Clozapine resistant schizophrenia: Newer avenues of management

Overview of Novel Antipsychotic Drugs: State of the Art, New Mechanisms, and Clinical Aspects of Promising Compounds

Antipsychotic medications are a vast class of drugs used for the treatment of psychotic disorders such as schizophrenia. Although numerous compounds have been developed since their introduction in the 1950s, several patients do not adequately respond to current treatments, or they develop adverse reactions that cause treatment discontinuation. Moreover, in the past few decades, discoveries in the pathophysiology of psychotic disorders have opened the way for experimenting with novel compounds that have alternative mechanisms of action, with some of them showing promising results in early trials. The scope of this review was to summarize the novel antipsychotics developed, their current experimental status, and their mechanisms of action. In particular, we analyzed the main classes of investigational antipsychotics, such as monoamine, glutamate, acetylcholine, cannabinoid receptor modulators, enzyme inhibitors, ion channel modulators, and mixed receptor modulators. In addition, the safety profiles and adverse effects of these drugs were carefully evaluated, considering the relevance of these aspects for patients' drug adherence and quality of life, especially in the long-term treatment. Lastly, we tried to understand which compounds have greater potential to be approved by the principal drug regulatory agencies in the next years and if they could be used for diseases other than psychotic disorders.

An Investigation of the Sodium Nitroprusside Effects on Serum Lipids in an Animal Model of Schizophrenia by the Magnetic Resonance Study

Schizophrenia (SCZ) is a multifactorial mental illness with limited knowledge concerning pathogenesis, contributing to the lack of effective therapies. More recently, the use of a nitric oxide donor named sodium nitroprusside (sNP) was suggested as a potential therapeutic drug for the treatment of SCZ. Despite the mixed results regarding the effectiveness of the sNP in reducing SCZ symptoms, successful trials on sNP in treatment-resistant SCZ were published. We have also demonstrated the power of evaluating the lipidic profiles of human clinical and animal model samples to identify the biomarkers of the pharmacological response to the diagnosis of mental disorders. Aim of this work is to evaluate the sNP effects in an animal model for SCZ studies through lipidomic profiles assessed by magnetic resonance spectroscopy (NMR). Lipidic profiling of serum from these animals indicated a more pronounced effect of sNP on lipids in the 0.50-6.00 ppm spectral region. Chemometric analysis also indicated an approximation of the lipidic profiling of SCZ animal model rats treated with sNP compared to that of the control group. In addition, we have compared the sNP treatment with other antipsychotics classically used in the clinic, such as haloperidol and clozapine, and the sNP treatment evaluated herein confirms the potential of sNP for the treatment of SCZ.

Neurostructural changes in schizophrenia and treatment-resistance: a narrative review

Schizophrenia is a complex disorder characterized by multiple neurochemical abnormalities and structural changes in the brain. These abnormalities may begin before recognizable clinical symptoms appear and continue as a dynamic process throughout the illness. Recent advances in imaging techniques have significantly enriched our comprehension of these structural alterations, particularly focusing on gray and white matter irregularities and prefrontal, temporal, and cingulate cortex alterations. Some of the changes suggest treatment resistance to antipsychotic medications, while treatment nonadherence and relapses may further exacerbate structural abnormalities. This narrative review aims to discuss the literature about alterations and deficits within the brain, which could improve the understanding of schizophrenia and how to interpret neurostructural changes.

Evaluation of the pharmacodynamic interaction effect of augmentation agents with clozapine in patients with treatment-resistant schizophrenia: A simulation study of clinical data

INTRODUCTION

The aim of the study was to evaluate interaction effect of various augmentation strategies with clozapine in patients with Treatment-resistant schizophrenia.

METHODS

Data was extracted for change in positive and negative syndrome scale (PANSS) or brief psychiatric rating scale (BPRS) scores for monotherapy with various antipsychotic agents alone and their combination with clozapine. Individual patient data was generated using simulation of data (factorial trial framework) from published clinical trials for sample sizes from eight to 400 to evaluate interaction effect through linear modeling. Dose equivalents were calculated, and best fit models were determined for simulated data.

RESULTS

The polynomial model was found to be the best fit for the simulated data to determine interaction effect of combination. The clozapine augmentation with risperidone and ziprasidone was found to be antagonistic, whereas it was additive for haloperidol, aripiprazole, and quetiapine. A synergistic effect was observed for ECT combined with clozapine (Interaction effect: -7.62; p <0.001). A sample size of 250-300 may be sufficient to demonstrate a clinically significant interaction in future trials.

CONCLUSION

Clozapine may be augmented with electroconvulsive therapy, leading to the enhancement of antipsychotic effect. Though some antipsychotics like aripiprazole demonstrate additive effects, they may also add to the adverse effects.

The Advantages of Combining Therapies in Treating Psychiatric Patients

Mental illnesses are among the leading causes of morbidity and disability worldwide, and the burden associated with these disorders has increased steadily over the past three decades [...].

Evaluation of Global Dystonia Rating Scale as a predictor of unfavorable outcomes among acute antipsychotics poisoned patients

Worldwide, acute antipsychotic poisoning results in high morbidities and mortalities. Though extrapyramidal syndromes are commonly associated, the extent of extrapyramidal syndromes in relation to the severity of antipsychotic poisoning has not been addressed yet. Thus, this study aimed to assess the Global Dystonia Rating Scale (GDRS) as an unfavorable outcomes predictive tool in acute antipsychotic poisoning. A cross-sectional study included 506 antipsychotic-poisoned patients admitted to Tanta University Poison Control Center, Egypt, over three years was conducted. The mean GDRS was 9.1 ± 16.7 in typical antipsychotic poisoning, which was significantly higher than that of atypical antipsychotics (4.2 ± 11.5) (p = 0.003). Patients with GDRS> 20 showed significantly higher liability for all adverse outcomes (p < 0.05). However, poisoning with typical antipsychotics was associated with significantly more cardiotoxicity (p = 0.042), particularly prolonged QRS (p = 0.005), and intensive care unit (ICU) admission (p = 0.000). In contrary to the PSS, which failed to predict the studied adverse outcomes, GDRS significantly predicted all adverse outcomes (p < 0.000) for all antipsychotic generations. In atypical antipsychotics, GDRS above three accurately predicted cardiotoxicities, prolonged QTc interval, and respiratory failure with Area under curves (AUC) of 0.937, 0.963, and 0.941, respectively. In typical antipsychotic poisoning, at higher cutoffs (7.5, 27.5, 18, and 7.5), cardiotoxicities, prolonged QTc interval, and respiratory failure were accurately predicted (AUC were 0.974, 0.961, and 0.960, respectively). GDRS is an objective, substantially useful tool that quantifies dystonia and can be used as an early reliable predictor of potential toxicity in acute antipsychotic poisoning.

Is antipsychotic augmentation associated with improved functioning in patients on clozapine?

OBJECTIVE

We aimed at exploring the relationship between functional outcomes in patients on clozapine augmented with antipsychotics in treatment-resistant schizophrenia using standard outcome measures Health of Nation Outcome Scales (HoNOS) and Life Skills Profile (LSP-16).

METHOD

In a cross-sectional study of 83 patients on clozapine treated in a psychiatric rehabilitation hospital, the association between the primary outcome measure, LSP-16 including its subscales, and treatment with antipsychotic augmentation (AA) were analysed using linear regression.

RESULT

The presence of moderate-to-severe positive symptoms on the HoNOS 6 dichotomised item measure was the only statistically significant predictor of functional impairment as determined by total LSP-16 score.The group of patients with ongoing positive symptoms (partial responders) were characterised by higher total LSP-16 scores, higher numbers of AA agents, and higher chlorpromazine equivalence. There was an inverse linear relationship between chlorpromazine equivalence of AA and total score of LSP-16 scale in the group of partial responders.

CONCLUSION

Augmentation with other antipsychotic agents was associated with higher functioning in a cross-sectional study of patients with schizophrenia with poor response of positive symptoms to clozapine. This might be an important clinical factor to consider when prescribing antipsychotics to patients with clozapine-resistant schizophrenia.

Assessing NH300094, a novel dopamine and serotonin receptor modulator with cognitive enhancement property for treating schizophrenia

Background: Schizophrenia is a serious psychiatric disorder that significantly affects the quality of life of patients. The objective of this study is to discover a novel antipsychotic candidate with highly antagonistic activity against both serotonin and dopamine receptors, demonstrating robust efficacy in animal models of positive, negative, and cognitive symptoms of schizophrenia. Methods: In the present study, we examined the activity of antipsychotic drug (NH300094) on 5-HT2A, 5-HT2C, 5-HT1A, 5-HT1B, 5-HT7, H1, M1, Alpha1A, D2L, D2S, Alpha2A, D3 receptor functional assay in vitro. In addition, multiple animal models, including dizocilpine (MK-801) induced hyper-locomotion; APO induced climbing; Conditioned Avoidance Response (CAR); DOI-Induced Head Twitch; Forced swimming test; Scopolamine induced cognitive impairment model, were used to verify the antipsychotic activity of NH300094 in preclinical. Results: In vitro functional assays have indicated that NH300094 is a potent antagonist of 5-HT receptors and dopamine receptors, with higher relative antagonistic activity against 5-HT2A receptor (5-HT2A IC50 = 0.47 nM) than dopamine receptors (D2L IC50 = 1.04 nM; D2S IC50 = 11.71 nM; D3 IC50 = 31.55 nM). Preclinical in vivo pharmacological study results showed that NH300094 was effective in multiple models, which is more extensive than the clinic drug Risperidone. Furthermore, the safety window for extrapyramidal side effects of NH300094 is significantly wider than that of Risperidone (For NH300094, mice catalepsy model ED50/ Mice MK-801 model ED50 = 104.6-fold; for Risperidone, mice catalepsy model ED50/ Mice MK-801 model ED50 = 12.9-fold), which suggests a potentially better clinical safety profile for NH300094. Conclusion: NH300094 is a novel potent serotonin and dopamine receptors modulator, which has good safety profile and therapeutic potential for the treatment of schizophrenia with cognition disorders.

Cariprazine augmentation of clozapine in schizophrenia-a retrospective chart review

The aim of our study was to evaluate the efficacy of cariprazine augmentation of clozapine in treatment-resistant schizophrenia in a retrospective chart review. Among 916 medical records of schizophrenia patients, we identified 12 individuals treated with a combination of those drugs for a duration of 3-60 weeks [median 32 (10-40)]. Clinical Global Impression-Improvement (CGI-I) scores were used to measure the treatment response between the introduction of cariprazine augmentation of clozapine and the last point of observation. The majority of the patients presented treatment response (9/12 patients, 75%) after 4-16 weeks of therapy [median 6 (4-12)]. Treatment was associated with the decrease in positive, negative, affective, and anxiety symptom severity, as well as improvement of patient global functioning. One patient discontinued the treatment due to side effects (akathisia), and two patients halted the therapy due to the exacerbation of psychotic symptoms. Our study presents a thorough clinical description of the largest number of treatment-resistant schizophrenia patients medicated using cariprazine augmentation of clozapine in a "real-world" setting. Our results suggest that the use of this combination may lead to the improvement in a broad range of symptoms of patients with this condition.

Enhancing Predictive Power: Integrating a Linear Support Vector Classifier with Logistic Regression for Patient Outcome Prognosis in Virtual Reality Therapy for Treatment-Resistant Schizophrenia

(1) Background: Approximately 30% of schizophrenia patients are known to be treatment-resistant. For these cases, more personalized approaches must be developed. Virtual reality therapeutic approaches such as avatar therapy (AT) are currently undergoing investigations to address these patients' needs. To further tailor the therapeutic trajectory of patients presenting with this complex presentation of schizophrenia, quantitative insight about the therapeutic process is warranted. The aim of the study is to combine a classification model with a regression model with the aim of predicting the therapeutic outcomes of patients based on the interactions taking place during their first immersive session of virtual reality therapy. (2) Methods: A combination of a Linear Support Vector Classifier and logistic regression was conducted over a dataset comprising 162 verbatims of the immersive sessions of 18 patients who previously underwent AT. As a testing dataset, 17 participants, unknown to the dataset, had their first immersive session presented to the combinatory model to predict their clinical outcome. (3) Results: The model accurately predicted the clinical outcome for 15 out of the 17 participants. Classification of the therapeutic interactions achieved an accuracy of 63%. (4) Conclusion: To our knowledge, this is the first attempt to predict the outcome of psychotherapy patients based on the content of their interactions with their therapist. These results are important as they open the door to personalization of psychotherapy based on quantitative information about the interactions taking place during AT.

Schizophrenia Patients Discharged on Clozapine Plus Long-Acting Injectable Antipsychotics From a Public Psychiatric Hospital in Taiwan, 2006-2021

BACKGROUND

Some schizophrenia patients treated with clozapine experience an inadequate response and adherence problems. The purpose of this study was to compare time to rehospitalization within 6 months in schizophrenia patients discharged on 3 clozapine regimens. Additionally, the temporal trend of prescription rate in each group was also explored.

METHODS

Schizophrenia patients discharged from the study hospital from January 1, 2006, to December 31, 2021, (n = 3271) were included in the analysis. The type of clozapine prescribed at discharge was divided into 3 groups: clozapine plus long-acting injectable antipsychotics (clozapine + LAIs), clozapine plus other oral antipsychotics (clozapine + OAPs), and clozapine monotherapy. Survival analysis was used to compare time to rehospitalization within 6 months after discharge among the 3 groups. The temporal trend in the prescription rate of each group was analyzed using the Cochran-Armitage Trend test.

RESULTS

Patients discharged on clozapine + LAIs had a significantly longer time to rehospitalization than those on clozapine + OAPs or clozapine monotherapy. The prescription rates of clozapine + LAIs and clozapine + OAPs significantly increased over time, whereas the prescription rates of clozapine monotherapy significantly decreased.

CONCLUSIONS

Compared with the clozapine + OAPs group, the clozapine + LAIs group had a lower risk of rehospitalization and a lower dose of clozapine prescribed. Therefore, if a second antipsychotic is required for patients who are taking clozapine alone, LAIs should be considered earlier.

Clozapine-induced eosinophilia: A case report

Schizophrenia is a chronic neuropsychiatric illness defined by the appearance of positive, and negative symptoms and/or cognitive impairment. Antipsychotic drugs are predominantly used in the treatment of psychotic disorders, but not all patients with schizophrenia respond to every antipsychotic medication. Clozapine is one of the best atypical antipsychotics and is highly effective in treating treatment-resistant schizophrenia. Evidence suggests that clozapine appears to be effective in lowering the risk of suicide, extrapyramidal side effects, and relapse in patients with schizophrenia. Per contra, clozapine is not the first-line treatment due to its unalterable aftereffects such as agranulocytosis, metabolic syndrome, seizures, and rarely, eosinophilia. Eosinophilia can be life-threatening. Eosinophils infiltrate different tissues and cause inflammation in multiple organs causing end-organ damage. The current study aimed to report the incidence of eosinophilia associated with clozapine use in patients with schizophrenia. Literature on clozapine-induced eosinophilia is relatively scarce. Understanding the progression and management of clozapine-induced eosinophilia and its end-organ effects is imperative. While there is insufficient data about the guidelines in the management of clozapine-induced eosinophilia, this study contributes to understanding the patterns of the disease progression with clozapine dosage. A case study was done on a patient with schizophrenia and autistic spectrum disorder who was on clozapine. Data on how eosinophil levels varied with clozapine dosing was analyzed and documented. The evidence of clozapine dosage affecting eosinophil and C-reactive protein levels in this patient was summarized in a table and a narrative review.

Association Between Clozapine Plasma Concentrations and Treatment Response: A Systematic Review, Meta-analysis and Individual Participant Data Meta-analysis

BACKGROUND AND OBJECTIVES

Although therapeutic drug monitoring of clozapine is recommended, its optimisation is often adjusted only on the basis of dosage. The aim of this study was to assess the link between clozapine plasma concentrations and clinical response by a meta-analysis of published studies and by an individual participant data meta-analysis.

METHODS

We conducted a computerised search of bibliographic databases (EMBASE, PubMed, Clinical Trials, and Web of Science) to identify studies that assessed the relationship between clozapine serum or plasma concentrations and clinical efficacy. Using pooled data, we investigated the association between improvement of clinical outcome and clozapine or norclozapine plasma concentrations, the sum of clozapine and norclozapine plasma concentrations, and the coefficient of variation of clozapine plasma concentrations. Using available individual data, we assessed the relationship between clozapine plasma concentrations and clinical response (changes in the Brief Psychiatric Rating Scale score) and identified a threshold level for a favourable clinical response.

RESULTS

Fifteen studies satisfied inclusion criteria. Our meta-analysis showed that responders had clozapine plasma concentrations that were, on average, 117 ng/mL higher than non-responders. The patients with plasma clozapine concentrations above the thresholds identified in each study had a higher likelihood of responding (odds ratio = 2.94, p < 0.001). Norclozapine plasma concentrations were not associated with a clinical response. The meta-analysis of individual data supported this result and confirmed the link between clozapine concentrations and a change in the Brief Psychiatric Rating Scale score and/or the probability of clinical response. Finally, with the analysis of the coefficient of variation of clozapine plasma concentrations, we found that a greater inter-individual fluctuation in plasma concentrations was associated with a loss of clinical response.

CONCLUSIONS

Our work confirmed that, in contrast to clozapine doses, clozapine plasma concentrations were related to a favourable clinical response, with a mean difference between responders and non-responders of 117 ng/mL. A threshold for a treatment response of 407 ng/mL was determined, with a high discriminatory capacity, and a sensitivity and specificity of 71% and 89.1%, respectively.

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.

Clozapine in Treatment-Resistant Schizophrenia and Its Augmentation with Electroconvulsive Therapy in Ultra-Treatment-Resistant Schizophrenia

Clozapine is considered the gold standard for patients with treatment-resistant schizophrenia (TRS) who have previously tried other antipsychotics at adequate doses (two or more, with at least one being atypical). However, despite optimal treatment, a subgroup of TRS patients with what is known as ultra-treatment-resistant schizophrenia (UTRS) fails to respond to clozapine, which occurs in 40–70% of cases. The most common approach to manage UTRS involves augmenting clozapine with pharmacological or non-pharmacological interventions, with a growing body of evidence that supports the use of electroconvulsive therapy (ECT) as an augmenter. This prospective non-randomized 8-week study, which followed the TRIPP Working Group guidelines and is one of few that separate TRS from UTRS, aimed to evaluate the effectiveness of clozapine in TRS patients and the efficacy of ECT augmentation of clozapine in UTRS patients. Patients with TRS were assigned to receive clozapine alone (clozapine group), whereas UTRS patients received bilateral ECT in addition to their current medication regimen (ECT plus clozapine group). The severity of symptoms was evaluated using the Clinical Global Impression Scale (CGI) and Positive and Negative Syndrome Scale (PANSS) at baseline and at the end of the 8-week trial. Both treatment approaches resulted in improved CGI and PANSS scores. The results suggest that both clozapine and ECT are effective treatment options for patients with TRS and UTRS, respectively, and that adherence to guidelines should provide a better frame for future clinical studies.

Altered Patterns of Brain Glucose Metabolism Involve More Extensive and Discrete Cortical Areas in Treatment-resistant Schizophrenia Patients Compared to Responder Patients and Controls: Results From a Head-to-Head 2-[18F]-FDG-PET Study

BACKGROUND AND HYPOTHESIS

Treatment resistant schizophrenia (TRS) affects almost 30% of patients with schizophrenia and has been considered a different phenotype of the disease. In vivo characterization of brain metabolic patterns associated with treatment response could contribute to elucidate the neurobiological underpinnings of TRS. Here, we used 2-[18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) to provide the first head-to-head comparative analysis of cerebral glucose metabolism in TRS patients compared to schizophrenia responder patients (nTRS), and controls. Additionally, we investigated, for the first time, the differences between clozapine responders (Clz-R) and non-responders (Clz-nR).

STUDY DESIGN

53 participants underwent FDG-PET studies (41 patients and 12 controls). Response to conventional antipsychotics and to clozapine was evaluated using a standardized prospective procedure based on PANSS score changes. Maps of relative brain glucose metabolism were processed for voxel-based analysis using Statistical Parametric Mapping software.

STUDY RESULTS

Restricted areas of significant bilateral relative hypometabolism in the superior frontal gyrus characterized TRS compared to nTRS. Moreover, reduced parietal and frontal metabolism was associated with high PANSS disorganization factor scores in TRS (P < .001 voxel level uncorrected, P < .05 cluster level FWE-corrected). Only TRS compared to controls showed significant bilateral prefrontal relative hypometabolism, more extensive in CLZ-nR than in CLZ-R (P < .05 voxel level FWE-corrected). Relative significant hypermetabolism was observed in the temporo-occipital regions in TRS compared to nTRS and controls.

CONCLUSIONS

These data indicate that, in TRS patients, altered metabolism involved discrete brain regions not found affected in nTRS, possibly indicating a more severe disrupted functional brain network associated with disorganization symptoms.

Lurasidone Augmentation of Clozapine in Schizophrenia—Retrospective Chart Review

The aim of our study was to evaluate the effectiveness of lurasidone augmentation of clozapine in treatment-resistant schizophrenia (SZ) in a retrospective chart review. From the medical records of 916 SZ patients, we identified 16 individuals treated with a combination of clozapine and lurasidone. The detailed clinical data are described separately for each patient. We compared the Clinical Global Impression—Severity (CGI-S) scores between three points of observation: before the treatment and one month and two months after its initiation. CGI Improvement (CGI-I) scores were used to evaluate the treatment response between the first and last points of observation. The vast majority of patients (14/16, 87.5%) responded to lurasidone augmentation of clozapine (CGI-I scores 1 or 2). Therapeutic effects were observable after 3–12 weeks of treatment (median 6 (4–6)). A reduction in CGI-S scores was observed after the first month of observation. There was an observable reduction in positive, depressive and anxiety symptoms, as well as an improvement in psychosocial functioning. Two patients discontinued treatment due to side effects. Our study suggests that lurasidone augmentation of clozapine may lead to improvements in a broad range of SZ symptom dimensions.

Genomic Stratification of Clozapine Prescription Patterns Using Schizophrenia Polygenic Scores

BACKGROUND

Treatment-resistant schizophrenia affects approximately 30% of individuals with the disorder. Clozapine is the medication of choice in treatment-resistant schizophrenia, but optimizing administration and dose titration is complex. The identification of factors influencing clozapine prescription and response, including genetics, is of interest in a precision psychiatry framework.

METHODS

We used linear regression models accounting for demographic, pharmacological, and clinical covariates to determine whether a polygenic risk score (PRS) for schizophrenia would be associated with the highest dose recorded during clozapine treatment. Analyses were performed across 2 independent multiancestry samples of individuals from a UK patient monitoring system, CLOZUK2 (n = 3133) and CLOZUK3 (n = 909), and a European sample from a Norwegian therapeutic drug monitoring service (n = 417). In a secondary analysis merging both UK cohorts, logistic regression models were used to estimate the relationship between schizophrenia PRSs and clozapine doses classified as low, standard, or high.

RESULTS

After controlling for relevant covariates, the schizophrenia PRS was correlated with the highest clozapine dose on record for each individual across all samples: CLOZUK2 (β = 12.22, SE = 3.78, p = .001), CLOZUK3 (β = 12.73, SE = 5.99, p = .034), and the Norwegian cohort (β = 46.45, SE = 18.83, p = .014). In a secondary analysis, the schizophrenia PRS was associated with taking clozapine doses >600 mg/day (odds ratio = 1.279, p = .006).

CONCLUSIONS

The schizophrenia PRS was associated with the highest clozapine dose prescribed for an individual in records from 3 independent samples, suggesting that the genetic liability for schizophrenia might index factors associated with therapeutic decisions in cohorts of patients with treatment-resistant schizophrenia.

What Role for Long-Acting Injectable Antipsychotics in Managing Schizophrenia Spectrum Disorders in Children and Adolescents? A Systematic Review

BACKGROUND

Long-acting injectable antipsychotics (LAIAs) are an efficacious and well-tolerated treatment in adults with schizophrenia spectrum disorders (SSD). However, there is less evidence for their use in children and adolescents.

OBJECTIVES

The aim of this systematic review was to summarize findings regarding the effectiveness and side effects of LAIA in children and adolescents with SSD.

METHODS

Four databases (Web of Science, PubMed, MEDES, and Dialnet) were systematically searched for articles published between inception and 12 March, 2022, with the following inclusion criteria: (1) original articles or case reports; (2) providing data on efficacy/effectiveness or safety/tolerability of LAIA treatment in children and adolescents diagnosed with SSD (schizophrenia, schizoaffective disorder, schizophreniform disorder, non-affective psychotic disorder); (3) mean age of samples ≤ 18 years; and (4) written in English or Spanish. Exclusion criteria were review articles, clinical guides, expert consensus as well as posters or oral communication in conferences. The risk of bias was assessed using the ROBIS tool.

RESULTS

From 847 articles found, 13 met the inclusion criteria. These included seven single case reports or case series, four retrospective chart reviews, a 24-week open-label trial, and one observational prospective study, covering a total of 119 adolescents (aged 12-17 years) with SSD. Almost all the articles described data on second-generation LAIA (53 patients on risperidone [once every other week], 33 on paliperidone palmitate [once monthly], 10 on aripiprazole [once monthly], and two on olanzapine pamoate [once monthly]). Twenty-one patients were reported to be only on first-generation LAIAs. Non-adherence was the main reason for starting an LAIA. In all of the studies, the use of LAIAs was associated with improvement in the patients' symptoms.

CONCLUSIONS

There are few studies assessing the use of LAIAs in adolescents with SSD. Overall, these treatments have suggested good effectiveness and acceptable safety and tolerability. However, we found no studies examining their use in children aged < 12 years. The problems and benefits linked to this type of antipsychotic formulation in the child and adolescent population require further study, ideally with prospective, controlled designs.

Combination of Long-Acting Injectable Antipsychotics in the Treatment of Psychiatric Disorders-A Systematic Review of the Literature and Case Series

BACKGROUND

The treatment of refractory schizophrenia is complex, and compliance with oral treatment, including clozapine, can be challenging at times. The purpose of this case series and literature review article is to evaluate the efficacy of the combined use of 2 different long-acting injectable antipsychotics (LAIAs) on the number of psychiatric hospitalizations and emergency department visits. There are currently few data to support this treatment option, despite the frequent use of combinations of oral antipsychotics.

METHODS

We extracted the data from 8 different patients who received combination LAIAs from 1 hospital setting. We evaluated the frequency of hospitalization and emergency department visits before and after treatment with a mirror-image study design. A systematic review of existing literature was included to find all previously reported cases of combination LAIAs.

RESULTS

The frequency of hospitalizations was greatly reduced after the initiation of combination LAIA treatment in the majority of the cases at study site, as well as in the literature review. The number of ED visits was not as clearly affected. In the literature review, combinations of 2 LAIAs with different mechanisms of action were often documented. Symptom scores were also reduced in most reviewed cases.

CONCLUSIONS

Combinations of LAIAs seem to be promising as a treatment option for refractory psychotic disorders. This combination could be a treatment option for patients with limited alternatives, such as clozapine resistant or not eligible. The higher risk of adverse effects and long-term risks are not well documented.

Clozapine research from India: A systematic review

BACKGROUND

Although clozapine is much researched in western literature, a review on Indian research on clozapine published in 2010 reported limited data and need for further research in this area.

AIM

We aimed to conduct a systematic review of research on clozapine from India from 2010 to mid-2022 and also compare the same with research output before 2010.

METHODOLOGY

A systematic various search engines, i.e., PUBMED, Medknow, Hinari and Google Scholar was done using the key words clozapine and India. Published articles with clozapine in the title and having an author from India, published during 2010 to July 2022 were included.

RESULTS

Initial Internet and hand searches yielded 280 articles, out of which 126 articles were excluded due to various reasons and 154 articles, were included for the review. This included 84 case reports, 49 original articles, 11 review articles and 10 letters to the editor as comments. We found an increase in the number of publications during the period of 2010-2022 compared to 1997-2009 in all types of publications. Over the years a significant proportion of the articles focused on various side effects of clozapine, factors associated with response and non-response to clozapine and evaluation of outcomes other than efficacy/effectiveness. However, all the studies were limited to a single centre with no multicentric studies on clozapine.

CONCLUSION

Over the last 12 years or so, there is increase in the number of publications on clozapine. However, there is lack of multicentric studies.

Difference between treatment-resistant schizophrenia and clozapine-resistant schizophrenia

We read the impressive review article “Clozapine resistant schizophrenia: Newer avenues of management” with great enthusiasm and appreciation. The author believes that preventing clozapine resistance from developing may be the most effective treatment strategy for patients with clozapine-resistant schizophrenia (CRS), and optimizing clozapine treatment is a key component. Disentangling the differences between treatment-resistant schizophrenia and CRS is important for studies addressing treatment strategies for these difficult-to-treat populations.

A case report of clozapine-treatment-resistant schizophrenia successfully managed with brexpiprazole combination therapy

Clozapine-resistant schizophrenia (CRS) occurs in 40%- 70% of clozapine-treated schizophrenic patients. Hereby we describe a 20-year-old CRS subject with comorbid cannabinoid use disorder, successfully treated with clozapine-brexpiprazole combination, subsequently switched to clozapine plus long-acting injectable aripiprazole.

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.

Management of sedation due to clozapine

Sedation is one of the most common adverse effects of clozapine. Although tolerance develops to some extent, a significant proportion of patients continue to experience sedation and associated negative consequences on their quality of life. Sedation is also one of the most common reasons for the discontinuation of clozapine and it is therefore important to proactively manage it. This article provides brief guidance for clinicians.

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.