Topiramate augmentation of clozapine in schizophrenia: a double-blind, placebo-controlled study

Augmentation strategies for clozapine resistance: a systematic review and meta-analysis

BACKGROUND

Several augmentation strategies have been used to improve symptomatology in patients not adequately responding to clozapine. Several randomised controlled trials (RCTs) have evaluated the efficacy of different strategies to augment clozapine. This systematic review and meta-analysis reviewed the available RCTs that have evaluated the clinical efficacy of various pharmacological agents, non-pharmacological strategies (occupational therapy, cognitive behaviour therapy), and somatic treatment [electroconvulsive therapy (ECT), repetitive transcranial magnetic stimulation, etc.)] as augmenting agents to clozapine.

METHODS

Data were extracted using standard procedures, and risk of bias was evaluated. Effect sizes were computed for the individual studies.

RESULTS

Forty-five clinical trials were evaluated. The pooled effect size for various antipsychotic medications was 0.103 (95% CI: 0.288-0.493, p < 0.001); when the effect size was evaluated for specific antipsychotics for which more than one trial was available, the effect size for risperidone was -0.27 and that for aripiprazole was 0.57. The effect size for lamotrigine was 0.145, and that for topiramate was 0.392. The effect size for ECT was 0.743 (CI: 0.094-1.392). Risk of bias was low (mean Jadad score - 3.93). Largest effect sizes were seen for mirtazapine (effect size of 5.265). Most of the studies can be considered underpowered and limited by small sample sizes.

CONCLUSIONS

To conclude, based on the findings of the present systematic review and meta-analysis, it can be said that compared to other treatment strategies, clozapine non-responsive patients respond maximum to mirtazapine followed by ECT.

Pharmacological and nonpharmacological augmentation treatments for clozapine-resistant schizophrenia: A systematic review and network meta-analysis with normalized entropy assessment

OBJECTIVE

To integrate all evidence derived from randomized controlled trials (RCTs) of both pharmacological and nonpharmacological augmentation interventions for clozapine-resistant schizophrenia (CRS).

METHODS

Six major electronic databases were systematically searched for RCTs published until July 10, 2021. The primary outcome was change in overall symptoms, and the secondary outcomes were positive and negative symptoms and acceptability. We performed random-effects network meta-analysis. Normalized entropy was calculated to examine the uncertainty of treatment ranking.

RESULTS

We identified 35 RCTs (1472 patients with 23 active augmentation treatments) with a mean daily clozapine dose of 440.80 (91.27) mg for 1168.22 (710.28) days. Network meta-analysis of overall symptoms (reported as standardized mean difference; 95 % confidence interval) with consistent results indicated that mirtazapine (-4.41; -5.61, -3.21), electroconvulsive therapy (ECT) (-4.32; -5.43, -3.21), and memantine (-2.02; -3.14, -0.91) were ranked as the best three treatments. For positive symptoms, ECT (-5.18; -5.86, -4.49) was ranked the best with less uncertainty. For negative symptoms, memantine (-3.38; -4.50, -2.26), duloxetine (-3.27; -4.25, -2.29), and mirtazapine (-1.73; -2.71, -0.74) were ranked the best three treatments with less uncertainty. All antipsychotics, N-methyl d-aspartate receptor agonists, and antiepileptics were not associated with more efficacy than placebo. Compared to placebo, only amisulpride had statistically significant lower discontinuation rate (risk ratio: 0.21; 95 % CI: 0.05, 0.93).

CONCLUSION

Add-on mirtazapine, ECT, and memantine were the most efficacious augmentation options for CRS. Data on other important outcomes such as cognitive functioning or quality of life were rarely reported, making further large-scale, well-designed RCTs necessary. (PROSPERO number, CRD42021262197.).

Pharmacological interventions for prevention of weight gain in people with schizophrenia

BACKGROUND

Antipsychotic-induced weight gain is an extremely common problem in people with schizophrenia and is associated with increased morbidity and mortality. Adjunctive pharmacological interventions may be necessary to help manage antipsychotic-induced weight gain. This review splits and updates a previous Cochrane Review that focused on both pharmacological and behavioural approaches to this problem.

OBJECTIVES

To determine the effectiveness of pharmacological interventions for preventing antipsychotic-induced weight gain in people with schizophrenia.

SEARCH METHODS

The Cochrane Schizophrenia Information Specialist searched Cochrane Schizophrenia's Register of Trials on 10 February 2021. There are no language, date, document type, or publication status limitations for inclusion of records in the register.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) that examined any adjunctive pharmacological intervention for preventing weight gain in people with schizophrenia or schizophrenia-like illnesses who use antipsychotic medications.

DATA COLLECTION AND ANALYSIS

At least two review authors independently extracted data and assessed the quality of included studies. For continuous outcomes, we combined mean differences (MD) in endpoint and change data in the analysis. For dichotomous outcomes, we calculated risk ratios (RR). We assessed risk of bias for included studies and used GRADE to judge certainty of evidence and create summary of findings tables. The primary outcomes for this review were clinically important change in weight, clinically important change in body mass index (BMI), leaving the study early, compliance with treatment, and frequency of nausea. The included studies rarely reported these outcomes, so, post hoc, we added two new outcomes, average endpoint/change in weight and average endpoint/change in BMI.

MAIN RESULTS

Seventeen RCTs, with a total of 1388 participants, met the inclusion criteria for the review. Five studies investigated metformin, three topiramate, three H2 antagonists, three monoamine modulators, and one each investigated monoamine modulators plus betahistine, melatonin and samidorphan. The comparator in all studies was placebo or no treatment (i.e. standard care alone). We synthesised all studies in a quantitative meta-analysis. Most studies inadequately reported their methods of allocation concealment and blinding of participants and personnel. The resulting risk of bias and often small sample sizes limited the overall certainty of the evidence. Only one reboxetine study reported the primary outcome, number of participants with clinically important change in weight. Fewer people in the treatment condition experienced weight gains of more than 5% and more than 7% of their bodyweight than those in the placebo group (> 5% weight gain RR 0.27, 95% confidence interval (CI) 0.11 to 0.65; 1 study, 43 participants; > 7% weight gain RR 0.24, 95% CI 0.07 to 0.83; 1 study, 43 participants; very low-certainty evidence). No studies reported the primary outcomes, 'clinically important change in BMI', or 'compliance with treatment'. However, several studies reported 'average endpoint/change in body weight' or 'average endpoint/change in BMI'. Metformin may be effective in preventing weight gain (MD -4.03 kg, 95% CI -5.78 to -2.28; 4 studies, 131 participants; low-certainty evidence); and BMI increase (MD -1.63 kg/m2, 95% CI -2.96 to -0.29; 5 studies, 227 participants; low-certainty evidence). Other agents that may be slightly effective in preventing weight gain include H2 antagonists such as nizatidine, famotidine and ranitidine (MD -1.32 kg, 95% CI -2.09 to -0.56; 3 studies, 248 participants; low-certainty evidence) and monoamine modulators such as reboxetine and fluoxetine (weight: MD -1.89 kg, 95% CI -3.31 to -0.47; 3 studies, 103 participants; low-certainty evidence; BMI: MD -0.66 kg/m2, 95% CI -1.05 to -0.26; 3 studies, 103 participants; low-certainty evidence). Topiramate did not appear effective in preventing weight gain (MD -4.82 kg, 95% CI -9.99 to 0.35; 3 studies, 168 participants; very low-certainty evidence). For all agents, there was no difference between groups in terms of individuals leaving the study or reports of nausea. However, the results of these outcomes are uncertain given the very low-certainty evidence.

AUTHORS' CONCLUSIONS

There is low-certainty evidence to suggest that metformin may be effective in preventing weight gain. Interpretation of this result and those for other agents, is limited by the small number of studies, small sample size, and short study duration. In future, we need studies that are adequately powered and with longer treatment durations to further evaluate the efficacy and safety of interventions for managing weight gain.

Augmentation of Antipsychotic Medications with Low-Dose Clozapine in Treatment-Resistant Schizophrenia-Case Reports and Discussion

Treatment resistance in schizophrenia is often encountered in clinical practice, with clozapine usually recommended as the appropriate therapy. However, where clozapine proves ineffective or cannot be tolerated due to side effects, treatment options are limited. In patients within forensic mental health services, residual symptomatology often presents a barrier to discharge and can have lasting effects on prospects for rehabilitation as well as risk to self and others. This paper presents a review of the relevant literature and three cases of a novel approach, utilising clozapine in doses usually considered subtherapeutic, in combination with the primary antipsychotic treatment. In all three patients, it improved clinical efficacy as well as tolerability, resulting in improvement that allowed discharge from the forensic hospital.

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.

Outcomes and safety of concomitant topiramate or metformin for antipsychotics-induced obesity: a randomized-controlled trial

BACKGROUND

Although there are some existing data describing the usage of topiramate in patients with antipsychotic-induced obesity, study on its comparison with metformin is limited. This study aimed to explore the effectiveness and safety of concomitant topiramate on antipsychotic-induced obesity as well as its comparison with metformin.

METHODS

62 stabilized outpatients with antipsychotic-induced obesity were randomized into the topiramate group and the metformin group with 16-week treatment. The patients' weight, body mass index (BMI), waist-hip ratio, and their side effects were assessed and compared. Intention-to-treat and completer analyses were performed. Meanwhile, covariance analysis was conducted to control the impact of the significant difference in BMI between the two groups.

RESULTS

The two groups had comparable characteristics, though their difference in baseline BMI was significant. (1) Intention-to-treat analyses: the random missing values were replaced using the last observation carried forward method when intention-to-treat analyses were conducted. Compared with the baseline, the weight, BMI, and waist-hip ratio in the topiramate group markedly decreased at each follow-up, whereas, in the metformin group, only waist-hip ratio significantly decreased at 4 weeks after treatment. Compared with the metformin, only weight and BMI in the topiramate group were significantly decreased at week 4 after treatment, and at week 8-16, weight, BMI and waist-hip ratio were remarkably declined. (2) Completer analyses: compared with the baseline, the weight, BMI, and waist-hip ratio in the topiramate group at week 4-16 were markedly decreased, whereas only waist-hip ratio with metformin was significantly decreased at week 4. Compared with the metformin, all BMI with topiramate were markedly decreased at week 4-16. Moreover, its weight and waist-hip ratio also were notably lowered at week 8. No significant differences in adverse events were found between the two groups.

CONCLUSIONS

Topiramate, similar to metformin in reducing obesity as previously reported, also significantly reduced body weight, BMI, and waist-hip ratio in patients with antipsychotic-induced obesity and demonstrated well tolerance in psychiatric patients. Trial registration The trial was registered at http://www.chictr.org.cn , and the number was ChiCTR-IPR-17013122.

The clozapine to norclozapine ratio: a narrative review of the clinical utility to minimize metabolic risk and enhance clozapine efficacy

Introduction: Clozapine remains the most effective antipsychotic for treatment-refractory schizophrenia. However, ~40% of the patients respond insufficiently to clozapine. Clozapine's effects, both beneficial and adverse, have been proposed to be partially attributable to its main metabolite, N-desmethylclozapine (NDMC). However, the relation of the clozapine to norclozapine ratio (CLZ:NDMC; optimally defined as ~2) to clinical response and metabolic outcomes is not clear.Areas covered: This narrative review comprehensively examines the clinical utility of the CLZ:NDMC ratio to reduce metabolic risk and increase treatment efficacy. The association of the CLZ:NDMC ratio with changes in psychopathology, cognitive functioning, and cardiometabolic burden will be explored, as well as adjunctive treatments and their effects.Expert opinion: The literature suggests a positive association between the CLZ:NDMC ratio and better cardiometabolic outcomes. Conversely, the CLZ:NDMC ratio appears inversely associated with better cognitive functioning but less consistently with other psychiatric domains. The CLZ:NDMC ratio may be useful for predicting and monitoring cardiometabolic adverse effects and optimizing potential cognitive benefits of clozapine. Future studies are required to replicate these findings, which if substantiated, would encourage examination of adjunctive treatments aiming to alter the CLZ:NDMC ratio to best meet the needs of the individual patient, thereby broadening clozapine's clinical utility.

Topiramate mitigates weight gain in antipsychotic-treated patients with schizophrenia: meta-analysis of randomised controlled trials

OBJECTIVE

Weight gain is one of the most challenging issues in patients with schizophrenia treated with antipsychotics. Several meta-analyses have been conducted to review the efficacy of topiramate in reducing weight, however, several issues regarding the methodology had arisen of which make the results remain ambiguous.

METHODS

We conducted a meta-analysis of randomised controlled trials about the use of topiramate in patients with schizophrenia for weight reduction. Ten double-blinded randomised placebo-controlled trials and seven open-label randomised controlled trials included 905 patients.

RESULTS

Patients treated with topiramate experienced a greater reduction in body weight and BMI. Patients in countries of the lower overweight population showed more significant BMI reduction. Besides, studies from the Middle East and South Asia showed the greatest effect in body weight change, followed by East Asia, then Europe/America. Topiramate group was outperformed control group with significant psychopathology improvement. No difference between two groups regarding the overall side effects.

CONCLUSIONS

Topiramate was significantly superior to control group in mitigating weight gain and psychopathology in antipsychotic-treated patients with schizophrenia. The effects of topiramate augmentation need further investigations in larger definitive studies using methodological rigor and thorough assessments.

Resistance is not futile: treatment-refractory schizophrenia - overview, evaluation and treatment

INTRODUCTION

Schizophrenia is a debilitating condition with three main symptom domains: positive, negative, and cognitive. Approximately one-third of persons with schizophrenia will fail to respond to treatment. Growing evidence suggests that treatment-resistant (refractory) schizophrenia (TRS) may be a distinct condition from treatment-respondent schizophrenia. There is limited evidence on effective treatments for TRS, and a lack of standardized diagnostic criteria for TRS has hampered research. Areas covered: A literature search was conducted using Pubmed.gov and the EMBASE literature database. The authors discuss the pragmatic definitions of TRS and review treatments consisting of antipsychotic monotherapy and augmentation strategies. Expert opinion: Currently available first-line antipsychotic medications are generally effective at treating the positive symptoms of schizophrenia, leaving residual negative and cognitive symptoms. Before diagnosing TRS, rule out any pharmacodynamic or pharmacokinetic failures. Most evidence supports clozapine as having the most efficacy for TRS. If clozapine is used, it should be optimized, and serum levels should be at least 350-420 ng/ml. If clozapine is unable to be tolerated, some evidence suggests olanzapine at dosages up to 40mg/day can be useful. Augmentation strategies have weak evidence. Tailoring treatment to the specific domain is the preferred approach, and the use of a structured assessment/outcome measure is encouraged.

Augmentation strategies for clozapine refractory schizophrenia: A systematic review and meta-analysis

BACKGROUND

Although clozapine is the most effective medication for treatment refractory schizophrenia, only 40% of people will meet response criteria. We therefore undertook a systematic review and meta-analysis of global literature on clozapine augmentation strategies.

METHODS

We systematically reviewed PubMed, PsycInfo, Embase, Cochrane Database, Chinese Biomedical Literature Service System and China Knowledge Resource Integrated Database for randomised control trials of augmentation strategies for clozapine resistant schizophrenia. We undertook pairwise meta-analyses of within-class interventions and, where possible, frequentist mixed treatment comparisons to differentiate treatment effectiveness Results: We identified 46 studies of 25 interventions. On pairwise meta-analyses, the most effective augmentation agents for total psychosis symptoms were aripiprazole (standardised mean difference: 0.48; 95% confidence interval: -0.89 to -0.07) fluoxetine (standardised mean difference: 0.73; 95% confidence interval: -0.97 to -0.50) and, sodium valproate (standardised mean difference: 2.36 95% confidence interval: -3.96 to -0.75). Memantine was effective for negative symptoms (standardised mean difference: -0.56 95% confidence interval: -0.93 to -0.20). However, many of these results included poor-quality studies. Single studies of certain antipsychotics (penfluridol), antidepressants (paroxetine, duloxetine), lithium and Ginkgo biloba showed potential, while electroconvulsive therapy was highly promising. Mixed treatment comparisons were only possible for antipsychotics, and these gave similar results to the pairwise meta-analyses.

CONCLUSIONS

On the basis of the limited data available, the best evidence is for the use of aripiprazole, fluoxetine and sodium valproate as augmentation agents for total psychosis symptoms and memantine for negative symptoms. However, these conclusions are tempered by generally short follow-up periods and poor study quality.

Intrinsic and Antipsychotic Drug-Induced Metabolic Dysfunction in Schizophrenia

For decades, there have been observations demonstrating significant metabolic disturbances in people with schizophrenia including clinically relevant weight gain, hypertension, and disturbances in glucose and lipid homeostasis. Many of these findings pre-date the use of antipsychotic drugs (APDs) which on their own are also strongly associated with metabolic side effects. The combination of APD-induced metabolic changes and common adverse environmental factors associated with schizophrenia have made it difficult to determine the specific contributions of each to the overall metabolic picture. Data from drug-naïve patients, both from the pre-APD era and more recently, suggest that there may be an intrinsic metabolic risk associated with schizophrenia. Nevertheless, these findings remain controversial due to significant clinical variability in both psychiatric and metabolic symptoms throughout patients' disease courses. Here, we provide an extensive review of classic and more recent literature describing the metabolic phenotype associated with schizophrenia. We also suggest potential mechanistic links between signaling pathways associated with schizophrenia and metabolic dysfunction. We propose that, beyond its symptomatology in the central nervous system, schizophrenia is also characterized by pathophysiology in other organ systems directly related to metabolic control.

Efficacy and safety of adjunctive topiramate for schizophrenia: a meta-analysis of randomized controlled trials

OBJECTIVE

To systematically examine the randomized controlled trial (RCT) evidence regarding efficacy and tolerability of topiramate cotreatment with antipsychotics in schizophrenia-spectrum disorders.

METHODS

Random-effects meta-analysis of RCTs of topiramate cotreatment with antipsychotics vs. placebo/ongoing antipsychotic treatment in schizophrenia-spectrum disorders. Standardized or weighted mean difference (SMD/WMD), risk ratio (RR) ±95% confidence intervals (CIs), and number needed to harm (NNH) were calculated.

RESULTS

Across 16 RCTs (n = 934, duration = 11.8 ± 5.6 weeks), topiramate outperformed the comparator regarding change/endpoint of total (SMD: -0.58, 95% CI: -0.82, -0.35, P < 0.00001), positive (SMD: -0.37, 95% CI: -0.61, -0.14, P = 0.002), negative (SMD: -0.58, 95% CI: -0.87, -0.29, P < 0.0001), and general symptoms (SMD: -0.68, 95% CI: -0.95, -0.40, P < 0.00001). Furthermore, topiramate was superior regarding body weight (WMD: -2.75 kg, 95% CI: -4.03, -1.47, P < 0.0001), body mass index (BMI) (WMD: -1.77, 95% CI: -2.38, -1.15, P < 0.00001), triglycerides (P = 0.006), and insulin levels (P < 0.00001). Superiority regarding psychopathology and body weight/BMI was consistent across Chinese/Asian and Western RCTs, double-blind and open designs, clozapine and non-clozapine cotreatment, augmentation and co-initiation RCTs, and higher and lower quality RCTs. In meta-regression analyses, topiramate's efficacy for total symptoms was moderated by shorter illness duration (P = 0.047), while weight loss was greater in prevention/co-initiation vs. intervention/augmentation RCTs (-4.11 kg, 95% CI: -6.70, -1.52 vs. -1.41 kg, 95% CI: -2.23, -0.59, P < 0.001). All-cause discontinuation was similar between topiramate and comparators (RR: 1.28, 95% CI: 0.91, 1.81, P = 0.16). While topiramate led to more concentration/attention difficulties (P = 0.03, NNH = 8, 95% CI=4-25), psychomotor slowing (P = 0.02, NNH = 7, 95% CI = 4-25), and paresthesia (P = 0.05, NNH = 2, 95% CI = 4-33), it led to less ≥7% weight gain (P = 0.0001, NNH = 2, 95% CI = 2-3) and constipation (P = 0.04, NNH = 9, 95% CI = 5-100) than the comparator.

CONCLUSIONS

These results indicate that adjunctive topiramate to antipsychotics is an effective and safe treatment choice for symptomatic improvement and weight reduction in patients with schizophrenia-spectrum disorders.

A systematic review and meta-analysis of randomised controlled trials of treatments for clozapine-induced obesity and metabolic syndrome

Metabolic complications are commonly found in people treated with clozapine. Reviews on the management of this problem have generally drawn conclusions by grouping different types of studies involving patients treated with various different antipsychotics. We carried out a systematic review and meta-analysis of pharmacological and non-pharmacological treatments for clozapine-induced obesity or metabolic syndrome. Two researchers independently searched PubMed and Embase for randomised controlled trials (RCTs) of treatments for clozapine-induced obesity or metabolic syndrome. All other types of studies were excluded. We only included RCTs where more than 50% of participants were taking clozapine. We identified 15 RCTs. Effective pharmacological treatments for clozapine-induced obesity and metabolic syndrome include metformin, aripiprazole, and Orlistat (in men only). Meta-analysis of three studies showed a robust effect of metformin in reducing body mass index and waist circumference but no effects on blood glucose, triglyceride levels, or HDL levels. In addition, there is limited evidence for combined calorie restriction and exercise as a non-pharmacological alternative for the treatment of clozapine-induced obesity, but only in an in-patient setting. Rosiglitazone, topiramate, sibutramine, phenylpropanolamine, modafinil, and atomoxetine have not shown to be beneficial, despite reports of efficacy in other populations treated with different antipsychotics. We conclude that randomised-controlled trial data support the use of metformin, aripiprazole, and Orlistat (in men only) for treating clozapine-induced obesity. Calorie restriction in combination with an exercise programme may be effective as a non-pharmacological alternative. Findings from trials in different populations should not be extrapolated to people being treated with clozapine.

Memantine augmentation in clozapine-refractory schizophrenia: a randomized, double-blind, placebo-controlled crossover study

BACKGROUND

Dysfunction of neuroplasticity due to N-methyl-d-aspartate (NMDA) receptor hypofunction may be a causal factor for memory and executive dysfunctioning in schizophrenia. Deregulation of NMDA transmission in the prefrontal cortex may also explain negative and positive symptoms. Clozapine augmentation with memantine targets altered NMDA receptor-mediated neurotransmission in schizophrenia and showed substantial beneficial effects on several symptom domains in a small proof-of-concept study. We evaluate effects of memantine add-on treatment to clozapine for memory and executive function, and negative and positive symptoms in schizophrenia.

METHOD

Clozapine-treated patients with refractory schizophrenia were randomly assigned to 12 weeks of double-blind adjunctive treatment with memantine (n = 26) or placebo (n = 26). Crossover occurred after a 2-week placebo wash-out period. Primary endpoints were change from baseline to 12 weeks treatment and 14 weeks to 26 weeks treatment on memory and executive function using the Cambridge Neuropsychological Test Automated Battery (CANTAB), Positive and Negative Syndrome Scale (PANSS), and Clinical Global Impression Severity Scale (CGI-S). Side effects were assessed using the Liverpool University Neuroleptic Side-Effect Rating Scale.

RESULTS

When compared with placebo, memantine improved a composite memory score comprising verbal recognition memory and paired associates learning task scores on the CANTAB (effect size = 0.30) and PANSS negative subscale score (effect size = 0.29). Side effects were mild and transient.

CONCLUSIONS

In patients with clozapine-treated refractory schizophrenia, memantine addition significantly improved verbal and visual memory and negative symptoms without serious adverse effects. These results justify further investigations on long-term memantine augmentation to clozapine in treatment-resistant schizophrenia.

Efficacy and tolerability of topiramate-augmentation therapy for schizophrenia: a systematic review and meta-analysis of randomized controlled trials

This study aimed to perform a comprehensive meta-analysis of topiramate-augmentation therapy in patients with schizophrenia receiving antipsychotic agents. Data published up to June 20, 2016 were obtained from the PubMed, PsycINFO, and Cochrane Library databases. Twelve randomized controlled trials comparing topiramate to placebo or antipsychotic only were included (n=676 patients). The primary outcome was change in overall symptoms. Relative risk (RR) and standardized mean difference (SMD), along with 95% confidence intervals, were calculated using random effects model for each outcome. Topiramate-augmentation therapy was superior to the control for decreasing overall symptoms (SMD -0.55, 95% confidence interval -0.86 to -0.24; P=0.001; I²=55%, eight comparisons, n=380), positive symptoms (SMD -0.4), negative symptoms (SMD -0.47), and Positive and Negative Syndrome Scale general subscale scores (SMD -0.67). Furthermore, topiramate-augmentation therapy decreased weight (SMD -0.69) and body mass index (SMD -0.95) compared with the control. Topiramate was similar to the control with respect to discontinuation due to all causes (RR 1.19), inefficacy (RR 1.71), and adverse events (RR 1.09). Topiramate was associated with higher incidence of paresthesia (RR 2.67) and attention difficulty (RR 8.97) compared with the control. Our results seemed to suggest that topiramate-augmentation therapy improves the psychopathology of schizophrenia with good tolerability and has the additional advantage of weight maintenance. However, because there were some limitations (numbers of studies and patients included in the meta-analysis were small, some studies used completer analysis, Chinese studies were included in the meta-analysis, and studies that had a risk of bias were included in the meta-analysis) in this study, we cannot apply the results of this study in daily clinical practice.

Glutamatergic agents for schizophrenia: current evidence and perspectives

Suboptimal outcomes in schizophrenia are a consequence of lacking insight into the etiology, biomarkers and treatment-relevant subgroups, the therapeutic restriction to dopaminergic-modulating antipsychotics that fail to significantly improve negative and cognitive symptoms, non-adherence, and, in the case of treatment-resistance, the underutilization of clozapine. Evidence suggests additional, extra-dopaminergic abnormalities in amino acid neurotransmission, particularly the glutamatergic system. Antidopaminergic antipsychotics modulate this system on several levels, as do mood stabilizers, including lamotrigine, topiramate and pregabaline. Recently, agonists at metabotropic glutamate receptors and glycine uptake inhibitors failed in large placebo-controlled trials for schizophrenia. Problems to overcome for successfully leveraging glutamatergic agents for schizophrenia are patient selection, focus on positive symptoms and late disease stages, and dose-response relationships. Because glutamate guides processes of brain development and maturation, clinical research should focus on the at-risk mental state or first-episode psychosis, address cognition and negative symptoms and use monotherapy designs in parallel to augmentation strategies.

Efficacy and safety of sertindole in schizophrenia: a clinical review

Sertindole is an atypical antipsychotic reintroduced into the European market in 2005 after a reevaluation of its risks and benefits, under the agreement that close electrocardiographic screening would be conducted. It has a high affinity for dopamine D2, serotonin 5-HT2A and 5-HT2C, and α1 adrenergic receptors. Moreover, sertindole shows modest affinity for H1-histaminergic and muscarinic receptors. The pharmacological properties, clinical efficacy, safety, and tolerability of sertindole are covered in this article based on a literature review from 1990 to 2014. Given current available findings, sertindole is at least effective as haloperidol, risperidone, and olanzapine on schizophrenia symptoms. Regarding its efficacy on cognitive symptoms, sertindole effect is supported by both preclinical and clinical studies versus haloperidol and olanzapine; however, its role on cognition needs further clarification. Concerning safety and tolerability issues, sertindole is characterized by a low potential to cause sedation and extrapyramidal symptoms, and by an acceptable metabolic profile; nevertheless, cardiac safety remains a major concern, and the electrocardiographic monitoring should be carried out during treatment to substantially reduce cardiovascular risk. In conclusion, although it has an equivalent profile compared to other antipsychotic drugs, sertindole actually remains a second-line choice for schizophrenic patients intolerant to at least one other antipsychotic agent.

Schizophrenia: when clozapine fails

PURPOSE OF REVIEW

This article reviews the recent evidence for therapeutic strategies for patients with treatment-resistant schizophrenia (TRS) not responding to or only partially responding to clozapine.

RECENT FINDINGS

A number of pharmacological and nonpharmacological biological approaches for clozapine-resistant TRS have been evaluated in clinical trials. Among these, the evidence supporting clozapine augmentation by pharmacological approaches is weak and the reported benefits were modest at best. However, the results of a recent randomized trial suggest that electroconvulsive therapy (ECT) may be efficacious for the short-term treatment of patients with clozapine-resistant TRS.

SUMMARY

There is currently insufficient evidence for efficacy of pharmacological augmentation strategies to clozapine. ECT may be a promising option, but further research is necessary to confirm its long-term effects. Moreover, further controlled studies are warranted to clarify the potential of other biological and psychosocial approaches to serve as adjuvant treatments in patients with clozapine-resistant TRS.

Efficacy of adjunctive treatments added to olanzapine or clozapine for weight control in patients with schizophrenia: a systematic review and meta-analysis

Objectives. This study was conducted to review systematically adjunctive treatments for weight reduction in patients with schizophrenia and compare efficacies of clinical trials through meta-analysis, so as to provide effective clinical guideline regarding weight control for patients taking atypical antipsychotics. Methods. Candidate clinical trials were identified through searching the Cochrane Central Register of Controlled Trials, PubMed, and PsycINFO. Fourteen randomized clinical trials were included for systematic review and meta-analysis from 132 potential trials. The Comprehensive Meta-Analysis version 2 was used for meta-analysis. Results. Difference in means and significances from meta-analyses regarding weight control by adjunctive treatments showed that topiramate, aripiprazole, or sibutramine was more effective than metformin or reboxetine. Psychiatric evaluations did not show statistically significant changes between treatment groups and placebo groups except topiramate adjunctive treatments. Adverse effects regarding adjunctive therapies were tolerable and showed statistically no significances compared to control groups. Conclusion. Though having several reports related to exacerbation of psychiatric symptoms, topiramate and aripiprazole are more efficacious than other medications in regard to weight reduction and less burden of critical adverse effects as well as being beneficial for clinical improvement.

New therapeutic approaches for treatment-resistant schizophrenia: a look to the future

Schizophrenia for many patients is a lifelong mental disorder with significant consequences on most functional domains. One fifth to one third of patients with schizophrenia experience persistent psychotic symptoms despite adequate trials of antipsychotic treatment, and are considered to have treatment-resistant schizophrenia (TRS). Clozapine is the only medication to demonstrate efficacy for psychotic symptoms in such patients. However, clozapine is not effective in 40%-70% of patients with TRS and it has significant limitations in terms of potentially life-threatening side effects and the associated monitoring. Accordingly, a number of pharmacological and non-pharmacological biological approaches for clozapine-resistant TRS have emerged. This article provides a brief updated critical review of recent therapeutic strategies for TRS, particularly for clozapine-resistant TRS, which include pharmacotherapy, electroconvulsive therapy, repetitive transcranial magnetic stimulation, and transcranial direct current stimulation.

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.

Augmentation of clozapine with amisulpride: an effective therapeutic strategy for violent treatment-resistant schizophrenia patients in a UK high-security hospital

OBJECTIVE

Clozapine is used in the management of treatment-resistant schizophrenia and is effective in reducing aggression; however a subgroup of patients is poorly responsive. For violent patients in this group, there is limited literature on the use of strategies to augment clozapine with other agents. Here we present a case series of 6 schizophrenia patients, within a high-security hospital, who have a history of serious violence and who were treated with clozapine augmented with amisulpride.

METHODS

We reviewed case notes and health records for evidence of violence/aggression and positive factors such as engagement in activities, and Clinical Global Impression (CGI) scores were formulated. We also examined metabolic parameters before and after augmentation.

RESULTS

All 6 of the patients showed clinical improvement in symptoms and a reduction in their risk of violence to others. Five patients had a reduction in number of violent/aggressive incidents, and all patients showed improvement in engagement in occupational, vocational, and/or psychological work. Metabolic parameters were largely unchanged except for 1 patient whose Body Mass Index (BMI) increased. Five patients reported side effects as unchanged or improved.

CONCLUSION

These schizophrenia patients with a history of violence showed clinical improvement and reduced aggression and violence with amisulpride augmentation of clozapine. To our knowledge, this is the first report of an antiaggressive benefit of this combination in forensic psychiatric patients. Further studies are warranted to establish the efficacy and anti-aggressive effects of amisulpride augmentation of clozapine.

Reboxetine adjuvant therapy in patients with schizophrenia showing a suboptimal response to clozapine: a 12-week, open-label, pilot study

The present 12-week open-label uncontrolled trial was aimed to explore the efficacy of reboxetine add-on pharmacotherapy on clinical symptoms and cognitive functioning in 15 patients with schizophrenia with suboptimal response (mean [SD] Brief Psychiatric Rating Scale baseline total score, 32.2 [5.4]) despite receiving clozapine monotherapy at the highest tolerated dosage. The results obtained evidenced that reboxetine at a dosage of 4 mg/d mildly reduced only depressive symptoms (Calgary Depression Scale for Schizophrenia: P = 0.035, Cohen d = 0.7), whereas worsening of performances on phonemic fluency (P = 0.012, Cohen d = 0.5) was observed. After Bonferroni correction, changes at the Calgary Depression Scale for Schizophrenia and at the Verbal Fluency Task were not further confirmed.The results obtained indicate that reboxetine seemed to be scarcely effective for reducing clinical symptoms in patients with schizophrenia who have had an incomplete clinical response to clozapine. Regarding cognitive functioning, in our sample, a trend to experience cognitive impairment in the examined domains was observed, as confirmed by a mild worsening of performances on cognitive tasks.Schizophrenia is a heterogeneous disorder with regard to pathophysiology; therefore, data reflecting the mean response of a sample of patients may fail to reveal therapeutic effects. More research is needed to better identify subgroups of patients with peculiar features, which may account for responsivity to experimental medications and augmentation strategies.

Augmentation of clozapine with agomelatine in partial-responder schizophrenia: a 16-week, open-label, uncontrolled pilot study

The present 16-week open-label uncontrolled trial was aimed to explore the efficacy of adjunctive agomelatine on clinical symptoms and cognitive functioning in 20 schizophrenia patients showing partial response (Brief Psychiatric Rating Scale, mean [SD] baseline total score = 37.5 [6.6]) to clozapine monotherapy at the highest tolerated dosage. The results obtained evidenced that agomelatine at a dosage of 50 mg/d was associated with score reduction in all Positive and Negative Syndrome Scale domains (positive, P = 0.011 and Cohen d = 0.7; negative, P < 0.0001 and Cohen d = 1.1; psychopathology, P = 0.001 and Cohen d = 0.9) and total score (P = 0.001, Cohen d = 1.2), depressive (Calgary Depression Scale for Schizophrenia, P = 0.013 and Cohen d = 0.6), and overall clinical symptoms (Brief Psychiatric Rating Scale, P = 0.001 and Cohen d = 0.6 ); moreover, improved performances on Stroop task (P = 0.006, Cohen d = 0.7) and Wisconsin Card Sorting Test "perseverative errors" (P = 0.033, Cohen d = 0.3) were observed. The favorable effect of agomelatine on clinical and cognitive symptoms was encouraging, and more research is needed to better identify subgroups of patients who are partially responsive to clozapine monotherapy in which agomelatine augmentation may be of benefit.

Pharmacological Interventions for the MATRICS Cognitive Domains in Schizophrenia: What's the Evidence?

Schizophrenia is a disabling, chronic psychiatric disorder with a prevalence rate of 0.5-1% in the general population. Symptoms include positive (e.g., delusions, hallucinations), negative (e.g., blunted affect, social withdrawal), as well as cognitive symptoms (e.g., memory and attention problems). Although 75-85% of patients with schizophrenia report cognitive impairments, the underlying neuropharmacological mechanisms are not well understood and currently no effective treatment is available for these impairments. This has led to the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) initiative, which established seven cognitive domains that are fundamentally impaired in schizophrenia. These domains include verbal learning and memory, visual learning and memory, working memory, attention and vigilance, processing speed, reasoning and problem solving, and social cognition. Recently, a growing number of studies have been conducted trying to identify the underlying neuropharmacological mechanisms of cognitive impairments in schizophrenia patients. Specific cognitive impairments seem to arise from different underlying neuropharmacological mechanisms. However, most review articles describe cognition in general and an overview of the mechanisms involved in these seven separate cognitive domains is currently lacking. Therefore, we reviewed the underlying neuropharmacological mechanisms focusing on the domains as established by the MATRICS initiative which are considered most crucial in schizophrenia.

Psychopharmacologic treatment of psychosis in children and adolescents: efficacy and management

The efficacy of antipsychotic use in children and adolescents with psychosis has been shown in an increasing number of randomized controlled trials. Chronic use of second-generation and third-generation antipsychotics has the potential for significant side effects, especially metabolic syndrome. A review of the literature on side effect profiles of antipsychotic medications used in children and adolescents is provided to help clinicians develop treatment plans for their patients. Clozapine has the best efficacy of all antipsychotic medications in adults as well as children and adolescents who are treatment resistant. Guidance is provided for the management of clozapine side effects.

Antiepileptic drug effects on mood and behavior: molecular targets

With almost 100 years of clinical experience, antiepileptic drugs (AEDs) remain the mainstay of epilepsy treatment. They suppress epileptic seizures by acting on a variety of mechanisms and molecular targets involved in the regulation of neuronal excitability. These include inhibitory-GABAergic and excitatory-glutamatergic neurotransmission, as well as ion (sodium and calcium) conductance through voltage-gated channels. On the other hand, accruing evidence indicates that these mechanisms and targets are also implicated in the regulation of mood and behavior, which may explain why each AED is associated with specific psychotropic effects. These effects, however, cannot be explained solely on the basis of the known mode of action of each AED, and other mechanisms or targets are likely to be implicated. In this article, we review positive and negative effects of AEDs on mood and behavior, discuss putative underlying mechanisms, and highlight knowledge gaps which should be addressed in future studies.

Polypharmacy for schizophrenia

PURPOSE OF REVIEW

Combining psychotropic medications is common for people diagnosed with schizophrenia facing a variety of clinical circumstances. This review provides an update on evidence regarding the effectiveness of polypharmacy approaches.

RECENT FINDINGS

Epidemiology studies have demonstrated that polypharmacy is extremely common, but evidence regarding all polypharmacy approaches for schizophrenia from randomized controlled trials remains scarce. Combinations of antipsychotic medicines are unsupported by evidence. Antidepressants are commonly used to treat depressive symptoms; this logical role for antidepressants has little support from randomized controlled trials (RCTs) but may be associated with lower suicide and all-cause mortality. Insufficient evidence supports the use of benzodiazepines for schizophrenia; possible risks of benzodiazepines, including increased mortality rates revealed in observational studies, warrant caution and further study.

SUMMARY

The lack of evidence regarding common treatment strategies exacerbates the tremendous challenge of providing optimal pharmacotherapy for individuals with schizophrenia. Comparative effectiveness research, using observational methods when appropriate and RCTs when possible, is needed to inform clinical practice, use resources wisely and improve outcomes.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for biological treatment of schizophrenia, part 2: update 2012 on the long-term treatment of schizophrenia and management of antipsychotic-induced side effects

Abstract These updated guidelines are based on a first edition of the World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for biological treatment of schizophrenia published in 2006. For this 2012 revision, all available publications pertaining to the biological treatment of schizophrenia were reviewed systematically to allow for an evidence-based update. These guidelines provide evidence-based practice recommendations that are clinically and scientifically meaningful. They are intended to be used by all physicians diagnosing and treating people suffering from schizophrenia. Based on the first version of these guidelines, a systematic review of the MEDLINE/PUBMED database and the Cochrane Library, in addition to data extraction from national treatment guidelines, has been performed for this update. The identified literature was evaluated with respect to the strength of evidence for its efficacy and then categorised into six levels of evidence (A-F) and five levels of recommendation (1-5) ( Bandelow et al. 2008a ,b, World J Biol Psychiatry 9:242, see Table 1 ). This second part of the updated guidelines covers long-term treatment as well as the management of relevant side effects. These guidelines are primarily concerned with the biological treatment (including antipsychotic medication and other pharmacological treatment options) of adults suffering from schizophrenia.

Pharmacological augmentation strategies for schizophrenia patients with insufficient response to clozapine: a quantitative literature review

BACKGROUND

When schizophrenia patients have insufficient response to clozapine, pharmacological augmentation is often applied. This meta-analysis summarizes available evidence on efficacy of pharmacological augmentation of clozapine treatment in schizophrenia spectrum disorder.

METHODS

Only double-blind randomized controlled studies were included. Primary outcome measure was total symptom severity, and secondary outcome measures were subscores for positive and negative symptoms. Effect sizes were calculated from individual studies and combined to standardized mean differences (Hedges's g).

RESULTS

Twenty-nine studies reporting on 15 different augmentations were included. Significant better efficacy than placebo on total symptom severity was observed for lamotrigine, citalopram, sulpiride, and CX516 (a glutamatergic agonist). The positive effect of lamotrigine disappeared after outlier removal. The other positive findings were based on single studies. Significantly better efficacy on positive symptom severity was observed for topiramate and sulpiride. The effect of topiramate disappeared after outlier removal. Results for sulpiride were based on a single randomized controlled trial. Citalopram, sulpiride, and CX516 showed better efficacy for negative symptoms than placebo, all based on single studies.

CONCLUSIONS

Evidence for efficacy of clozapine augmentation is currently scarce. Efficacy of lamotrigine and topiramate were both dependent on single studies with deviating findings. The effect of citalopram, sulpiride, and CX516 were based on single studies. Thus, despite their popularity, pharmacological augmentations of clozapine are not (yet) demonstrated to be superior to placebo.

Beyond dopamine: glutamate as a target for future antipsychotics

The dopamine hypothesis of schizophrenia remains the primary theoretical framework for the pharmacological treatment of the disorder. Despite various lines of evidence of dopaminergic abnormalities and reasonable efficacy of current antipsychotic medication, a significant proportion of patients show suboptimal treatment responses, poor tolerability, and a subsequent lack of treatment concordance. In recent decades, intriguing evidence for the critical involvement of other neurotransmitter systems in the pathophysiology of schizophrenia has emerged, most notably of dysfunctions within the glutamate pathways. Consequently, the glutamate synapse has arisen as a promising target for urgently needed novel antipsychotic compounds—particularly in regards to debilitating negative and cognitive symptoms poorly controlled by currently available drugs. In this paper, recent findings integrating glutamatergic and dopaminergic abnormalities in schizophrenia and their implications for novel pharmacological targets are discussed. An overview of compounds in various stages of development is given: drugs enhancing NMDA receptor function as well as metabotropic glutamate receptor (mGluR) agonist and positive allosteric modulators (PAMs) are emphasised. Together with other agents more indirectly affecting glutamatergic neurotransmission, their potential future role in the pharmacotherapy of schizophrenia is critically evaluated.

World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for Biological Treatment of Schizophrenia, part 1: update 2012 on the acute treatment of schizophrenia and the management of treatment resistance

These updated guidelines are based on a first edition of the World Federation of Societies of Biological Psychiatry Guidelines for Biological Treatment of Schizophrenia published in 2005. For this 2012 revision, all available publications pertaining to the biological treatment of schizophrenia were reviewed systematically to allow for an evidence-based update. These guidelines provide evidence-based practice recommendations that are clinically and scientifically meaningful and these guidelines are intended to be used by all physicians diagnosing and treating people suffering from schizophrenia. Based on the first version of these guidelines, a systematic review of the MEDLINE/PUBMED database and the Cochrane Library, in addition to data extraction from national treatment guidelines, has been performed for this update. The identified literature was evaluated with respect to the strength of evidence for its efficacy and then categorised into six levels of evidence (A-F; Bandelow et al. 2008b, World J Biol Psychiatry 9:242). This first part of the updated guidelines covers the general descriptions of antipsychotics and their side effects, the biological treatment of acute schizophrenia and the management of treatment-resistant schizophrenia.

Treatment-resistant Schizophrenia: Evidence-based Strategies

Treatment-resistant symptoms complicate the clinical course of schizophrenia, and a large proportion of patients do not reach functional recovery. In consequence, polypharmacy is frequently used in treatment-refractory cases, addressing psychotic positive, negative and cognitive symptoms, treatment-emergent side effects caused by antipsychotics and comorbid depressive or obsessive-compulsive symptoms. To a large extent, such strategies are not covered by pharmacological guidelines which strongly suggest antipsychotic monotherapy. Add-on strategies comprise combinations of several antipsychotic agents and augmentations with mood stabilizers; moreover, antidepressants and experimental substances are applied. Based on the accumulated evidence of clinical trials and meta-analyses, combinations of clozapine with certain second-generation antipsychotic agents and the augmentation of antipsychotics with antidepressants seem recommendable, while the augmentation with mood stabilizers cannot be considered superior to placebo. Forthcoming investigations will have to focus on innovative pharmacological agents, the clinical spectrum of cognitive deficits and the implementation of cognitive behavioral therapy.

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.