Baseline severity of illness, illicit drug use, extrapyramidal side effects, sex and cognition explained the variability in functional outcome. A range of scales measured psychosocial function, and the quality of reporting varied across trials.

CONCLUSIONS

Clozapine does not appear superior to other antipsychotics for improvement of psychosocial function. Standardisation of psychosocial function measurement is needed to improve the quality of evidence. Further exploration of the predictors of good psychosocial outcomes with clozapine treatment may improve personalisation of care.

Amisulpride augmentation in clozapine-unresponsive schizophrenia (AMICUS): a double-blind, placebo-controlled, randomised trial of clinical effectiveness and cost-effectiveness

BACKGROUND

When treatment-refractory schizophrenia shows an insufficient response to a trial of clozapine, clinicians commonly add a second antipsychotic, despite the lack of robust evidence to justify this practice.

OBJECTIVES

The main objectives of the study were to establish the clinical effectiveness and cost-effectiveness of augmentation of clozapine medication with a second antipsychotic, amisulpride, for the management of treatment-resistant schizophrenia.

DESIGN

The study was a multicentre, double-blind, individually randomised, placebo-controlled trial with follow-up at 12 weeks.

SETTINGS

The study was set in NHS multidisciplinary teams in adult psychiatry.

PARTICIPANTS

Eligible participants were people aged 18-65 years with treatment-resistant schizophrenia unresponsive, at a criterion level of persistent symptom severity and impaired social function, to an adequate trial of clozapine monotherapy.

INTERVENTIONS

Interventions comprised clozapine augmentation over 12 weeks with amisulpride or placebo. Participants received 400 mg of amisulpride or two matching placebo capsules for the first 4 weeks, after which there was a clinical option to titrate the dosage of amisulpride up to 800 mg or four matching placebo capsules for the remaining 8 weeks.

MAIN OUTCOME MEASURES

The primary outcome measure was the proportion of 'responders', using a criterion response threshold of a 20% reduction in total score on the Positive and Negative Syndrome Scale.

RESULTS

A total of 68 participants were randomised. Compared with the participants assigned to placebo, those receiving amisulpride had a greater chance of being a responder by the 12-week follow-up (odds ratio 1.17, 95% confidence interval 0.40 to 3.42) and a greater improvement in negative symptoms, although neither finding had been present at 6-week follow-up and neither was statistically significant. Amisulpride was associated with a greater side effect burden, including cardiac side effects. Economic analyses indicated that amisulpride augmentation has the potential to be cost-effective in the short term [net saving of between £329 and £2011; no difference in quality-adjusted life-years (QALYs)] and possibly in the longer term.

LIMITATIONS

The trial under-recruited and, therefore, the power of statistical analysis to detect significant differences between the active and placebo groups was limited. The economic analyses indicated high uncertainty because of the short duration and relatively small number of participants.

CONCLUSIONS

The risk-benefit of amisulpride augmentation of clozapine for schizophrenia that has shown an insufficient response to a trial of clozapine monotherapy is worthy of further investigation in larger studies. The size and extent of the side effect burden identified for the amisulpride-clozapine combination may partly reflect the comprehensive assessment of side effects in this study. The design of future trials of such a treatment strategy should take into account that a clinical response may be not be evident within the 4- to 6-week follow-up period usually considered adequate in studies of antipsychotic treatment of acute psychotic episodes. Economic evaluation indicated the need for larger, longer-term studies to address uncertainty about the extent of savings because of amisulpride and impact on QALYs. The extent and nature of the side effect burden identified for the amisulpride-clozapine combination has implications for the nature and frequency of safety and tolerability monitoring of clozapine augmentation with a second antipsychotic in both clinical and research settings.

TRIAL REGISTRATION

EudraCT number 2010-018963-40 and Current Controlled Trials ISRCTN68824876.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 49. See the NIHR Journals Library website for further project information.

Functional network dysconnectivity as a biomarker of treatment resistance in schizophrenia

Schizophrenia may develop from disruptions in functional connectivity regulated by neurotransmitters such as dopamine and acetylcholine. The modulatory effects of these neurotransmitters might explain how antipsychotics attenuate symptoms of schizophrenia and account for the variable response to antipsychotics observed in clinical practice. Based on the putative mechanisms of antipsychotics and evidence of disrupted connectivity in schizophrenia, we hypothesised that functional network connectivity, as assessed using network-based statistics, would exhibit differences between treatment response subtypes of schizophrenia and healthy controls. Resting-state functional MRI data were obtained from 17 healthy controls as well as individuals with schizophrenia who responded well to first-line atypical antipsychotics (first-line responders; FLR, n=18), had failed at least two trials of antipsychotics but responded to clozapine (treatment-resistant schizophrenia; TRS, n=18), or failed at least two trials of antipsychotics and a trial of clozapine (ultra-treatment-resistant schizophrenia; UTRS, n=16). Data were pre-processed using the Advanced Normalization Toolkit and BrainWavelet Toolbox. Network connectivity was assessed using the Network-Based Statistics toolbox in Matlab. ANOVA revealed a significant difference in functional connectivity between groups that extended between cerebellar and parietal regions to the frontal cortex (p<0.05). Post-hoc t-tests revealed weaker network connectivity in individuals with UTRS compared with healthy controls but no other differences between groups. Results demonstrated distinct differences in functional connectivity between individuals with UTRS and healthy controls. Future work must determine whether these changes occur prior to the onset of treatment and if they can be used to predict resistance to antipsychotics during first-episode psychosis.

Multidimensional Connectomics and Treatment-Resistant Schizophrenia: Linking Phenotypic Circuits to Targeted Therapeutics

Schizophrenia is a very complex syndrome that involves widespread brain multi-dysconnectivity. Neural circuits within specific brain regions and their links to corresponding regions are abnormal in the illness. Theoretical models of dysconnectivity and the investigation of connectomics and brain network organization have been examined in schizophrenia since the early nineteenth century. In more recent years, advancements have been achieved with the development of neuroimaging tools that have provided further clues to the structural and functional organization of the brain and global neural networks in the illness. Neural circuitry that extends across prefrontal, temporal and parietal areas of the cortex as well as limbic and other subcortical brain regions is disrupted in schizophrenia. As a result, many patients have a poor response to antipsychotic treatment and treatment failure is common. Treatment resistance that is specific to positive, negative, and cognitive domains of the illness may be related to distinct circuit phenotypes unique to treatment-refractory disease. Currently, there are no customized neural circuit-specific and targeted therapies that address this neural dysconnectivity. Investigation of targeted therapeutics that addresses particular areas of substantial regional dysconnectivity is an intriguing approach to precision medicine in schizophrenia. This review examines current findings of system and circuit-level brain dysconnectivity in treatment-resistant schizophrenia based on neuroimaging studies. Within a connectome context, on-off circuit connectivity synonymous with excitatory and inhibitory neuronal pathways is discussed. Mechanistic cellular, neurochemical and molecular studies are included with specific emphasis given to cell pathology and synaptic communication in glutamatergic and GABAergic systems. In this review we attempt to deconstruct how augmenting treatments may be applied within a circuit context to improve circuit integration and treatment response. Clinical studies that have used a variety of glutamate receptor and GABA interneuron modulators, nitric oxide-based therapies and a variety of other strategies as augmenting treatments with antipsychotic drugs are included. This review supports the idea that the methodical mapping of system-level networks to both on (excitatory) and off (inhibitory) cellular circuits specific to treatment-resistant disease may be a logical and productive approach in directing future research toward the advancement of targeted pharmacotherapeutics in schizophrenia.

Guidelines for the Pharmacotherapy of Schizophrenia in Adults

OBJECTIVE

The present guidelines address the pharmacotherapy of schizophrenia in adults across different stages, phases, and symptom domains.

METHOD

Guidelines were developed using the ADAPTE process, which takes advantage of existing guidelines. Six guidelines were identified for adaptation, with recommendations extracted from each. For those specific to the pharmacotherapy of schizophrenia in adults, a working group selected between guidelines and recommendations to create an adapted guideline.

RESULTS

Recommendations can be categorized into 6 areas that include 1) first-episode schizophrenia, 2) acute exacerbation, 3) relapse prevention and maintenance treatment, 4) treatment-resistant schizophrenia, 5) clozapine-resistant schizophrenia, and 6) specific symptom domains. For each category, recommendations are made based on the available evidence, which is discussed and linked to other established guidelines.

CONCLUSIONS

In most cases, evidence-based recommendations are made that can be used to guide current clinical treatment and decision making. Notably, however, there is a paucity of established evidence to guide treatment decision making in the case of clozapine-resistant schizophrenia, a subsample that represents a sizable proportion of those with schizophrenia.

Treatment-Resistant Schizophrenia

Although treatment-resistant schizophrenia (TRS) was described 50 years ago and has a gold standard treatment with clozapine based on well-defined criteria, there is still a matter of great interest and controversy. In terms of the underlying mechanisms of the development of TRS, progress has been made for the elucidation of the neurochemical mechanisms. Structural neuroimaging studies have shown that patients with TRS have significant reduction of the prefrontal cortex volume when compared with non- TRS. This article updates and enhances our previous review with new evidence mainly derived from new studies, clinical trials, systematic reviews, and meta-analyses.

Does cognitive impairment in treatment-resistant and ultra-treatment-resistant schizophrenia differ from that in treatment responders?

This study aimed to investigate whether cognitive impairment is more pronounced in people with treatment-resistant schizophrenia compared with those who respond well to first-line antipsychotic medication. Fifty-one patients with schizophrenia were assigned to one of three groups dependent on their clinical history: (i) 16 people who had responded well to first-line antipsychotic medication, (ii) 20 people who were treatment-resistant but responding to clozapine monotherapy, (iii) 15 people who were ultra-treatment-resistant/clozapine-resistant but responding to antipsychotic polypharmacy. Twenty-two controls were also recruited. Groups were matched for age, sex, disease duration and psychopathology. All participants undertook a computerised battery of neuropsychological tests that assessed multiple cognitive domains. Raw data were converted to z-scores, and test performance was compared between groups. People with schizophrenia performed significantly worse than controls in the majority of neuropsychological tests, with verbal memory, sustained attention, and sensorimotor the most commonly impaired domains. No significant differences in performance between people deemed to be treatment-resistant or ultra-treatment-resistant, and those who responded well to first-line antipsychotic medication were observed. There was no significant relationship between antipsychotic dose and scores on any of the neuropsychological tests. Cognitive impairment is a central feature of schizophrenia, but our results suggest that treatment-resistance may not be associated with more severe deficits.

Subtyping Schizophrenia by Treatment Response: Antipsychotic Development and the Central Role of Positive Symptoms

We have recently proposed a model for subtyping schizophrenia based on antipsychotic (AP) treatment response. Evidence suggests that APs, both old and new, are comparable in terms of efficacy; however, one AP, clozapine, is uniquely effective in one subgroup of patients (that is, those with treatment-resistant schizophrenia [TRS]). This permits us to subdivide schizophrenia into 3 specific groups: AP responsive, clozapine responsive, and clozapine resistant. Here, we integrate this model with current criteria related to TRS and ultraresistant schizophrenia, the latter referred to in our model as clozapine resistant. We suggest several modifications to existing criteria, in line with current evidence and practice patterns, particularly emphasizing the need to focus on positive symptoms. While APs can favourably impact numerous dimensions related to schizophrenia, it is their effect on positive symptoms that distinguishes them from other psychotropics. Further, it is positive symptoms that are central to AP and clozapine resistance, and it is these people that place the greatest demands on acute and long-term inpatient resources. In moving AP development forward, we advocate specifically focusing on positive symptoms and capitalizing on the evidence we have of 3 subtypes of psychosis (that is, positive symptoms) based on treatment response, implicating 3 distinguishable forms of underlying pathophysiology. Conversely, pooling these groups risks obfuscating potentially identifiable differences. Such a position does not challenge the importance of dopamine D2 receptor blockade, but rather highlights the need to better isolate those other subgroups that require something more or entirely different.

The poly(I:C)-induced maternal immune activation model in preclinical neuropsychiatric drug discovery

Increasing epidemiological and experimental evidence implicates gestational infections as one important factor involved in the pathogenesis of several neuropsychiatric disorders. Corresponding preclinical model systems based upon maternal immune activation (MIA) by treatment of the pregnant female have been developed. These MIA animal model systems have been successfully used in basic and translational research approaches, contributing to the investigation of the underlying pathophysiological mechanisms at the molecular, cellular and behavioral levels. The present article focuses on the application of a specific MIA rodent paradigm, based upon treatment of the gestating dam with the viral mimic polyinosinic-polycytidilic acid (Poly(I:C)), a synthetic analog of double-stranded RNA (dsRNA) which activates the Toll-like receptor 3 (TLR3) pathway. Important advantages and constraints of this animal model will be discussed, specifically in light of gestational infection as one vulnerability factor contributing to the complex etiology of mood and psychotic disorders, which are likely the result of intricate multi-level gene×environment interactions. Improving our currently incomplete understanding of the molecular pathomechanistic principles underlying these disorders is a prerequisite for the development of alternative therapeutic approaches which are critically needed in light of the important drawbacks and limitations of currently available pharmacological treatment options regarding efficacy and side effects. The particular relevance of the Poly(I:C) MIA model for the discovery of novel drug targets for symptomatic and preventive therapeutic strategies in mood and psychotic disorders is highlighted in this review article.

Extensive gray matter volume reduction in treatment-resistant schizophrenia

BACKGROUND

Approximately one-third of people with schizophrenia are treatment-resistant and some do not achieve remission with clozapine, the gold-standard antipsychotic medication for treatment-resistant schizophrenia. This study compared global and regional brain volumes between treatment-respondent and treatment-resistant patients with schizophrenia, including a group of patients who were clozapine-resistant.

METHODS

T1-weighted brain MRIs were obtained on a 3T scanner in 20 controls and 52 people with schizophrenia who were selected based on their symptomatic responses to antipsychotic medication: 18 responded well to first-line atypical antipsychotics (FLR), 19 were treatment-resistant but responsive to clozapine monotherapy (TR), and 15 were ultra-treatment-resistant and did not respond to clozapine (UTR). Treatment groups were matched for disease duration and current psychopathology. SIENAX and FSL-VBM were used to investigate differences in the global brain, gray matter (GM), white matter, ventricular cerebrospinal fluid volumes, and regional GM volumes.

RESULTS

GM volume was significantly reduced in the TR and UTR groups compared with controls and the FLR group (p < 0.05). GM volume was significantly reduced in TR patients compared with FLRs in the superior, middle, and inferior temporal gyri, pre- and post-central gyri, middle and superior frontal gyri, right supramarginal gyrus, and right lateral occipital cortex. UTR patients showed reduced GM compared with FLRs in their right parietal operculum and left cerebellum. No significant volume differences were observed between TR and UTR groups.

CONCLUSIONS

These differences are unlikely to be solely due to medication effects, and reduced GM volume in treatment-resistant schizophrenia may represent an accelerated disease course or a different underlying pathology.

Glutamatergic neurometabolites in clozapine-responsive and -resistant schizophrenia

BACKGROUND

According to the current schizophrenia treatment guidelines, 3 levels of responsiveness to antipsychotic medication exist: those who respond to first-line antipsychotics, those with treatment-resistant schizophrenia who respond to clozapine, and those with clozapine-resistant or ultra-treatment resistant schizophrenia. Proton magnetic resonance spectroscopy studies indicate that antipsychotic medication decreases glutamate or total glutamate + glutamine in the brains of patients with schizophrenia and may represent a biomarker of treatment response; however, the 3 levels of treatment responsiveness have not been evaluated.

METHODS

Proton magnetic resonance spectroscopy spectra were acquired at 3 Tesla from patients taking a second generation non-clozapine antipsychotic (first-line responders), patients with treatment-resistant schizophrenia taking clozapine, patients with ultra-treatment resistant schizophrenia taking a combination of antipsychotics, and healthy comparison subjects.

RESULTS

Group differences in cerebrospinal fluid-corrected total glutamate + glutamine levels scaled to creatine were detected in the dorsolateral prefrontal cortex [df(3,48); F = 3.07, P = .04, partial η(2) = 0.16] and the putamen [df(3,32); F = 2.93, P = .05, partial η(2) = 0.22]. The first-line responder group had higher dorsolateral prefrontal cortex total glutamate + glutamine levels scaled to creatine than those with ultra-treatment resistant schizophrenia [mean difference = 0.25, standard error = 0.09, P = .04, family-wise error-corrected]. Those with treatment-resistant schizophrenia had higher total glutamate + glutamine levels scaled to creatine in the putamen than the first-line responders (mean difference = 0.31, standard error = 0.12, P = .05, family-wise error-corrected) and those with ultra-treatment-resistant schizophrenia (mean difference = 0.39, standard error = 0.12, P = .02, family-wise error-corrected).

CONCLUSIONS

Total glutamate + glutamine levels scaled to creatine in the putamen may represent a marker of response to clozapine. Future studies should investigate glutamatergic anomalies prior to clozapine initiation and following successful treatment.

Augmentation strategies in partial responder and/or treatment-resistant schizophrenia patients treated with clozapine

INTRODUCTION

Although clozapine (CLZ) is considered the best evidence-based therapeutic option for treatment of resistant schizophrenia patients, a significant proportion of CLZ-treated patients show a partial or inadequate response to treatment, leading to increased healthcare cost and poor quality of life for affected individuals.

AREAS COVERED

This paper comprises a review of main research in CLZ augmentation strategies for treatment-refractory schizophrenia, with a focus on research conducted between 1990 and 2014. Databases that were searched include: PubMed, CINAHL, EMBASE PsychINFO, AgeLine and Cochrane Database of Systematic Reviews. Primary search terms were 'clozapine augmentation', 'clozapine and add-on' and 'treatment-resistant schizophrenia', with cross reference to specific agents covered in this article. We reviewed the available evidence on CLZ augmentation with antipsychotics, antidepressants, mood stabilizers and other agents.

EXPERT OPINION

Many drugs have been evaluated as CLZ add-on therapies without demonstrating convincing efficacy in treating refractory schizophrenia symptoms. More research is needed to better define outcomes in schizophrenia, the topic of treatment-resistance and more well-designed trials are required to establish true efficacy and safety of CLZ augmentation strategies.

Antipsychotic dosing: found in translation

In the field of schizophrenia research, as in other areas of psychiatry, there is a sense of frustration that greater advances have not been made over the years, calling into question existing research strategies. Arguably, many purported gains claimed by research have been "lost in translation," resulting in limited impact on diagnosis and treatment in the clinical setting. There are exceptions; for example, we would argue that different lines of preclinical and clinical research have substantially altered how we look at antipsychotic dosing. While this story remains a work in progress, advances "found in translation" have played an important role. Detailing these changes, the present paper speaks to a body of evidence that has already shifted clinical practice and raises questions that may further alter the manner in which antipsychotics have been administered over the last 6 decades.

Ziprasidone as Adjunctive Therapy in Severe Bipolar Patients Treated with Clozapine

Aim. To confirm the efficacy and tolerability of ziprasidone as adjunctive therapy in bipolar patients partially responding to clozapine or with persisting negative symptoms, overweight, or with metabolic syndrome. Methods. Eight patients with psychotic bipolar disorder were tested with the BPRS, the HAM-D, and the CGI at T0 and retested after 2 weeks (T1). Plasma clozapine and norclozapine levels and BMI were tested at T0 and T1. Results. Ziprasidone was well tolerated by all the patients. BPRS and HAM-D scores were reduced in all patients. BMI was reduced in patients with a BMI at T0 higher than 25. Plasma levels of clozapine and norclozapine showed an irregular course.

The neurobiology of relapse in schizophrenia

Dopamine's proposed role in psychosis proved a starting point in our understanding of the neurobiology of relapse, fitting given the central role positive symptoms play. This link is reflected in early work examining neurotransmitter metabolite and drug (e.g. amphetamine, methylphenidate) challenge studies as a means of better understanding relapse and predictors. Since, lines of investigation have expanded (e.g. electrophysiological, immunological, hormonal, stress), an important step forward if relapse per se is the question. Arguably, perturbations in dopamine represent the final common pathway in psychosis but it is evident that, like schizophrenia, relapse is heterogeneous and multidimensional. In understanding the neurobiology of relapse, greater gains are likely to be made if these distinctions are acknowledged; for example, efforts to identify trait markers might better be served by distinguishing primary (i.e. idiopathic) and secondary (e.g. substance abuse, medication nonadherence) forms of relapse. Similarly, it has been suggested that relapse is 'neurotoxic', yet individuals do very well on clozapine after multiple relapses and the designation of treatment resistance. An alternative explanation holds that schizophrenia is characterized by different trajectories, at least to some extent biologically and/or structurally distinguishable from the outset, with differential patterns of response and relapse. Just as with schizophrenia, it seems naïve to conceptualize the neurobiology of relapse as a singular process. We propose that it is shaped by the form of illness and in place from the outset, modified by constitutional factors like resilience, as well as treatment, and confounded by secondary forms of relapse.

Practitioner review: schizophrenia spectrum disorders and the at-risk mental state for psychosis in children and adolescents--evidence-based management approaches

BACKGROUND

Schizophrenia spectrum disorders are severe mental illnesses which often result in significant distress and disability. Attempts have been made to prospectively identify and treat young people viewed as at high risk of impending nonaffective psychosis. Once a schizophrenia spectrum disorder has developed, prompt identification and management is required.

METHODS

This article reviews the literature relating to the assessment and management of 'at-risk mental states' (ARMS) and the treatment of schizophrenia spectrum disorders in children and adolescents. A systematic search of the literature was undertaken using EMBASE, MEDLINE, PsycINFO databases for the period January 1970-December 2012.

RESULTS

Evidence suggests that young people fulfilling the ARMS criteria are at high risk of adverse mental health outcomes but that the majority do not develop nonaffective psychosis over the medium term. Although clinical trial findings have been inconsistent, psychosocial approaches, such as cognitive behaviour therapy, may reduce the risk of transition to psychosis and improve some symptoms, at least over the short term. The effectiveness of psychotropic medication for the ARMS is uncertain although there is accumulating evidence for potential adverse effects of antipsychotic medication, even at low dose, in this population. For the schizophrenias, clinical trial findings suggest that, as in adults, antipsychotics should be selected on the basis of side-effect profile although clozapine may be helpful in treatment refractory illness. There are almost no studies of psychosocial treatments for schizophrenia in young people under 18, and some caution must be exercised when extrapolating the findings of adult studies to younger individuals.

CONCLUSIONS

A stepped care approach to the ARMS in young people represents a plausible potential management approach for those at high risk of serious mental health problems. However, predictive models currently lack precision and should focus on accurately identifying those at high risk for a variety of poor outcomes who may benefit most from intervention. There is also an urgent need for age-specific research in the area of psychosocial treatments for children and adolescents with schizophrenia.

Aripiprazole versus haloperidol in combination with clozapine for treatment-resistant schizophrenia: a 12-month, randomized, naturalistic trial

BACKGROUND

Long-term studies for patients with resistant schizophrenia are necessary to assess the effectiveness of combination strategies on persisting positive symptoms.

AIMS AND METHODS

This multicenter, naturalistic, randomized, superiority study (ClinicalTrials.gov identifier: NCT00395915) aimed to compare clinical efficacy and tolerability of haloperidol versus aripiprazole as combination treatment with clozapine in patients with resistant schizophrenia.

RESULTS

One hundred six patients were followed up for 12 months. After 12 months, the proportion of patients who discontinued treatment was not significantly different between aripiprazole and haloperidol (37% vs 28%, respectively; P = 0.431). The change in the Brief Psychiatric Rating Scale score was similar in the aripiprazole and haloperidol groups (-7.0 vs -7.9, respectively; P = 0.389), whereas the tolerability total score decreased significantly more in the aripiprazole group (-7.2 vs -2.3; P = 0.008).

CONCLUSIONS

While the effectiveness of clozapine augmentation with a second antipsychotic agent is not clearly demonstrated yet, results from this study suggest that augmentation with aripiprazole offers no substantial benefit over haloperidol in efficacy. Aripiprazole was perceived more tolerable than haloperidol, but it is uncertain how this finding may translate into the real world of clinical practice.

Association of antipsychotic polypharmacy with health service cost: a register-based cost analysis

OBJECTIVE

To investigate the association of antipsychotic polypharmacy in schizophrenia with cost of primary and secondary health service use.

METHOD

Comparative analysis of health service cost for patients prescribed antipsychotic polypharmacy versus antipsychotic monotherapy. Resource utilisation and costs were described using central Danish registers for a 2 year period (2007-2008). We included patients attached to one of two Danish psychiatric referral centres in 1 January 2008 and/or 1 January 2009. Their prescribed treatment with either antipsychotic polypharmacy or monotherapy at the two cross-sectional dates was recorded and used as proxy of polypharmacy exposure during the preceding year. A multivariate generalised linear model was fitted with total costs of primary and secondary health service use as dependent variable, and antipsychotic polypharmacy, diagnosis, age, gender, disease duration, psychiatric inpatient admissions, and treatment site as covariates.

RESULTS

The sample consisted of 736 outpatients with a diagnosis in the schizophrenia spectrum. Antipsychotic polypharmacy was associated with significantly higher total health service costs compared with monotherapy (2007: 25% higher costs; 2008: 17% higher costs) when adjusting for potential confounders and risk factors. A subgroup analysis suggested that the excessive costs associated with antipsychotic polypharmacy were partly accounted for by the functional level of the patients.

CONCLUSION

The results demonstrate that antipsychotic co-prescribing is associated with increased use of health care services, even though no causal relations can be inferred from an observational study.

Schizophrenia as a disorder of too little dopamine: implications for symptoms and treatment

Antipsychotics represent the first effective therapy for schizophrenia, with their benefits linked to dopamine D2 blockade. Schizophrenia was soon identified as a hyperdopaminergic disorder, and antipsychotics proved to be reasonably effective in controlling positive symptoms. However, over the years, schizophrenia has been reconceptualized more broadly, now defined as a heterogeneous disorder with multiple symptom domains. Negative and cognitive features, not particularly responsive to antipsychotic therapy, have taken on increased importance--current thinking suggests that these domains predate the onset of positive symptoms and are more closely tied to functional outcome. That they are better understood in the context of decreased dopamine activity suggests that schizophrenia may fundamentally represent a hypodopaminergic disorder. This shift in thinking has important theoretical implications from the standpoint of etiology and pathophysiology, but also clinically in terms of treatment and drug development.

Addition of aripiprazole to the clozapine may be useful in reducing anxiety in treatment-resistant schizophrenia

There exist many case reports and studies on the antipsychotic augmentation by aripirazole in partial responders to clozapine, the most seem to be finding a slight difference in the PANSS and CGI scores after the aripirazole addition. The results of our report are compatible with those of other studies but, we have found a considerable antianxiety action in both of the cases. The 5HT1A agonism of aripirazole could be hypothesized as mechanism contributing to this effect.

Effects of antipsychotics on the behavioral deficits in human dominant-negative DISC1 transgenic mice with neonatal polyI:C treatment

Interactions of environmental and genetic factors may play a role in the pathoetiology of schizophrenia. We have recently developed a novel animal model of mental disorders such as schizophrenia by inducing abnormal immune response during the perinatal period in mice with overexpression of the human dominant-negative form of disrupted-in-schizophrenia 1 (DN-DISC1). In the present study, we investigated the effects of antipsychotics on the behavioral deficits in this animal model for mental disorders with gene-environment interaction. Neonatal DN-DISC1 transgenic (DN-DISC1 tg) mice were repeatedly injected with polyriboinosinic-polyribocytidylic acid (polyI:C) for 5 days from postnatal days 2 to 6. The behavioral analyses were performed in adulthood. Clozapine (3mg/kg) or haloperidol (1mg/kg) was administered orally once a day from 1 week before starting a series of behavioral experiments and continued until the end of the study. Cognitive impairment in polyI:C-treated DN-DISC1 tg mice was improved by repeated administration of clozapine while haloperidol had no effect. Both antipsychotics suppressed the augmentation of MK-801-induced hyperactivity in the model mice. Neither clozapine nor haloperidol ameliorated the impairments of social behaviors in polyI:C-treated DN-DISC1 tg mice. These results suggest that the polyI:C-treated DN-DISC tg mice are quite unique as an animal model for mental disorders. Furthermore, this mouse model may be useful for the screening of potential antipsychotic compounds that could be more effective than clozapine in ameliorating negative symptoms and cognitive impairment in schizophrenia.

Association of an UCP4 (SLC25A27) haplotype with ultra-resistant schizophrenia

AIMS

Neuronal uncoupling proteins are involved in the regulation of reactive oxygen species production and intracellular calcium homeostasis, and thus, play a neuroprotective role. In order to explore the potential consequences of neuronal uncoupling proteins variants we examined their association in a sample of Caucasian patients suffering from schizophrenia and phenotyped them according to antipsychotic response.

MATERIALS & METHODS

Using a case-control design, we compared the frequencies of 15 genetic variants spanning UCP2, UCP4 and UCP5 in 106 French Caucasian patients suffering from schizophrenia and 127 healthy controls. In addition, patients with schizophrenia who responded to antipsychotic treatment were compared with patients with ultra-resistant schizophrenia (URS). This latter population presented no clinical, social and/or occupational remission despite at least two periods of treatment with conventional or atypical antipsychotic drugs and also with clozapine.

RESULTS

There were no differences in the distribution of the respective alleles between URS and responding patients. However, one haplotype spanning UCP4 was found to be significantly under-represented in URS patients. This relationship remained significant after multiple testing corrections.

CONCLUSION

Although our sample is of limited size and not representative of schizophrenia as a whole, the association found between the URS group and the UCP4 haplotype is noteworthy as it may influence treatment outcome in schizophrenia.

Pharmacotherapy for treatment-resistant schizophrenia

Schizophrenia is a disabling mental illness with a lifetime prevalence of 0.7% worldwide and significant, often devastating, consequences on social and occupational functioning. A range of antipsychotic medications are available; however, suboptimal therapeutic response in terms of psychotic symptoms is common and affects up to one-third of people with schizophrenia. Negative symptoms are generally less amenable to treatment. Because of the consequences of inadequate symptom control, effective treatment strategies are required for people with treatment-resistant schizophrenia. Clozapine has been shown to be more effective than other antipsychotics in treatment-resistant populations in several studies; however, the occurrence of adverse effects, some of which are potentially life-threatening, are important limitations. In addition to those who are intolerant to clozapine, only 30% to 50% experience clinically significant symptom improvement. This review describes the recent evidence for treatment strategies for people not responding to nonclozapine antipsychotic agents and people not responding or only partially responding to clozapine.

Cognitive effects of antipsychotic dosage and polypharmacy: a study with the BACS in patients with schizophrenia and schizoaffective disorder

Antipsychotic polypharmacy and high doses have been associated with poorer outcome, longer hospital stays, and increased side effects. The present naturalistic study assessed the cognitive effects of antipsychotics in 56 patients with a diagnosis of schizophrenia or schizoaffective disorder, using the Brief Assessment of Cognition in Schizophrenia (BACS). Antipsychotic daily dose (ADD) was expressed as mg risperidone equivalents/day (RIS eq), using a model based on drug doses from the Clinical Antipsychotic Trials in Intervention Effectiveness (CATIE) study for second generation antipsychotics (SGA) and chlorpromazine equivalents for first generation antipsychotics (FGA), with a 1/1 equivalence between haloperidol and risperidone. Increasing age was associated with polypharmacy, FGA prescription and decreasing BACS score. FGA prescription, in turn, predicted a poorer cognitive functioning, independently of age, PANSS subscores and ADD. ADD was associated with decreasing cognitive scores, an effect that remained significant after controlling for age, PANSS or polypharmacy. The detrimental cognitive effects of polypharmacy, in turn, appeared to be mediated by ADD. Different methods of data fitting suggested that ADD above 5-6 mg RIS eq/day were associated with lower BACS scores. Overall, these results show that increasing antipsychotic daily dose is associated with poorer cognitive functioning at doses lower than previously thought, independently of the number of antipsychotic drugs.

Association of Disrupted in Schizophrenia 1 (DISC1) missense variants with ultra-resistant schizophrenia

Three common missense variants of the Disrupted in Schizophrenia 1 (DISC1) gene, rs3738401 (Q264R), rs6675281 (L607F) and rs821616 (S704C), have been variably associated with the risk of schizophrenia. In a case-control study, we examine whether these gene variants are associated with schizophrenia and ultra-resistant schizophrenia (URS) in a population of French Caucasian patients. The URS phenotype is characterized according to stringent criteria as patients who experience no clinical, social and/or occupational remission in spite of treatment with clozapine and at least two periods of treatment with distinct conventional or atypical antipsychotic drugs. We find a significant association between DISC1 missense variants and URS. The association with rs3738401 remains significant after appropriate correction for multiple testing. These results suggest that the DISC1 rs3738401 missense variant is statistically linked with ultra-resistance to antipsychotic treatment.

Progress in defining optimal treatment outcome in schizophrenia

Historically, schizophrenia has been associated with early-onset, persistent symptoms, and progressive decline accompanied by poor functional recovery. The advent of effective drugs in the 1950s improved symptom control, at least from the standpoint of positive features (e.g. hallucinations, delusions). However, even here the response was limited and efficacy in other symptom domains (cognitive, deficit/negative) was minimal. With clozapine as the prototype, the second-generation antipsychotics arrived in the 1990s with claims of improved tolerability, as well as greater and broader clinical efficacy, all of which was to translate to gains in functional outcome and quality of life. The capacity of these drugs to effect such changes has since been tempered, but it remains that the research and hope generated served as an impetus to redefine outcomes. A medical-based model, centred on pharmacotherapy and symptom resolution, has given way to a re-conceptualization of schizophrenia and treatment goals. There is a clearer distinction between clinical and functional outcomes, and, with this, greater attention has been given to these other symptom domains that curtail improvement in the latter. At the same time, a concerted shift to shared decision making has underscored quality-of-life issues that benefit from, but cannot be guaranteed by, either clinical or functional improvement. To this end, the field has now embraced a recovery model that is seen as a process, multidimensional and individualized, rather than dichotomous and symptom driven.