Beneficial Effects of Concomitant Long-Acting Injectable Antipsychotics on Time to Rehospitalization in Patients With Treatment-Resistant Schizophrenia Receiving Clozapine: A Retrospective Cohort Study.

Introduction: This study aimed to assess the association between long-acting injectable (LAI) antipsychotic prescription and the risk of psychiatric hospitalization in patients with treatment-resistant schizophrenia (TRS) receiving clozapine.Methods: In this retrospective cohort study at a single tertiary psychiatric center, we analyzed rehospitalization hazard ratios (HRs) in refractory schizophrenia patients, classified by DSM-IV-TR and DSM-5 criteria. We examined various psychotropic regimens-clozapine with or without other oral antipsychotics (OAPs) or LAI antipsychotics. Subgroups were stratified by daily clozapine dosage and previous admissions.Results: A total of 719 patients were included in the study. Analyses were conducted on all the patients over 3- month, 6-month, and 1-year periods. Patients treated with a combination of clozapine and LAI antipsychotics (CLO + LAI) had a significantly higher number of previous hospitalizations (P = .003), and a higher daily dose of clozapine (P < .001) was found in the CLO + OAP group than in the CLO (monotherapy) group and the CLO + LAI group. Patients treated with LAI antipsychotic comedication had significantly lower HRs for rehospitalization in 1 year among 3 studied groups. Moreover, the protective effects of LAI antipsychotics were observed in all the subgroups stratified by daily clozapine dosage and number of previous admissions to represent disease severity.Conclusion: The combination of clozapine and LAI antipsychotics was associated with a significantly lower risk of rehospitalization compared to both the combination of clozapine and OAPs and clozapine monotherapy. The use of LAI antipsychotics should be considered to prevent rehospitalization in patients with TRS who are already being treated with clozapine.

Rapid Metabolism Underlying Subtherapeutic Serum Levels of Atypical Antipsychotics Preceding Clozapine Treatment: A Retrospective Analysis of Real-World Data.

INTRODUCTION: Adequate antipsychotic treatment intensity is required before diagnosing resistant schizophrenia and initiating clozapine treatment. We aimed to investigate potential rapid drug metabolism underlying low dose-adjusted serum concentration (CD) of non-clozapine atypical antipsychotics preceding clozapine treatment. METHODS: Patients using non-clozapine, atypical antipsychotics (aripiprazole, risperidone, olanzapine, or quetiapine) within 1 year before starting clozapine were included in this study from a therapeutic drug monitoring service in Oslo, Norway, between 2005 and 2023. Patients were assigned into low CD (LCD) and normal CD (NCD) subgroups. Using a reference sample with 147,964 antipsychotic measurements, LCD was defined as CDs below the 25th percentile, while patients with NCD exhibited CDs between the 25th and 75th percentile of the respective reference measurements. Metabolic ratios, doses, and frequency of subtherapeutic levels of non-clozapine antipsychotics were compared between LCD and NCD groups. RESULTS: Preceding clozapine treatment, 110 out of 272 included patients (40.4%) were identified with LCD. Compared with the NCD group, LCD patients exhibited higher metabolic ratios of olanzapine (1.5-fold; p < 0.001), quetiapine (3.0-fold; p < 0.001), and risperidone (6.0-fold; p < 0.001). Metabolic ratio differences were independent of smoking and CYP2D6 genotype for olanzapine (p = 0.008) and risperidone (p = 0.016), respectively. Despite higher doses of olanzapine (1.25-fold; p = 0.054) and quetiapine (1.6-fold; p = 0.001) in LCD versus NCD patients, faster metabolism among the former was accompanied by higher frequencies of subtherapeutic levels of olanzapine (3.3-fold; p = 0.044) and quetiapine (1.8-fold; p = 0.005). CONCLUSION: LCD and associated rapid metabolism of non-clozapine antipsychotics is frequent before starting clozapine treatment. For olanzapine and quetiapine, this is associated with significantly increased risk of having subtherapeutic concentrations.

The role of psychosis and clozapine load in excessive checking in treatment-resistant schizophrenia: longitudinal observational study.

BACKGROUND: A significant proportion of people with clozapine-treated schizophrenia develop 'checking' compulsions, a phenomenon yet to be understood. AIMS: To use habit formation models developed in cognitive neuroscience to investigate the dynamic interplay between psychosis, clozapine dose and obsessive-compulsive symptoms (OCS). METHOD: Using the anonymised electronic records of a cohort of clozapine-treated patients, including longitudinal assessments of OCS and psychosis, we performed longitudinal multi-level mediation and multi-level moderation analyses to explore associations of psychosis with obsessiveness and excessive checking. Classic bivariate correlation tests were used to assess clozapine load and checking compulsions. The influence of specific genetic variants was tested in a subsample. RESULTS: A total of 196 clozapine-treated individuals and 459 face-to-face assessments were included. We found significant OCS to be common (37.9%), with checking being the most prevalent symptom. In mediation models, psychosis severity mediated checking behaviour indirectly by inducing obsessions (r = 0.07, 95% CI 0.04-0.09; P < 0.001). No direct effect of psychosis on checking was identified (r = -0.28, 95% CI -0.09 to 0.03; P = 0.340). After psychosis remission (n = 65), checking compulsions correlated with both clozapine plasma levels (r = 0.35; P = 0.004) and dose (r = 0.38; P = 0.002). None of the glutamatergic and serotonergic genetic variants were found to moderate the effect of psychosis on obsession and compulsion (SLC6A4, SLC1A1 and HTR2C) survived the multiple comparisons correction. CONCLUSIONS: We elucidated different phases of the complex interplay of psychosis and compulsions, which may inform clinicians' therapeutic decisions.

Multiple serum anti-glutamate receptor antibody levels in clozapine-treated/naïve patients with treatment-resistant schizophrenia.

BACKGROUND: Glutamatergic function abnormalities have been implicated in the etiology of treatment-resistant schizophrenia (TRS), and the efficacy of clozapine may be attributed to its impact on the glutamate system. Recently, evidence has emerged suggesting the involvement of immune processes and increased prevalence of antineuronal antibodies in TRS. This current study aimed to investigate the levels of multiple anti-glutamate receptor antibodies in TRS and explore the effects of clozapine on these antibody levels. METHODS: Enzyme linked immunosorbent assay (ELISA) was used to measure and compare the levels of anti-glutamate receptor antibodies (NMDAR, AMPAR, mGlur3, mGluR5) in clozapine-treated TRS patients (TRS-C, n = 37), clozapine-naïve TRS patients (TRS-NC, n = 39), and non-TRS patients (nTRS, n = 35). Clinical symptom severity was assessed using the Positive and Negative Symptom Scale (PANSS), while cognitive function was evaluated using the MATRICS Consensus Cognitive Battery (MCCB). RESULT: The levels of all four glutamate receptor antibodies in TRS-NC were significantly higher than those in nTRS (p < 0.001) and in TRS-C (p < 0.001), and the antibody levels in TRS-C were comparable to those in nTRS. However, no significant associations were observed between antibody levels and symptom severity or cognitive function across all three groups after FDR correction. CONCLUSION: Our findings suggest that TRS may related to increased anti-glutamate receptor antibody levels and provide further evidence that glutamatergic dysfunction and immune processes may contribute to the pathogenesis of TRS. The impact of clozapine on anti-glutamate receptor antibody levels may be a pharmacological mechanism underlying its therapeutic effects.

Navigated and individual α-peak-frequency-guided transcranial magnetic stimulation in male patients with treatment-refractory schizophrenia.

BACKGROUND: Previous electroencephalography (EEG) studies have indicated altered brain oscillatory α-band activity in schizophrenia, and treatment with repetitive transcranial magnetic stimulation (rTMS) using individualized α-frequency has shown therapeutic effects. Magnetic resonance imaging-based neuronavigation methods allow stimulation of a specific cortical region and improve targeting of rTMS; therefore, we sought to study the efficacy of navigated, individual α-peak-frequency-guided rTMS (αTMS) on treatment-refractory schizophrenia. METHODS: We recruited medication-refractory male patients with schizophrenia or schizoaffective disorder in this doubleblind, sham-controlled study. We randomized patients to a 3-week course of either active αTMS or sham stimulation applied to the left dorsolateral prefrontal cortex (DLPFC). We assessed participants with the Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impression Scale (CGI) at baseline and after treatment. We conducted a follow-up assessment with the PANSS 3 months after intervention. RESULTS: We included 44 patients. After treatment, we observed a significantly higher PANSS total score (p = 0.029), PANSS general psychopathology score (p = 0.027) and PANSS 5-factor model cognitive-disorganized factor score (p = 0.011) in the αTMS group than the sham group. In addition, the CGI-Improvement score was significantly higher among those who received αTMS compared with sham stimulation (p = 0.048). LIMITATIONS: The limited number of study participants included only male patients. Depression was not formally evaluated. CONCLUSION: Navigated αTMS to the left DLPFC reduced total, general psychopathological, and cognitive-disorganized symptoms of schizophrenia. These results provide evidence for the therapeutic efficacy of individual α-peak-frequency-guided rTMS in treatment-refractory schizophrenia. CLINICAL TRIAL REGISTRATION: NCT01941251; ClinicalTrials.gov.

Palliative psychiatry for a patient with treatment-refractory schizophrenia and severe chronic malignant catatonia: case report.

BACKGROUND: Palliative psychiatry is an emerging field that suggests a role for palliative interventions in the management of severe and persistent mental illness (SPMI). Current literature describes using a palliative approach for patients with severe anorexia nervosa. To our knowledge, this is the first case report describing end-of-life care in a patient with treatment-refractory catatonic schizophrenia. CASE DESCRIPTION: We describe the case of a 49-year-old man with schizophrenia and severe chronic agitated/malignant catatonia who was hospitalized for ten months. Multiple treatment trials including medication such as neuroleptics and benzodiazepines, electroconvulsive therapy, and empiric interventions such as intravenous immunoglobulins were either not tolerated or did not result in clinically significant improvement. The patient continued to intermittently require intubation and sedation to control intractable behavioral and psychiatric disturbances. Ultimately, with collaboration of psychiatry, neurology, ethics, intensive care, and palliative care teams, the patient's parents decided to forgo further diagnostic testing and life-sustaining treatments. The patient died weeks later of aspiration pneumonia with good symptom control. CONCLUSIONS: This case permits discussion of palliative interventions in patients with SPMI such as treatment-refractory psychotic disorders who likely cannot achieve a quality of life that is acceptable to them. Here, it can be justified to prioritize relief of suffering and prevention of further burdensome interventions over treatment of the SPMI symptoms such as catatonia and even over keeping the patient alive.

Successful Clozapine Rechallenge After Clozapine-Induced Severe Anemia: A Case Report.

INTRODUCTION: Clozapine, a second-generation antipsychotic (SGA), is considered the gold standard medication to treat patients with treatment-resistant schizophrenia (TRS). Despite its efficacy, clozapine is associated with adverse effects, notably neutropenia and agranulocytosis. Other hematological adverse effects are less common. Severe anemia is a rare adverse effect seldom reported in the literature and is typically associated with pure red cell aplasia (PRCA). Nevertheless, the benefits of clozapine in managing TRS make rechallenge a reasonable option. CASE REPORT: We present the case of a 35-year-old man with TRS, resistant to previous antipsychotics, who experienced severe anemia during clozapine treatment. An investigation for clozapine-induced anemia revealed PRCA on myelogram. After discontinuing clozapine, the patient's hemoglobin levels recovered. Subsequent treatments with olanzapine, zuclopenthixol, and aripiprazole proved ineffective, leading us to consider a clozapine rechallenge. The rechallenge, monitored for 58 days, resulted in improved psychiatric symptoms and stable hemoglobin levels. The patient remained stable during 6 months of follow-up, with no hematological changes. DISCUSSION: PRCA is a very rare adverse effect of clozapine. The cause of drug-induced PRCA is still unknown; for clozapine, there are no studies. Rechallenge after a severe and rare adverse effect is a complex decision. This case is the first to report a successful clozapine rechallenge following severe anemia without other blood dyscrasias, emphasizing the imperative need for close monitoring during the rechallenge process. Further study is warranted to understand the predictive factors for a successful outcome in clozapine rechallenges.

[Management of treatment resistance-Treatment-resistant schizophrenia]. / Management von Therapieresistenzen ­ therapieresistente Schizophrenie.

Despite a very high prevalence and substantial impairments among affected individuals, treatment-resistant schizophrenia (TRS) has not been sufficiently researched in clinical research in the field of psychiatric disorders and the pathophysiology is still poorly understood. A better clinical and pathophysiological understanding of this heterogeneous and severely affected population of people with persistent symptoms in different domains is necessary in order not only to be able to intervene early but also to develop novel therapeutic strategies or individualized treatment approaches. This review article presents the state of the art criteria of the pharmacological TRS, neurobiological disease models and predictive factors for TRS as well as the phenomenon of pseudo-treatment resistance and the clinical management of TRS. In the future, not only the use of operationalized criteria and definitions of TRS in longitudinal studies and randomized-controlled trials (RCTs) are paramount, but also the observation of trajectories with the integration of multimodal longitudinal phenotyping and the longitudinal collection of clinical routine data in academic research, which will be possible in the newly created German Center for Mental Health (DZPG).

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.

CLEAR - clozapine in early psychosis: study protocol for a multi-centre, randomised controlled trial of clozapine vs other antipsychotics for young people with treatment resistant schizophrenia in real world settings.

BACKGROUND: Clozapine is an antipsychotic drug with unique efficacy, and it is the only recommended treatment for treatment-resistant schizophrenia (TRS: failure to respond to at least two different antipsychotics). However, clozapine is also associated with a range of adverse effects which restrict its use, including blood dyscrasias, for which haematological monitoring is required. As treatment resistance is recognised earlier in the illness, the question of whether clozapine should be prescribed in children and young people is increasingly important. However, most research to date has been in older, chronic patients, and evidence regarding the efficacy and safety of clozapine in people under age 25 is lacking. The CLEAR (CLozapine in EARly psychosis) trial will assess whether clozapine is more effective than treatment as usual (TAU), at the level of clinical symptoms, patient rated outcomes, quality of life and cost-effectiveness in people below 25 years of age. Additionally, a nested biomarker study will investigate the mechanisms of action of clozapine compared to TAU. METHODS AND DESIGN: This is the protocol of a multi-centre, open label, blind-rated, randomised controlled effectiveness trial of clozapine vs TAU (any other oral antipsychotic monotherapy licenced in the British National Formulary) for 12 weeks in 260 children and young people with TRS (12-24 years old). AIM AND OBJECTIVES: The primary outcome is the change in blind-rated Positive and Negative Syndrome Scale scores at 12 weeks from baseline. Secondary outcomes include blind-rated Clinical Global Impression, patient-rated outcomes, quality of life, adverse effects, and treatment adherence. Patients will be followed up for 12 months and will be invited to give consent for longer term follow-up using clinical records and potential re-contact for further research. For mechanism of action, change in brain magnetic resonance imaging (MRI) biomarkers and peripheral inflammatory markers will be measured over 12 weeks. DISCUSSION: The CLEAR trial will contribute knowledge on clozapine effectiveness, safety and cost-effectiveness compared to standard antipsychotics in young people with TRS, and the results may guide future clinical treatment recommendation for early psychosis. TRIAL REGISTRATION: ISRCTN Number: 37176025, IRAS Number: 1004947. TRIAL STATUS: In set-up. Protocol version 4.0 01/08/23. Current up to date protocol available here: https://fundingawards.nihr.ac.uk/award/NIHR131175# /.

Potential impact on mental health in patients with treatment-resistant schizophrenia - clozapine augmentation with long-acting parenteral antipsychotics: a case series.

INTRODUCTION: The rate of pharmacoresistance among in patients diagnosed with schizophrenia is around 30%. Clozapineis the drug of choice for these patients; however, an adequate response to treatment doesn't always occur. One of the possible augmentation approaches, specifically for non-adherent patients, is the administration of long-acting parenteral antipsychotics. Our goal was to evaluate previous experiences of administering a combination of the atypical antipsychotic clozapine and long-acting injectable antipsychotics to pharmacoresistant patients at the Department of Psychiatry the Czech Republic and to assess the safety and effectiveness of such administration. METHODS: A retrospective evaluation of patient case studies was conducted for those who were hospitalized in the Ward for the therapy of Psychotic disorders between 2016 and 2020 and had a medication history of combining clozapine and depot antipsychotics. RESULTS: Over half of the patients had no illness relapses during the observed period. The clinical manifestation of adverse effects from combination therapy appears low in our patient sample, primarily involving mild and pharmacologically manageable side effects (tachycardia). Only one of the cases recorded neutropenia, which led to discontinuation of clozapine; the patient was maintained on long-acting injectable antipsychotics medication. CONCLUSION: From our findings, it can be inferred that augmenting clozapine with depot antipsychotics is a potential therapeutic intervention that pharmacoresistant patients could benefit from. However, it is essential to emphasize that this therapeutic approach should only be administered after carefully considering the patient's existing treatment. It should be strictly individualized based on the treating physician's or clinical pharmacist's sufficient professional experience.

Virtual twins for model-informed precision dosing of clozapine in patients with treatment-resistant schizophrenia.

Model-informed precision dosing using virtual twins (MIPD-VTs) is an emerging strategy to predict target drug concentrations in clinical practice. Using a high virtualization MIPD-VT approach (Simcyp version 21), we predicted the steady-state clozapine concentration and clozapine dosage range to achieve a target concentration of 350 to 600 ng/mL in hospitalized patients with treatment-resistant schizophrenia (N = 11). We confirmed that high virtualization MIPD-VT can reasonably predict clozapine concentrations in individual patients with a coefficient of determination (R2 ) ranging between 0.29 and 0.60. Importantly, our approach predicted the final dosage range to achieve the desired target clozapine concentrations in 73% of patients. In two thirds of patients treated with fluvoxamine augmentation, steady-state clozapine concentrations were overpredicted two to four-fold. This work supports the application of a high virtualization MIPD-VT approach to inform the titration of clozapine doses in clinical practice. However, refinement is required to improve the prediction of pharmacokinetic drug-drug interactions, particularly with fluvoxamine augmentation.

Gene expression imputation provides clinical and biological insights into treatment-resistant schizophrenia polygenic risk.

Genome-wide association studies (GWAS) have revealed the polygenic nature of treatment-resistant schizophrenia TRS. Gene expression imputation allowed the translation of GWAS results into regulatory mechanisms and the construction of gene expression (GReX) risk scores (GReX-RS).  In the present study we computed GReX-RS from the largest GWAS of TRS to assess its association with clinical features. We perform transcriptome imputation in the largest GWAS of TRS to find GReX associated with TRS using brain tissues. Then, for each tissue, we constructed a GReX-RS of the identified genes in a sample of 254 genotyped first episode of psychosis (FEP) patients to test its association with clinical phenotypes, including clinical symptomatology, global functioning and cognitive performance. Our analysis provides evidence that the polygenic basis of TRS includes genetic variants that modulate the expression of certain genes in certain brain areas (substantia nigra, hippocampus, amygdala and frontal cortex), which at the same time are related to clinical features in FEP patients, mainly persistence of negative symptoms and cognitive alterations in sustained attention, which have also been suggested as clinical predictors of TRS. Our results provide a clinical explanation of the polygenic architecture of TRS and give more insight into the biological mechanisms underlying TRS.

Real-World Effectiveness of High-Dose Olanzapine and Clozapine for Treatment-Resistant Schizophrenia in Japan: A Retrospective Bidirectional Mirror-Image Study.

BACKGROUND: Clozapine is considered the gold standard medication for treatment-resistant schizophrenia (TRS). However, given that clozapine treatment is associated with the burden of regular blood monitoring and the risk of life-threatening adverse effects, high-dose olanzapine can serve as an alternative treatment. We conducted a bidirectional mirror-image study to evaluate the effectiveness of high-dose olanzapine compared with clozapine. METHODS: We included patients with TRS who switched from olanzapine to clozapine or switched from clozapine to olanzapine, and received high-dose (>20 mg/d) olanzapine treatment for ≥4 weeks at Yamanashi Prefectural Kita Hospital. We obtained data on hospitalization, seclusion, and modified electroconvulsive therapy (mECT) during the clozapine phase and the olanzapine phase. RESULTS: A total of 44 patients were included. When patients switched from high-dose olanzapine to clozapine (n = 32), significant reductions were found in the total days of seclusion, the total number of mECT, and the number of patients who received mECT at least once. When patients switched from clozapine to high-dose olanzapine (n = 12), a significant reduction was found in the number of patients who received mECT at least once. When data from both directions of treatment were combined, significant reductions were found in the total days of seclusion, the total number of mECT, and the number of patients who received mECT at least once in favor of clozapine. CONCLUSIONS: Findings suggest that high-dose olanzapine may not be as effective as clozapine for patients with TRS in real-world practice. However, it should be noted that there are unique circumstances that restrict the use of clozapine in Japan.