Practitioner attitudes to clozapine initiation

Current perspectives on the recognition and management of treatment-resistant schizophrenia: challenges and opportunities

INTRODUCTION

Treatment-resistant schizophrenia (TRS) significantly impacts patients with schizophrenia, leading to a high disease burden, reduced quality of life, and functional impairment. Many patients fail to respond to standard antipsychotic treatments, requiring specialized therapeutic approaches. Clozapine remains the only approved treatment for patients with TRS, demonstrating effectiveness in reducing symptoms, hospitalizations, and risk of suicide. However, its use is often delayed due to concerns about adverse events, and the need for ongoing monitoring.

AREAS COVERED

This critical perspective incorporates insights from psychiatrists in Greece and a comprehensive literature analysis that includes clinical guidelines and systematic reviews. It highlights strategies for early diagnosis and timely initiation of clozapine, while emphasizing practical challenges in its use. Recommendations emphasize reducing treatment delays and overcoming barriers such as inadequate training and hesitancy among clinicians. A comprehensive literature search was conducted on PubMed, Google Scholar, and Cochrane Library without any date restrictions to ensure a thorough review of available evidence. The initial literature search was carried out in September 2024, with a subsequent search conducted in March 2025.

EXPERT OPINION

International guidelines consistently recommend clozapine as the first-line treatment for patients with TRS; nevertheless, the authors advocate enhanced awareness to optimize use. Most adverse events can be effectively managed with proper oversight, and early initiation is crucial to improving remission rates and the quality of life of patients with TRS. There is a need for systemic improvements in clinical practice, which requires evidence-based guidance to better address treatment efficacy in this challenging patient population.

What is the current scope of research assessing patients' and clinicians' perspectives on clozapine treatment? A comprehensive scoping review

OBJECTIVES

Clozapine is continuously underused. The existing systematic reviews addressing barriers to clozapine prescribing primarily focus on clinical staff's attitudes and perceived barriers to prescribing. However, a preliminary literature search revealed additional literature on the subject not previously included in systematic reviews, including literature on patient perspectives. A scoping review is warranted to map the scope of primary studies on patients' and/or clinicians' perspectives on clozapine treatment and to identify gaps in research.

DESIGN

A scoping review was designed and reported in accordance with established guidelines for scoping reviews.

DATA SOURCES

The electronic databases Cochrane Library, CINAHL, Web of Science, PsycINFO, MEDLINE, EMBASE, Google Scholar and two grey literature databases were searched. Furthermore, citation tracking of selected studies was undertaken.

ELIGIBILITY CRITERIA

We included primary, empirical studies reporting clinicians' and/or patients' perspectives on clozapine treatment. No limitation was set for the year of publication or type of primary study.

DATA EXTRACTION AND SYNTHESIS

Two researchers independently screened for studies, extracted the data and coded the content. Findings were summarised visually and narratively.

RESULTS

146 studies were included. Most studies reported on patients' or clinicians' perspectives on active clozapine treatment or on clinicians' perspectives on barriers to clozapine initiation in general. Three gaps in research were identified: (1) clozapine-eligible, yet clozapine-naïve, patients' attitudes towards clozapine commencement, (2) clinicians' reasons for clozapine withholding and perceived facilitators of clozapine treatment in specific patient-cases and (3) patient and clinician perspectives on clozapine discontinuation, continuation and rechallenge in specific patient cases.

CONCLUSIONS

Research on clozapine perspectives tends to repeat itself. Future studies addressing the identified gaps in evidence could provide the insights needed to optimise clozapine utilisation.

Psychiatrists' views on clozapine prescribing in Ireland

INTRODUCTION

Despite proven effectiveness in refractory schizophrenia, clozapine remains underutilised, and it is important to understand potential reasons for this. This study's aim was to examine in a National sample of Consultant Psychiatrists their knowledge of, attitudes and perceived barriers to clozapine use.

METHODS

A novel questionnaire was designed and distributed by email to 275 Consultant Psychiatrists in Republic of Ireland.

RESULTS

Twenty-eight percent (n = 77) completed the survey, with 55% of respondents practicing for 15 or more years. Clinicians expressed confidence in managing clozapine treatment and side effects and were well aware of clozapine's clinical effectiveness and guideline-based use. A majority indicated insufficient experience managing rechallenge and half expressed insufficient experience managing adverse events. Perceived patient factors were highlighted as barriers with 69% of respondents reporting patients' concern about effectiveness and 50% regarding tolerability. Sixty-four percent (n = 40) indicated that a specialised/tertiary clozapine service would facilitate initiation, with 57% (n = 36) reporting less frequent blood monitoring would aid clozapine prescribing. A majority identified that access to dedicated staff (81%, n = 51) and dedicated day hospital services (84%, n = 53) would facilitate community initiation.

CONCLUSION

Consultants are familiar with clozapine use and related guidelines. Dedicated staff and facilities for clozapine use is one identified structural change to enhance clozapine prescribing in Ireland. Tertiary service or clinical advice service would assist in clozapine rechallenge cases or in managing significant adverse events. More structured patient education regarding clozapine effectiveness and professional development programmes focused on managing side effects and rechallenge may promote clozapine use.

Eight-month intensive meditation-based intervention improves refractory hallucinations and delusions and quality of life in male inpatients with schizophrenia: a randomized controlled trial

AIM

This study investigated the impact of an 8-month daily-guided intensive meditation-based intervention (iMI) on persistent hallucinations/delusions and health-related quality of life (QoL) in male inpatients with schizophrenia with treatment-refractory hallucinations and delusions (TRHDs).

METHODS

A randomized controlled trial assigned 64 male inpatients with schizophrenia and TRHD equally to an 8-month iMI plus general rehabilitation program (GRP) or GRP alone. Assessments were conducted at baseline and the third and eighth months using the Positive and Negative Syndrome Scale (PANSS), 36-Item Short Form-36 (SF-36), and Five Facet Mindfulness Questionnaire (FFMQ). Primary outcomes measured PANSS reduction rates for total score, positive symptoms, and hallucinations/delusions items. Secondary outcomes assessed PANSS, SF-36, and FFMQ scores for psychotic symptoms, health-related QoL, and mindfulness skills, respectively.

RESULTS

In the primary outcome, iMI significantly improved the reduction rates of PANSS total score, positive symptoms, and hallucination/delusion items compared with GRP at both the third and eighth months. Treatment response rates (≥25% reduction) for these measures significantly increased in the iMI group at the eighth month. Concerning secondary outcomes, iMI significantly reduced PANSS total score and hallucination/delusion items, while increasing scores in physical activity and mindfulness skills at both the third and eighth months compared with GRP. These effects were more pronounced with an 8-month intervention compared with a 3-month intervention.

CONCLUSIONS

An iMI benefits patients with TRHDs by reducing persistent hallucinations/delusions and enhancing health-related QoL. Longer iMI duration yields superior treatment outcomes.

A qualitative study of clinicians' perspectives on reasons for delays in clozapine initiation

OBJECTIVES

To elicit mental health clinicians' views on the reasons for delayed initiation of clozapine treatment.

METHOD

Thematic analysis of transcripts from a semi-structured interview of 15 mental health clinicians.

RESULTS

Four major themes emerged from data analysis: Patient and Carer Factors, Medication factors, Protocol factors, and Prescriber factors. Patient and carer anxiety over side effects and experience of stigma, difficulties in implementing the monitoring protocol, problems with community managing of treatment, prescriber preferences and practices, and gaps in mental health services were some of the reasons identified.

CONCLUSION

Education and support to patients and carers, a modified monitoring protocol, establishing clozapine clinics, improved early intervention services, and upskilling of clinicians can promote early clozapine initiation.

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# /.

Capillary blood sampling for the determination of clozapine concentrations: analytical validation and patient experience

Patients may be reluctant to start clozapine (CLZ) because of the frequent blood sampling needed for white blood cell monitoring, but also therapeutic drug monitoring of CLZ. Finger prick, instead of venepuncture, might lower the threshold to CLZ use. The aim of this study was to determine whether CLZ concentrations are the same in capillary and venous blood samples. Capillary blood was drawn by finger prick and collected in the Hem-Col tube. Paired capillary and venous blood samples were collected from inpatients and outpatients of a mental health institute. Patients were asked to rate pain, experience, and preference for blood sampling method. Passing-Bablok analysis of 40 paired samples showed that CLZ concentrations were statistically equal in capillary and venous samples {slope 0.96 [95% confidence interval (CI): 0.88-1.04], intercept -6.86 (95% CI: -30.75 to 24.13)}. Venepuncture was the preferred method based on the experience ( P  = 0.009) and preference ( P  = 0.043) items. In conclusion, CLZ concentrations were similar in venous and capillary blood samples. Venepuncture appeared to be preferred to finger prick for blood sampling. Our results emphasize the importance of consulting patients' individual preference for blood sampling method.

Unraveling ethnic disparities in antipsychotic prescribing among patients with psychosis: A retrospective cohort study based on electronic clinical records

BACKGROUND

Previous studies have shown mixed evidence on ethnic disparities in antipsychotic prescribing among patients with psychosis in the UK, partly due to small sample sizes. This study aimed to examine the current state of antipsychotic prescription with respect to patient ethnicity among the entire population known to a large UK mental health trust with non-affective psychosis, adjusting for multiple potential risk factors.

METHODS

This retrospective cohort study included all patients (N = 19,291) who were aged 18 years or over at their first diagnoses of non-affective psychosis (identified with the ICD-10 codes of F20-F29) recorded in electronic health records (EHRs) at the South London and Maudsley NHS Trust until March 2021. The most recently recorded antipsychotic treatments and patient attributes were extracted from EHRs, including both structured fields and free-text fields processed using natural language processing applications. Multivariable logistic regression models were used to calculate the odds ratios (OR) for antipsychotic prescription according to patient ethnicity, adjusted for multiple potential contributing factors, including demographic (age and gender), clinical (diagnoses, duration of illness, service use and history of cannabis use), socioeconomic factors (level of deprivation and own-group ethnic density in the area of residence) and temporal changes in clinical guidelines (date of prescription).

RESULTS

The cohort consisted of 43.10 % White, 8.31 % Asian, 40.80 % Black, 2.64 % Mixed, and 5.14 % of patients from Other ethnicity. Among them, 92.62 % had recorded antipsychotic receipt, where 24.05 % for depot antipsychotics and 81.72 % for second-generation antipsychotic (SGA) medications. Most ethnic minority groups were not significantly different from White patients in receiving any antipsychotic. Among those receiving antipsychotic prescribing, Black patients were more likely to be prescribed depot (adjusted OR 1.29, 95 % confidence interval (CI) 1.14-1.47), but less likely to receive SGA (adjusted OR 0.85, 95 % CI 0.74-0.97), olanzapine (OR 0.82, 95 % CI 0.73-0.92) and clozapine (adjusted OR 0.71, 95 % CI 0.6-0.85) than White patients. All the ethnic minority groups were less likely to be prescribed olanzapine than the White group.

CONCLUSIONS

Black patients with psychosis had a distinct pattern in antipsychotic prescription, with less use of SGA, including olanzapine and clozapine, but more use of depot antipsychotics, even when adjusting for the effects of multiple demographic, clinical and socioeconomic factors. Further research is required to understand the sources of these ethnic disparities and eliminate care inequalities.

Outcome of COVID-19 mRNA Vaccination in Patients Treated With Clozapine WHO Previously Went Through SARS-COV-2 Infection

BACKGROUND

The outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic had multiple consequences for the health care system, especially for patients with mental illnesses. Schizophrenia patients particularly appear to have a higher risk of complications due to coronavirus-19 (COVID-19). Clozapine remains the gold standard for treatment-resistant schizophrenia (TRS). However, the COVID-19 pandemic had an important negative impact on clozapine treatment, mainly because of its administration protocol, which was very difficult to follow during the restrictions imposed in the pandemic, and its side effects in patients with COVID-19 infection. Vaccination is an effective method of avoiding SARS-CoV-2 infection or its severe complications, especially in susceptible populations. Data on adverse events after vaccination against COVID-19 are limited, both in the general population and in schizophrenia patients.

STUDY QUESTION

The study aimed to investigate the safety of COVID-19 vaccination in patients treated with clozapine for hematological parameters.

STUDY DESIGN

We conducted an analytical cross-sectional study between July 1, 2021, and June 30, 2022. We compared 2 groups of COVID-19 vaccinated patients who had previously experienced SARS-CoV-2 infection: The first group was treated with clozapine, whereas the second group was treated with other antipsychotics.

MEASURES AND OUTCOMES

The primary objective was to identify granulocytopenia, leukocytopenia, and lymphocytopenia. The results were measured after the second dose of the Pfizer-BioNTech vaccine.

RESULTS

This study included 100 patients. White blood cell count changes were limited to a few cases of mild granulocytopenia (8.16% in the clozapine group and 3.92% in the nonclozapine group, P = 0.37) with no cases of severe granulocytopenia or agranulocytosis.

CONCLUSIONS

As far as leukocyte counts are concerned, mRNA COVID-19 vaccination seems to be safe in patients treated with clozapine who previously had SARS-CoV-2 infection. Leukocyte changes had no clinical implications.

Dopamine supersensitivity psychosis and delay of clozapine treatment in patients with treatment-resistant schizophrenia

Both the underutilization of clozapine and treatment resistance of patients to clozapine are serious problems worldwide. Identifying clinical markers predicting response to clozapine would help clinicians more effectively utilize clozapine treatment. The present study retrospectively assessed dopamine supersensitivity psychosis (DSP) in addition to other measures such as age at disease onset and delay of clozapine introduction for a total of 47 treatment-resistant schizophrenia (TRS) patients. The response to clozapine was judged with CGI-C at 1 and 2 years from clozapine introduction. Results revealed that the DSP group tended to have a longer delay between designation of TRS and introduction of clozapine and continued to have slightly more severe psychopathology after treatment with clozapine, showing only slight improvement. The logistic regression analysis showed that the age at disease onset was the only significant indicator, predicting responsiveness to clozapine: patients with an onset age <20 years had a significantly better response to clozapine than patients with an onset age ≥20 years. The present study suggests that DSP might be related to a longer delay in clozapine introduction and the persistence of refractory symptoms despite clozapine treatment, whereas early age of disease onset might be related to a better response to clozapine.

Clozapine rechallenge or continuation despite neutropenia or agranulocytosis using colony-stimulating factor: A systematic review

OBJECTIVES

Rechallenge/continuation of clozapine in association with colony-stimulating factors (CSFs) following neutropenia/agranulocytosis has been reported, but many questions remain unanswered about efficacy and safety. This systematic review aims to assess the efficacy and safety of rechallenging/continuing clozapine in patients following neutropenia/agranulocytosis using CSFs.

METHODS

MEDLINE, Embase, PsycInfo, and Web of Science databases were searched from inception date to July 31, 2022. Articles screening and data extraction were realized independently by two reviewers, according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 systematic review guidance. Included articles had to report on at least one case where clozapine was rechallenged/continued using CSFs despite previous neutropenia/agranulocytosis.

RESULTS

Eight hundred forty articles were retrieved; 34 articles met the inclusion criteria, totaling 59 individual cases. Clozapine was successfully rechallenged/continued in 76% of patients for an average follow-up period of 1.9 years. There was a trend toward better efficacy reported in case reports/series, compared with consecutive case series (overall success rates of 84% and 60%, respectively, p-value = 0.065). Two administration strategies were identified, "as-needed" and prophylactic, both yielding similar success rates (81% and 80%, respectively). Only mild and transient adverse events were documented.

CONCLUSIONS

Although limited by the relatively small number of published cases, factors such as time of onset to first neutropenia and severity of the episode did not seem to impact the outcome of a subsequent clozapine rechallenge using CSFs. While the efficacy of this strategy remains to be further adequately evaluated in more rigorous study designs, its long-term innocuity warrants considering its use more proactively in the management of clozapine hematological adverse events as to maintain this treatment for as many individuals as possible.

De Novo Seizures, Obsessive Compulsive Symptoms and Neutropenias in Patients on Clozapine: A Retrospective Cohort Study

BACKGROUND

Clozapine has well-documented inter-ethnic variations in pharmacokinetics. There is a paucity of data about clozapine use and associated adverse events such as seizures, obsessive compulsive symptoms, neutropenia, and agranulocytosis, from India.

METHODS

This retrospective cohort study followed up 228 patients initiated on clozapine in a tertiary care referral center in India for an average of 10 years. We calculated incidence rates of new-onset seizures, new-onset obsessive compulsive symptoms, agranulocytosis, and neutropenia. We collected data on doses of clozapine used and serum assays and calculated concentration-to-dose (C/D) ratios. We also collected relevant clinical details about clozapine-induced seizures.

RESULTS

In the sample, 16.8% had new-onset seizures, 12.3% had new-onset OC symptoms, 2.7% had neutropenia, and 0.9% had agranulocytosis. The mean C/D ratio was 2.09 (SD = 1.8). Almost half (46.3%) of available serum assays were in the supra-therapeutic range. Seizures were associated with a higher clozapine dose at one year (OR = 1.003; 95%CI = 1.000-1.006; P value = 0.045) and the presence of positive psychotic symptoms at one year (OR = 4.214; 95%CI = 1.894-9.373; P < 0.001).

CONCLUSION

Compared to existing literature, Indians have a higher rate of clozapine- related seizures and need lower doses to reach therapeutic serum levels.

Clozapine prescription rates in Southeast Europe: A cross-sectional study

Introduction

International reports indicate that clozapine is under prescribed. Yet, this has not been explored in Southeast European (SEE) countries. This cross-sectional study investigates clozapine prescription rates in a sample of 401 outpatients with psychosis from Bosnia and Herzegovina, Kosovo by United Nations resolution, North Macedonia, Montenegro and Serbia.

Methods

Descriptive analysis was used to explore clozapine prescription rates; daily antipsychotic dosage was calculated and converted into olanzapine equivalents. Patients receiving clozapine were compared to those not receiving clozapine; next those that were on clozapine monotherapy were compared to those who were on clozapine polytherapy regime.

Results

It was showed that clozapine was prescribed to 37.7% of patients (with cross-country variation: from 25% in North Macedonia to 43.8% in Montenegro), with average dose of 130.7 mg/daily. The majority of patients on clozapine (70.5%) were prescribed at least one more antipsychotic (the most frequent combination was with haloperidol).

Discussion

Our findings suggested that clozapine prescription rate in SEE outpatients is higher than in Western Europe. The average dose is significantly below the optimal therapeutic dosage recommended by clinical guidelines, and clozapine polytherapy is common. This might indicate that clozapine is prescribed mainly for its sedative effect rather than antipsychotic. We hope that this finding will be taken up by relevant stakeholders to address this non-evidence-based practice.

Exploration of the Barriers to Clozapine Prescribing in Patients with Treatment-Resistant Schizophrenia: A Qualitative Study

Treatment-resistance schizophrenia (TRS) is one of the psychiatric challenges. While clozapine is an effective treatment for patients with TRS, there are some barriers to clozapine prescribing in these patients. The study aims to explore the barriers from Iranian psychiatrists' points of view. The study was conducted by a qualitative approach using content analysis. The Participants included 12 psychiatrists who were selected purposefully. Data were collected using a semi-structured interview from May to December 2020. All interviews were recorded and transcribed and analyzed qualitatively using constant comparisons. Three main categories emerged concerning barriers to the use of clozapine: drug-related barriers, psychiatrist and health system-related barriers, and patient and family-related barriers. Additionally, specific subcategories within each main category were documented. The present study showed that there are three main groups of barriers to the use of clozapine in patients with TRS. Psychiatrist and health system-related barriers may influence the other two groups of barriers. Further research to investigate the effective strategies to overcome the barriers is recommended.

Real-world clinical and cost-effectiveness of community clozapine initiation: mirror cohort study

BACKGROUND

Clozapine is the only drug licensed for treatment-resistant schizophrenia (TRS) but the real-world clinical and cost-effectiveness of community initiation of clozapine is unclear.

AIMS

The aim was to assess the feasibility and cost-effectiveness of community initiation of clozapine.

METHOD

This was a naturalistic study of community patients recommended for clozapine treatment.

RESULTS

Of 158 patients recommended for clozapine treatment, 88 (56%) patients agreed to clozapine initiation and, of these, 58 (66%) were successfully established on clozapine. The success rate for community initiation was 65.4%; which was not significantly different from that for in-patient initiation (58.82%, χ2(1,88) = 0.47, P = 0.49). Following clozapine initiation, there was a significant reduction in median out-patient visits over 1 year (from 24.00 (interquartile range (IQR) = 14.00-41.00) to 13.00 visits (IQR = 5.00-24.00), P < 0.001), and 2 years (from 47.50 visits (IQR = 24.75-71.00) to 22.00 (IQR = 11.00-42.00), P < 0.001), and a 74.71% decrease in psychiatric hospital bed days (z = -2.50, P = 0.01). Service-use costs decreased (1 year: -£963/patient (P < 0.001); 2 years: -£1598.10/patient (P < 0.001). Subanalyses for community-only initiation also showed significant cost reductions (1 year: -£827.40/patient (P < 0.001); 2 year: -£1668.50/patient (P < 0.001) relative to costs prior to starting clozapine. Relative to before initiation, symptom severity was improved in patients taking clozapine at discharge (median Positive and Negative Syndrome Scale total score: initial visit: 80 (IQR = 71.00-104.00); discharge visit 50.5 (IQR = 44.75-75.00), P < 0.001) and at 2 year follow-up (Health of Nation Outcome Scales total score median initial visit: 13.00 (IQR = 9.00-15.00); 2 year follow-up: 8.00 (IQR = 3.00-13.00), P = 0.023).

CONCLUSIONS

These findings indicate that community initiation of clozapine is feasible and is associated with significant reductions in costs, service use and symptom severity.

Pharmacogenomics of Clozapine-induced agranulocytosis: a systematic review and meta-analysis

Although clozapine is the most effective pharmacotherapy for treatment-resistant schizophrenia, it is under-utilized, and initiation is often delayed. One reason is the occurrence of a potentially fatal adverse reaction, clozapine-induced agranulocytosis (CIA). Identifying genetic variations contributing to CIA would help predict patient risk of developing CIA and personalize treatment. Here, we (1) review existing pharmacogenomic studies of CIA, and (2) conduct meta-analyses to identify targets for clinical implementation. A systematic literature search identified studies that included individuals receiving clozapine who developed CIA and controls who did not. Results showed that individuals carrying the HLA-DRB1*04:02 allele had nearly sixfold (95% CI 2.20–15.80, p_corrected = 0.03) higher odds of CIA with a negative predictive value of 99.3%. Previously unreplicated alleles, TNFb5, HLA-B*59:01, TNFb4, and TNFd3 showed significant associations with CIA after multiple-testing corrections. Our findings suggest that a predictive HLA-DRB1*04:02-based pharmacogenomic test may be promising for clinical implementation but requires further investigation.

A Comparison of Attitudes, Comfort, and Knowledge of Clozapine Among Two Diverse Samples of US Psychiatrists

Considerable variation in clozapine utilization exists across the United States, and little is known about the perspective of psychiatrists in states with low clozapine use. To better understand clozapine practices, attitudes, and barriers, a survey was administered to a group of southeastern state conference attendees (SSCA; N = 86). The same survey was administered to psychiatrists belonging to a national community psychiatry organization (AACP; N = 57), and differences were analyzed across the two samples. In comparison to the AACP, the SSCA group felt less comfortable, perceived clozapine as less safe and effective, had fewer patients on clozapine, and were more likely to prefer antipsychotic polypharmacy to clozapine use. Across the sample, use of a myocarditis screening protocol was rare (N = 14/76; 18%) and less than half used plasma antipsychotic levels to guide dosage (N = 60/129; 47%). Continuing professional education on clozapine are needed for psychiatrists who see individuals with psychotic disorders.

Association between previous and future antipsychotic adherence in patients initiating clozapine: real-world observational study

BACKGROUND

Although recognised as the most effective antipsychotic for treatment-resistant schizophrenia, clozapine remains underused. One reason is the widespread concern about non-adherence to clozapine because of poor adherence before initiating clozapine.

AIMS

To determine if prior poor out-patient adherence to treatmentbefore initiating clozapine predisposes to poor out-patient adherence to clozapine or to any antipsychotics (including clozapine) after its initiation.

METHOD

This cohort study included 3228 patients with schizophrenia living in Quebec (Canada) initiating (with a 2-year clearance period) oral clozapine (index date) between 2009 and 2016. Using pharmacy data, out-patient adherence to treatment was measured by the medication possession ratio (MPR), over a 1-year period preceding and following the index date. Five groups of patients were formed based on their prior MPR level (independent variable). Two dependent variables were defined after clozapine initiation (good out-patient adherence to any antipsychotics and to clozapine only). Along with multiple logistic regressions, state sequence analysis was used as a visual representation of antipsychotic-use trajectories over time, before and after clozapine initiation.

RESULTS

Although prior poor adherence to antipsychotics was associated with poor adherence after clozapine initiation, the absolute risk of subsequent poor adherence remained low, regardless of previous adherence level. Most patients adhered to their treatment after initiating clozapine (>68% to clozapine and >84% to any antipsychotics).

CONCLUSIONS

Despite the fact that poor adherence prior to initiating clozapine is widely recognised by clinicians as a barrier for the prescription of clozapine, the current study supports the initiation of clozapine in all eligible patients.

Managing treatment resistance in schizophrenia: A joint study in Hong Kong and Singapore

OBJECTIVE

This study surveyed clinicians in psychiatry in Hong Kong and Singapore to understand their familiarity and prescribing practices in treatment-resistant schizophrenia (TRS) and clozapine-resistant schizophrenia (CRS).

MATERIALS AND METHODS

All clinicians in psychiatry in both regions were invited through email to participate in an anonymous online survey. The survey collected information on the participants' characteristics, their familiarity and experience with clozapine use, and their treatment practices in TRS and CRS. Data collection took place between September 2019 and February 2020 in Hong Kong and December 2018 and March 2019 in Singapore.

RESULTS

261 clinicians responded to the survey, with response rates of 19% (105 out of 556 participants) in Hong Kong and 50% (156 out of 309 participants) in Singapore. The majority of respondents (99.0% in Hong Kong; 87.9% in Singapore) were familiar with treatment guidelines for TRS. However, approximately half (54.2% in Hong Kong; 41.7% in Singapore) delayed the prescription of clozapine when indicated. In terms of alternatives to clozapine, approximately half or more of the clinicians in both regions would use high dose antipsychotics, long-acting injectable antipsychotics, antipsychotic polypharmacy, while the adjuvant use of mood stabilizers and electroconvulsive therapy differed between the two regions. In those with CRS, between 10 and 20% of the respondents added adjuvant mood stabilizers or antipsychotics, and 3-10% would use an antidepressant.

CONCLUSION

Clozapine delays occur in spite of clinicians' familiarity with treatment guidelines. More research is needed to guide the use of augmentation strategies and the search for effective treatments beyond clozapine.

Patients' Experiences of Clozapine for Treatment-Resistant Schizophrenia: A Systematic Review

Background

Clozapine is the most effective antipsychotic for patients with treatment-resistant schizophrenia (TRS), however, it remains widely under-utilized in clinical practice. To date, relatively little attention has been given to patients' experience of clozapine. By synthesizing the existing literature, we sought to determine the experiences of patients with TRS treated with clozapine.

Methods

A systematic review was conducted on Embase, Medline, PsychInfo, and PubMed databases for studies from 1956 to 2021. English language studies and those based on adult patients prescribed clozapine for TRS were included.

Results

Thirteen studies were included with a total of 1487 patients and a narrative synthesis was performed. Overall, most patients reported positive experiences of clozapine, with generally high levels of satisfaction, alongside symptom improvement and preference over previous medications. Negative experiences of clozapine were less common, but when mentioned, focused on blood tests and common side effects, including hypersalivation and weight gain.

Conclusions

This is the first systematic review exploring patients' subjective experiences of clozapine for TRS. Findings suggest that patients generally have a favorable experience when being treated with clozapine. However, conclusions are limited by the risk of bias, particularly survivorship bias. High-quality longitudinal studies exploring patients' experiences of clozapine are indicated for the future.

Underuse of recommended treatments among people living with treatment-resistant psychosis

BACKGROUND

International guidelines recommend that individuals with treatment-resistant psychosis must be treated with clozapine. ECT has also been reported to improve symptom profiles. Identification of clozapine and/or ECT use in real-world practice enables understanding of the extent to which this evidence-base is implemented.

SETTING

Statewide public health tertiary referral service, the Tertiary Referral Service for Psychosis (TRSP), NSW, Australia.

OBJECTIVES

To (i) describe clinical characteristics of individuals with treatment-resistant psychosis and to detail the proportion who had received a trial of clozapine or ECT at any point during their illness course; (ii) describe the characteristics of the treatment trials in both those currently on clozapine and those previously on clozapine; (iii) document reasons in relevant individuals why clozapine had never been used.

METHODS

All TRSP clients who met the criteria for treatment resistance (TR) were included. A detailed casenote review was conducted to examine whether clozapine and/or ECT had ever been prescribed. Characteristics of clozapine and ECT trials were documented. Tertiary service treatment recommendations are described.

FINDINGS

Thirty-six of 48 individuals had TR. They had marked clinical and functional impairment. A minority were currently receiving clozapine (n = 14/36). Most had received a clozapine trial at some point (n = 32/36). Most experienced persistent clinical symptoms while on clozapine (n = 29/32). Clozapine plasma levels were very rarely reported (4/32). Augmentation and antipsychotic polypharmacy were common among those currently on clozapine. The median clozapine trial duration was 4.0 (IQR: 3.0-20.3) months in individuals previously prescribed clozapine. Reasons for clozapine discontinuation included intolerable side effects (n = 10/18) and poor adherence (n = 7/18). One-quarter of TR individuals had trialed ECT (n = 9/36). Tertiary service recommendations included routine plasma monitoring to optimize dose among people currently on clozapine; clozapine retrial in those previously treated; and clozapine initiation for those who had never received clozapine. ECT was recommended to augment clozapine and as an alternative where clozapine trial/retrial was not feasible.

CONCLUSION

Among people with TR referred to a tertiary service, clozapine and ECT were underutilized. Clozapine trials are typically terminated without an adequate trial. Strategies to optimize the use of clozapine therapy and ECT in clinical settings are needed to increase the therapeutic effectiveness of evidence-based therapies for treatment-resistant psychosis.

Cluster Analysis of Clozapine Consumer Perspectives and Comparison to Consumers on Other Antipsychotics

Despite its unique efficacy, clozapine remains underutilized in the United States. Perceptions about clozapine and barriers to its use have been examined among prescribers, but insufficiently studied among consumers. We surveyed 211 antipsychotic consumers (86 on clozapine and 125 on other antipsychotics) on their medication-related perspectives in a public hospital system in Atlanta, Georgia, USA. In contrast to their previous regimen, 72% of clozapine consumers reported they were more satisfied with clozapine. When compared with consumers taking other antipsychotics, clozapine consumers reported more side effects but did not differ on other measures of satisfaction or efficacy. We found Caucasians to be overrepresented among clozapine, as compared to other antipsychotic consumers. Side effects most strongly associated with poor safety ratings were sedation, limb jerking, and dizziness when standing. However, clozapine was only rated less safe by consumers who experienced more than one of these side effects. We used an unsupervised clustering approach to identify three major groups of clozapine consumers. Cluster A (19%) had the lowest safety ratings, aversion to blood work, and a high rate of side effects that associate with lower safety ratings. Cluster B (25%) experienced more hospitalizations and reported satisfaction with clozapine that correlated with efficacy ratings, irrespective of safety ratings. Cluster C (56%) experienced fewer hospitalizations, fewer previous drug trials, greater educational attainment, lower rates of smoking, and rated clozapine more highly. This work identifies common side effects that influence the subjective safety of clozapine and suggests that attitudes toward clozapine depend on context-specific factors.

Patients' and psychiatrists' perspectives on clozapine treatment-a scoping review protocol

INTRODUCTION

The atypical antipsychotic clozapine has shown superior efficacy compared with other antipsychotics and is the gold standard for treating otherwise treatment resistant schizophrenia. However, multiple studies have found that clozapine is underutilised in most parts of the world. A few reviews of literature addressing barriers to clozapine prescribing have been conducted. While there is some variation in the literature included in these reviews, a common feature of the studies included is that they primarily focus on clinical staff's attitudes and perceived barriers for prescribing. Studies of patient perspectives are only sparsely included. A preliminary literature search revealed though, that additional literature on the subject exists, including literature on patient perspectives. It is therefore difficult to conclude if the formerly synthesised literature is representative of current evidence or if the topic has been adequately investigated to inform clinical practice. A scoping review is warranted in order to map and synthesise primary literature on patients' and psychiatrists' perspectives on clozapine treatment, and to identify gaps for future research.

METHODS AND ANALYSIS

The electronic databases Cochrane Library, CINAHL, Web of Science, Psychinfo, MEDLINE and EMBASE will be searched for relevant publications, supplied with searches of Google scholar, The Networked Digital Library of Theses and Dissertations and OpenGrey. Citation tracking of selected studies will furthermore be undertaken. Two researchers will independently screen and extract data. Data will be collated to provide a descriptive summary of the literature, along with a qualitative content analysis of key findings. Identified gaps in research will be accompanied by recommendations for future investigations.

ETHICS AND DISSEMINATION

Findings will be disseminated through a peer-reviewed journal and conference presentations. The scoping review does not require ethics approval.

New approaches to antipsychotic medication adherence - safety, tolerability and acceptability

INTRODUCTION

Antipsychotic pharmacotherapy is considered a first-line treatment in schizophrenia-related disorders and is associated with favorable prognosis and lower mortality rates. However, low adherence rates present a major clinical challenge. In this paper, we will review contemporary approaches to improve adherence to antipsychotic treatment, considering their mechanism of action, safety, tolerability and acceptability.

AREAS COVERED

Novel pharmacological delivery methods included different routes of administration of registered medications (such as intramuscular clozapine preparation and transdermal asenapine), modifications of existing compounds (such as 3-monthly injectable formulation of paliperidone palmitate), and increased interest in oral long-acting medication formulations (such as with penfluridol). In addition, we reviewed innovative technology to monitor adherence, based on the use of electronic digital medicine systems and ingestible sensors.

EXPERT OPINION

All of these diverse approaches were clinically relevant in enhancing treatment adherence and found to be safe and tolerable. The place of each approach is predicated on a personalized approach in each patient, and future research could usefully use large comparative studies to establish robust treatment guidelines. The implementation of new and varied approaches to antipsychotic treatment adherence is welcomed and have the potential to make a significant impact on morbidity in this often difficult-to-treat population.

Use of olanzapine compared with clozapine for treatment-resistant schizophrenia in a real-world setting: nationwide register-based study

BACKGROUND

Clozapine is generally considered as the treatment of choice for patients with treatment-resistant schizophrenia (TRS). However, its superiority has recently been questioned because olanzapine has been suggested as non-inferior to clozapine in its effectiveness.

AIMS

We aimed to investigate the current status of clozapine prescriptions to identify any disparity between clinical guidelines and real-world practices.

METHOD

In this study, we utilised the Health Insurance Review Agency database in the Republic of Korea to investigate the real-world effectiveness of clozapine for patients with TRS. We compared differences in patient variables before and after clozapine administration, and we also performed survival analyses for both psychiatric admissions and emergency room visits among patients who used clozapine or olanzapine.

RESULTS

This study investigated an incident cohort of 64 442 patients, and 2338 patients have been prescribed clozapine. Of these, 998 patients had TRS. In survival analysis, clozapine showed a worse survival rate for psychiatric admissions than olanzapine (hazard ratio 0.615). We also identified that clinicians tended to try a number of antipsychotics, as recommended, before starting patients on clozapine.

CONCLUSIONS

In conclusion, we found that olanzapine led to higher survival rates for psychiatric admissions than clozapine. Thus, considering the risk of serious adverse effects, clozapine may be used conservatively. Considering several studies advocating superior efficacy of clozapine, further studies with extensive data are recommended.

An evaluation of the variation and underuse of clozapine in the United Kingdom

BACKGROUND

Clozapine is the only licensed treatment for treatment refractory schizophrenia. Despite this, it remains grossly underused relative to the prevalence of refractory schizophrenia. The extent of underuse and the degree of regional variation in prescribing in the United Kingdom is unknown. It is also unclear, how the UK compares with other European countries in rates of clozapine prescribing.

METHODS

We obtained data relating to all clozapine prescribing in the UK from the relevant clozapine registries. We examined regional variation in clozapine use across England, corrected for the known prevalence of severe mental illness (SMI). We also compared the UK rate of clozapine use per 100,000 population to that described in other European countries.

FINDINGS

There is substantial variation in clozapine prescribing across different regions of England and only about a third of potentially eligible patients were prescribed the drug in the UK. Clozapine prescribing rate in the UK was lower than in several European countries.

INTERPRETATION

There is clear regional inequity in access to the most effective treatment in refractory schizophrenia in England. Strategies to increase clozapine use, by overcoming both real and perceived barriers, are urgently necessary to reduce treatment inequity for patients with refractory schizophrenia.

Point-of-care measurement of clozapine concentration using a finger-stick blood sample

BACKGROUND

The use of clozapine demands regular monitoring of clozapine plasma concentrations and of white blood cell parameters. The delay between sending blood samples for analysis and receiving the results hinders clinical care. Point-of-care testing (POCT) can provide drug assay results within a few minutes.

AIM

This study aimed to investigate the utility of a novel point-of-care device that can measure clozapine concentrations using capillary blood samples collected via a finger stick.

METHOD

During a five-week period starting in June 2019 eligible patients were asked to provide a finger-stick capillary sample in addition to their usual venous blood sample. Samples were analysed by the novel point-of-care device and by the standard laboratory method. Capillary blood samples were tested by the MyCare™ Insite POCT analyser, and a quantitative measurement of clozapine concentration was provided within six minutes.

RESULTS

A total of 309 patients agreed to measurements by the two methods. Analysis revealed clozapine concentrations in venous blood as determined by the laboratory method ranged from 20 to 1310 ng/mL and by POCT from 7 to 1425 ng/mL. There was a strong positive correlation (R = 0.89) between the results from the venous and the capillary sample methods. The slope of the association between standard assay and MyCare™ Insite was 1.0 with an intercept of -21 ng/mL, indicating minimal bias.

CONCLUSION

Clozapine concentrations can be accurately measured at the point of care using capillary blood samples collected via a finger stick. This approach may be more acceptable than venous sampling to patients and, with almost instant results available, more useful to clinicians.

Prescription attitudes and practices regarding clozapine among Serbian psychiatrists: results of a nationwide survey

OBJECTIVE

Despite clozapine being the most effective treatment for treatment-resistant schizophrenia (TRS), a clear explanation as to why it is underutilized and why its initiation is delayed remains unclear. The first aim of the study was to conduct a nation-wide assessment of both the psychiatrists' attitudes of the obstacles for prescribing clozapine as well as their prescription practices. The second aim was to make recommendations, based on the results obtained, for improving the Serbian clozapine guidelines.

METHODS

A questionnaire was conducted consisting of two parts. One regarded the clinical characteristics of the psychiatrists, while the second contained questions about indications for clozapine initiation, clozapine prescribing tendencies, and barriers to clozapine use. The questionnaire was sent to 302 Serbian psychiatrists.

RESULTS

With 161 out of the 302 psychiatrists returning the questionnaires, the response rate was 53.3%. Nearly 60% of the psychiatrists treated 10 or more patients with clozapine, with TRS being the most common indication. Only four psychiatrists (2.5%) had no patients currently on clozapine. Psychiatrists indicated that their fear of agranulocytosis (68%) constituted the greatest obstacle for clozapine prescription, followed closely by weight gain (56%), and sedation (39%). Despite their fear of agranulocytosis, only 83.9% of the psychiatrists monitored leukocytes regularly.

CONCLUSION

In general, psychiatrists in Serbia seem to be confident in prescribing clozapine, even in the absence of clear monitoring guidelines and the possibility of therapeutic drug monitoring. In order to reduce obstacles for clozapine prescription, monitoring laxity, and an overreliance on personal experience, we recommend three modifications of the existing clozapine guideline.

Using a fingerstick test for haematological monitoring in patients treated with clozapine

BACKGROUND

Treatment with clozapine requires regular blood monitoring in order to minimise the risk of agranulocytosis. The demands on patients and clinicians associated with monitoring may be reduced by using point-of-care, as opposed to lab-based assessments. We assessed the utility of a device that can measure white blood cell (WBC) and neutrophil counts by capillary fingerstick blood.

METHOD

The performance of a small, portable device (HemoCue® WBC DIFF System) was compared with that of a widely used laboratory analyser (ADVIA® 2120i) for measuring WBC and neutrophil counts. Patients with schizophrenia who were being treated with clozapine (n = 201) provided a fingerstick capillary sample and a venous sample for the respective assays.

RESULTS

WBC counts and neutrophil counts from venous blood as determined by ADVIA 2120i, ranged from 3.0 × 10⁹/l to 19.5 × 10⁹/l, and 1.2 × 10⁹/l to 15.9 × 10⁹/l, respectively. There was a strong correlation between the results from venous and the capillary sample methods (WBC: R = 0.89, neutrophil: R = 0.92). By Passing-Bablok regression analysis, the slope of the association between ADVIA^® 2120i and HemoCue WBC DIFF for WBC was 1.0 [95% confidence interval (CI) 0.944-1.086], with intercept at -0.9 (95% CI -1.43 to -0.45). For neutrophils, the slope was 0.870 (95% CI 0.817-0.923), with intercept at -0.19 (95% CI -0.43 to 0.02). Overall, mean biases of -0.95 × 10⁹/l for WBC, and -0.91 × 10⁹/l for neutrophils were observed for the capillary blood method compared with the venous blood method. Below the clinical cutoff intervals for clozapine monitoring WBC (<3.5 × 10⁹/l) and neutrophils (<1.5 × 10⁹/l) these biases were -1.1 × 10⁹/l for WBC, and -0.25 × 10⁹/l for neutrophils.

CONCLUSION

Results from the capillary blood HemoCue WBC DIFF analyser compared well with the venous blood ADVIA 2120i analyser for determining WBC and neutrophil counts. There was a slight overall bias, with the capillary method reporting lower values for both measures. Fingerstick point-of-care analysis is suitable for monitoring blood counts in patients on clozapine, although confirmatory standard venous testing is recommended for test results falling below accepted thresholds.

A Working Hypothesis Regarding Identical Pathomechanisms between Clinical Efficacy and Adverse Reaction of Clozapine via the Activation of Connexin43

Clozapine (CLZ) is an approved antipsychotic agent for the medication of treatment-resistant schizophrenia but is also well known as one of the most toxic antipsychotics. Recently, the World Health Organization’s (WHO) global database (VigiBase) reported the relative lethality of severe adverse reactions of CLZ. Agranulocytosis is the most famous adverse CLZ reaction but is of lesser lethality compared with the other adverse drug reactions of CLZ. Unexpectedly, VigiBase indicated that the prevalence and relative lethality of pneumonia, cardiotoxicity, and seizures associated with CLZ were more serious than that of agranulocytosis. Therefore, haematological monitoring in CLZ patients monitoring system provided success in the prevention of lethal adverse events from CLZ-induced agranulocytosis. Hereafter, psychiatrists must amend the CLZ patients monitoring system to protect patients with treatment-resistant schizophrenia from severe adverse CLZ reactions, such as pneumonia, cardiotoxicity, and seizures, according to the clinical evidence and pathophysiology. In this review, we discuss the mechanisms of clinical efficacy and the adverse reactions of CLZ based on the accumulating pharmacodynamic findings of CLZ, including tripartite synaptic transmission, and we propose suggestions for amending the monitoring and medication of adverse CLZ reactions associated with pneumonia, cardiotoxicity, and seizures.

Prevalence of treatment resistance and clozapine use in early intervention services

BACKGROUND

Treatment resistance causes significant burden in psychosis. Clozapine is the only evidence-based pharmacologic intervention available for people with treatment-resistant schizophrenia; current guidelines recommend commencement after two unsuccessful trials of standard antipsychotics.

AIMS

This paper aims to explore the prevalence of treatment resistance and pathways to commencement of clozapine in UK early intervention in psychosis (EIP) services.

METHOD

Data were taken from the National Evaluation of the Development and Impact of Early Intervention Services study (N = 1027) and included demographics, medication history and psychosis symptoms measured by the Positive and Negative Syndrome Scale (PANSS) at baseline, 6 months and 12 months. Prescribing patterns and pathways to clozapine were examined. We adopted a strict criterion for treatment resistance, defined as persistent elevated positive symptoms (a PANSS positive score ≥16, equating to at least two items of at least moderate severity), across three time points.

RESULTS

A total of 143 (18.1%) participants met the definition of treatment resistance of having continuous positive symptoms over 12 months, despite treatment in EIP services. Sixty-one (7.7%) participants were treatment resistant and eligible for clozapine, having had two trials of standard antipsychotics; however, only 25 (2.4%) were prescribed clozapine over the 12-month study period. Treatment-resistant participants were more likely to be prescribed additional antipsychotic medication and polypharmacy, instead of clozapine.

CONCLUSIONS

Prevalent treatment resistance was observed in UK EIP services, but prescription of polypharmacy was much more common than clozapine. Significant delays in the commencement of clozapine may reflect a missed opportunity to promote recovery in this critical period.

Effect of age on the relative efficacy of clozapine in schizophrenia

OBJECTIVE

Early treatment of schizophrenia improves outcomes. Clozapine appears to have unique benefit when other antipsychotic medication has failed. This systematic review and meta-analysis aims to assess clozapine's superiority over alternative antipsychotic medication and examine whether earlier use is associated with additional benefit.

METHOD

Systematic retrieval of blinded, randomized controlled trials comparing clozapine with alternative antipsychotics in adults with schizophrenia. The effect of mean age on relative clozapine response was examined using random effects meta-regression, and multiple linear regression on available patient data.

RESULTS

A total of 276 studies were retrieved. Thirty-four studies were included in the meta-analysis. Clozapine was significantly more effective than alternative antipsychotics in reducing psychotic symptoms and increasing response. However, meta-regression failed to show a more significant effect in younger patients (age on effect size (total psychotic symptoms) 0.00, P = 0.79 CI -0.03 to 0.03). Individual patient data were available for two studies, the larger of which showed a significant interaction between younger age and superiority of clozapine.

CONCLUSION

The results support clozapine's superiority over other antipsychotics. A convincing effect of age on this effect was not demonstrated, although this was suggested in one study. In view of the age of many of the included studies, and changes in reporting practice over time, new clozapine RCTs, which include age of illness onset as well as age at trial time, would be welcome in order to provide meta-analysable data for future use.

Educational needs and psychoeducation interventions in clozapine users: a narrative review

OBJECTIVE

Increasing users' knowledge about the expected benefits and risks of clozapine may contribute to the initiation and maintenance of clozapine in persons with treatment-resistant schizophrenia (TRS). The objective was to identify the educational needs of clozapine users and the interventions aimed at addressing these needs.

METHOD

We systematically searched multiple electronic databases for articles: (i) exploring educational needs of clozapine users and of their relatives; and (ii) reporting educational interventions aimed at addressing these needs. Data were synthesized narratively.

RESULTS

A total of 30 articles published from 1990 to 2019 in 8 countries fulfilled our inclusion criteria. As most studies on educational needs (n = 18) were carried out in persons already taking clozapine, educational needs of TRS patients who were candidates for clozapine treatment are not well documented. Users' level of knowledge about clozapine was often poor, especially about adverse effects or interactions with other substances, with a poor retention of information delivered at treatment initiation. Among 12 studies reporting educational interventions in clozapine users, five provided quantitative outcomes. Their findings suggest that structured educational programmes may contribute to promote clozapine initiation and to improve users' knowledge about this drug.

CONCLUSION

The literature is sparse on structured educational interventions about clozapine, and only one randomized controlled trial was identified. A promising strategy emerging from this review may be staging educational interventions according to the evolving needs of persons with TRS before clozapine use, at initiation and during maintenance treatment.

Delaying clozapine: how long is too long?

Background

Although clozapine is the most effective drug for treatment-resistant schizophrenia, its use remains restricted in clinical practice in India. The delay in initiating treatment with clozapine and its impact on disease outcome needs evaluation.

Aim

To identify the implications of delaying clozapine initiation in clinical outcomes among people with treatment-resistant schizophrenia.

Methods

Subjects with treatment-resistant schizophrenia, stabilised on clozapine monotherapy, were recruited from the outpatient clinic of a general hospital psychiatry unit offering tertiary care services in Thrissur district, Kerala, India. A retrospective cohort design was employed, and information on duration of illness, total duration of treatment and duration of treatment with clozapine was collected. Present symptom status was measured using the Positive and Negative Syndrome Scale. Factors associated with higher symptom scores were analysed using an independent sample t test, Spearman correlation and multiple linear regression.

Results

Forty subjects stabilised on long-term clozapine therapy formed the study sample. The mean dose of clozapine used in the study population was 200 mg. The mean duration of antipsychotic treatment before starting clozapine was 89.3 months (7.4 years). The duration of treatment before starting clozapine was found to have a significant positive association with the total Positive and Negative Syndrome Scale score (correlation coefficient 0.40; p=0.01) and negative symptom score (correlation coefficient 0.33; p=0.04). The multiple regression analysis adjusting for covariates showed that the duration of treatment before starting clozapine was an independent factor associated with a higher negative symptom score in the Positive and Negative Syndrome Scale (slope β=0.05; p=0.02; R²=0.27).

Conclusion

Poor treatment outcomes in treatment-resistant schizophrenia could be secondary to a delay in initiating clozapine therapy.

Clozapine use - has practice changed?

BACKGROUND

One-third of individuals with schizophrenia have treatment-resistant illness. Of these, up to 60% will respond to clozapine treatment.

AIMS

This study retrospectively examined clozapine prescribing patterns against National Institute for Health and Care Excellence (NICE) guidelines as treatment-resistant illness emerged in a first-episode psychosis cohort.

METHODS

A total of 339 individuals with a first-episode psychosis were included in the study. Clozapine prescribing patterns were compared against the NICE guidelines and the impact of clozapine use on one index of service utilisation (hospitalisation) was assessed.

RESULTS

A total of 32 individuals (9.4%) from the cohort were prescribed clozapine. The mean time to clozapine trial was 2.1 years (SD 1.95; range 0.17-6.25). The mean number of adequate trials of antipsychotic prior to starting clozapine was 2.74 (SD 1.13; range 1-5). Following clozapine initiation, mean hospital admissions per year reduced from 2.3 to 0.3 (p=0.00). Mean hospital days pre- and post-clozapine also reduced (147 vs. 53; p=0.00). In total, 18 patients discontinued clozapine use during follow-up - 5 temporarily and 13 permanently.

CONCLUSIONS

Patients are being prescribed clozapine earlier than previously demonstrated, though delays are still evident, and many patients discontinue treatment. More work needs to be undertaken to understand and address factors which lead to its discontinuation.

Delegating Clozapine Monitoring to Advanced Nurse Practitioners: An Exploratory, Randomized Study to Assess the Effect on Prescription and Its Safety

To test whether: (1) psychiatrists will prescribe clozapine more often if they can delegate the monitoring tasks to an advanced nurse practitioner (ANP), (2) clozapine monitoring by an ANP is at least as safe as monitoring by a psychiatrist. Patients from 23 Dutch outpatient teams were assessed for an indication for clozapine. ANPs affiliated to these teams were randomized to Condition A: clozapine monitoring by an ANP, or Condition B: monitoring by the psychiatrist. The safety of monitoring was evaluated by determining whether the weekly neutrophil measurements were performed. Staff and patients were blinded regarding the first hypothesis. Of the 173 patients with an indication for clozapine at baseline, only seven in Condition A and four in Condition B were prescribed clozapine (Odds Ratio = 2.24, 95% CI 0.61–8.21; p = 0.225). These low figures affected the power of this study. When we considered all patients who started with clozapine over the 15-month period (N = 49), the Odds Ratio was 1.90 (95% CI 0.93–3.87; p = 0.078). With regard to the safety of the monitoring of the latter group of patients, 71.2% of the required neutrophil measurements were performed in condition A and 67.3% in condition B (OR = 0.98; CI = 0.16–3.04; p = 0.98). Identifying patients with an indication for clozapine does not automatically lead to improved prescription rates, even when an ANP is available for the monitoring. Clozapine-monitoring performed by an ANP seemed as safe as that by a psychiatrist.

How and when to use clozapine

OBJECTIVE

Clozapine is the only approved strategy for treatment-resistant schizophrenia, although it is highly underutilized. We aim to generate practical and actionable evidence-based recommendations for the use of this drug considering prescription barriers.

METHOD

Narrative review.

RESULTS

A consistent body of evidence supports the efficacy of clozapine reducing morbidity and mortality in schizophrenia. The main obstacles to its use are the lack of experience by prescribers and perceived treatment burden. Systematic screening of eligibility, utilization of available resources for consultation, developing a professional network with other stakeholders, as well as optimizing how clozapine is presented to patients is discussed. Furthermore, specific evidence-based recommendations for initiation, maintenance, and safety monitoring with clozapine are provided.

CONCLUSION

Clozapine prescription is one of the areas in psychiatry with the greatest mismatch between efficacy and utilization in clinical practice. Although multiple barriers to the use of clozapine exist, some of these may be overcome by updates of routine clinical practice.

Comfort Level and Barriers to the Appropriate Use of Clozapine: a Preliminary Survey of US Psychiatric Residents

OBJECTIVE

Clozapine is the gold standard treatment for treatment-resistant schizophrenia. Prior surveys of mental health providers have identified multiple causes for underutilization of clozapine; however, no previous survey has been conducted to assess US psychiatry residents' level of comfort in prescribing clozapine.

METHODS

A survey was sent via email to program directors of Accreditation Council for Graduate Medical Education-affiliated psychiatry residency programs requesting the survey to be distributed to current residents. The survey included questions regarding demographics, clozapine-prescribing practices, comfort levels with prescription, and perceived barriers to prescription.

RESULTS

A total of 164 psychiatric residents completed the survey, 37% PGY-1 and 2 residents and 63% PGY-3 or higher. One-third of the respondents had a clozapine clinic in their program. Only 18% of the residents felt "very" comfortable in initiating clozapine and 41% felt "somewhat" comfortable. Two main reasons for not starting clozapine were (1) side effect profile (41%) and (2) limited experience and inadequate training in clozapine use (38%). More than 4/5ths of the residents (83%) responded that they would feel more comfortable in prescribing clozapine if they were trained in a clozapine clinic. Major limitation of this study has been the small sample size, lack of representativeness, and generalization.

CONCLUSIONS

Forty-one percent of the respondents did not feel comfortable with clozapine prescription. Major concerns cited included the side effect profile as well as lack of experience and training. The majority of the respondents felt that they would be more comfortable prescribing clozapine if they had the opportunity to train in a clozapine clinic.

Demographic and clinical features as predictors of clozapine response in patients with schizophrenia spectrum disorders: A systematic review and meta-analysis

OBJECTIVES

Clozapine (CLZ) is prescribed to (relatively) treatment-resistant patients with schizophrenia spectrum disorders. Currently, it is unknown what factors predict response to CLZ. Therefore, we performed meta-analyses to identify predictors of CLZ response, hence aiming to facilitate timely and efficient prescribing of CLZ.

METHODS

A systematic search was performed in 'Pubmed' and 'Embase' until 1 January 2019. Articles were eligible if they provided data on predictors of CLZ response measured demographic and clinical factors at baseline or biochemical factors at follow-up in schizophrenia spectrum disorder patients.

RESULTS

A total of 34 articles, total number of participants = 9386; N unique = 2094, were eligible. Factors significantly associated with better CLZ response were: lower age, lower PANSS negative score and paranoid schizophrenia subtype.

CONCLUSION

The results of our meta-analyses suggest that three baseline demographic and clinical features are associated with better clozapine response, i.e. relatively young age, few negative symptoms and paranoid schizophrenia subtype. These variables may be taken into account by clinicians who consider treating a specific patient with CLZ.

Polypharmacy in schizophrenia

Schizophrenia is a severe mental disorder characterized by a heterogeneous symptom profile which comprises a clinical platform for widespread use of polypharmacy even though antipsychotic monotherapy is the recommended treatment regimen. This narrative review provides a summary of the current gap between evidence and practice for use of antipsychotic combination therapy in patients with schizophrenia. Antipsychotic polypharmacy is frequently prescribed instead of following international consensus of clozapine monotherapy in treatment-resistant patients. Antipsychotic-benzodiazepine combination therapy clearly has a role in the treatment of acute agitation whereas there is no evidence to support an effect on core schizophrenia symptoms when chronically prescribed. Antidepressants are typically added to antipsychotic treatment in case of persistent negative symptoms. Available evidence suggests that antidepressants may improve negative symptom control in schizophrenia. Combining an antipsychotic with an antiepileptic is not supported by any firm evidence, but individual mood stabilizers have come out positively in single trials. Generally, the evidence base for polypharmacy in schizophrenia maintenance treatment is sparse but may be warranted in certain clinical situations. Therapeutic benefits and side effects should be carefully monitored and considered to ensure a beneficial risk-benefit ratio if prescribing polypharmacy for specific clinical indications.

Evidence-based guidelines for the pharmacological treatment of schizophrenia: Updated recommendations from the British Association for Psychopharmacology

These updated guidelines from the British Association for Psychopharmacology replace the original version published in 2011. They address the scope and targets of pharmacological treatment for schizophrenia. A consensus meeting was held in 2017, involving experts in schizophrenia and its treatment. They were asked to review key areas and consider the strength of the evidence on the risk-benefit balance of pharmacological interventions and the clinical implications, with an emphasis on meta-analyses, systematic reviews and randomised controlled trials where available, plus updates on current clinical practice. The guidelines cover the pharmacological management and treatment of schizophrenia across the various stages of the illness, including first-episode, relapse prevention, and illness that has proved refractory to standard treatment. It is hoped that the practice recommendations presented will support clinical decision making for practitioners, serve as a source of information for patients and carers, and inform quality improvement.

One-Year Outcome and Adherence to Pharmacological Guidelines in First-Episode Schizophrenia: Results From a Consecutive Cohort Study

BACKGROUND

Remission in schizophrenia is difficult to achieve. Antipsychotic drugs are critical in the treatment of schizophrenia. International guidelines for the pharmacological treatment of schizophrenia recommend a 3-step algorithm with clozapine being the third-line antipsychotic agent. This study investigated the 1-year outcome and the application of the guidelines for the pharmacological treatment of nonremitted first-episode schizophrenia (FES) patients during the first year of follow-up.

METHODS

A sample of 78 FES patients from the Norwegian TIPS (Early Treatment and Intervention in Psychosis) 2 study was assessed at the end of the first year of follow-up. The symptom remission criteria were those defined by the Remission in Schizophrenia Working Group. The adherence to the pharmacological guidelines was assessed by reading the medical files and by a digital search of the words "clozapine," "klozapin," and "Leponex" in the hospital electronic data system.

RESULTS

The majority (n = 53, 67.9%) of the patients included were nonremitted at the 1-year follow-up. The majority of the nonremitted patients received either none (7.5%), one (56.6%), or 2 types (15.1%) of antipsychotic drugs during the first year of follow-up. Only 2 (3.8%) received treatment with clozapine, and 3 (5.7%) in total were offered it.

CONCLUSIONS

For our FES sample, there was a low 1-year remission rate and a poor adherence to the pharmacological guidelines. Higher adherence to treatment guidelines with a more intensified antipsychotic treatment, which in some cases will include clozapine, will enhance the quality of treatment and may enhance the rates of remission for schizophrenia.

Clozapine and cardiotoxicity - A guide for psychiatrists written by cardiologists

This review discusses the rare but potentially life-threatening cardiovascular side-effects of myocarditis and dilated cardiomyopathy associated with the use of Clozapine. The clinical presentation of these conditions is non-specific, making it difficult to both risk-stratify and identify patients who develop these consequences. This review aims to examine the proposed aetiologies, diagnostic approaches and subsequent management strategies of cardiotoxicity associated with clozapine use; offering guidance to psychiatrists and general physicians. Current evidence highlights the importance of accurate diagnosis to prevent premature and unnecessary cessation of clozapine. Guidance on monitoring and reintroduction of the drug is emerging and current practice recommends a combination of regular monitoring of biomarkers and imaging to make a diagnosis of cardiotoxicity although further work is needed to establish evidence-based guidelines.

Patient characteristics, burden and pharmacotherapy of treatment-resistant schizophrenia: results from a survey of 204 US psychiatrists

BACKGROUND

Minimal/non-response to antipsychotic treatment, and persistent positive symptoms despite treatment, are common among patients with schizophrenia. The aim of this study was to characterize a US treatment-resistant schizophrenia (TRS) population in terms of patient demographics, burden of symptoms, treatment history, and factors influencing therapeutic choice.

METHODS

In an online survey, 204 psychiatrists self-selected and completed three patient records: two TRS and one schizophrenia ('non-TRS').

RESULTS

Respondents reported that 29.5% of their schizophrenia caseload had TRS. Selected TRS (n = 408) vs non-TRS (n = 204) patients were more likely to be unemployed (74.5% vs 45.1%, p < 0.001), hospitalized at least once (93.4% vs 74.0%, p < 0.001), and to have physical/psychiatric comorbidities including obesity (40.2% vs 23.5%, p < 0.001) and depression (38.7% vs 25.0%, p = 0.001). Psychiatric symptoms were more frequent and severe in TRS, and interfered more with social and functioning domains. Of positive symptoms, eliminating delusions and hallucinations was considered most important to improve a patient's long-term prognosis. In TRS, clozapine monotherapy was the most common treatment (15.9%), though ranked fifth of ten options to treat TRS. Psychiatrists typically increased the antipsychotic dose or added a second antipsychotic before initiating clozapine or switching antipsychotics. Antipsychotic switches were most commonly due to lack of efficacy (TRS = 71.4% vs non-TRS = 54.3%, p < 0.001) and intolerability (34.4% vs 38.4%, p = 0.22) with the prior antipsychotic. Persistent hallucinatory behavior was the top symptom leading to treatment switches in TRS (63.9% vs 37.1%, p < 0.001).

CONCLUSIONS

According to psychiatrists, symptoms have a greater clinical burden on patients with TRS than non-TRS. TRS is commonly managed by antipsychotic dose increases/combinations, with clozapine the fifth preference despite being the only approved TRS medication. New treatments are needed for patients who do not respond to available antipsychotics.

Prevalence of treatment-resistant psychoses in the community: A naturalistic study

BACKGROUND

Treatment-resistant schizophrenia (TRS) is a major cause of disability. Clozapine is currently the only antipsychotic medication licensed for its treatment. However, the rate of treatment resistance among outpatients with schizophrenia or other psychoses, and the rate of use of clozapine among them, is not known.

AIMS

The aims of this study are (a) to determine the point prevalence of treatment-resistant psychosis in a community sample, and (b) to determine the number of patients with TRS who have never had a clozapine trial.

METHOD

Clinico-demographic data were extracted from the case notes for 202 patients from two community mental-health teams.

RESULTS

We found that 56% (99/176) had a diagnosis of TRS, and 52% (51/99) of these patients had never been treated with clozapine. Patients of non-white ethnicity were less likely to have had a clozapine trial (p=0.009). The point prevalence of treatment resistance within the bipolar affective disorder sample was 19% (5/26).

CONCLUSION

These findings suggest that TRS is common in the community mental-health team, and a large proportion of these patients have not received clozapine. These findings indicate that identifying and treating treatment resistance should be a focus of community services for schizophrenia.

Need to bleed? Clozapine haematological monitoring approaches a time for change

Regular haematological monitoring during clozapine treatment reduces the risk of complications and death from clozapine-related blood dyscrasias. However, many patients in the course of clozapine treatment develop neutropenia unrelated to drug treatment which leads to treatment discontinuation. The minimum haematological threshold allowed for the continuation of clozapine treatment was recently lowered in the US, but not in the UK. In this case series, we present four cases where lowering the haematological cut-off to that used in the US, allowed treatment continuation. Lowering the current UK threshold for clozapine cessation could avoid unnecessary interruptions in treatment with minimal impact on safety.

Comparison of Clinical Characteristics Between the Patients with Schizophrenia on Clozapine Treatment with Those Taking Combination of Long-Acting Injectable and Oral Antipsychotics

INTRODUCTION

The primary aim of this study was to compare clinical characteristics between the patients with schizophrenia on clozapine treatment with those under combination of long-acting injectable and oral antipsychotics (combined treatment), and the secondary aim was to evaluate the impact of obsessive-compulsive disorder (OCD) comorbidity on the clinical variables.

METHODS

The patients with schizophrenia applied at Outpatient Psychiatry Clinic of the University between October 2017 and March 2018 taking clozapine or combined treatment were included in the study. The participants were administered Brief Psychiatric Rating Scale (BPRS), Clinical Global Impressions Scale, Scale for the Assessment of Positive and Negative Symptoms (SAPS/SANS), Calgary Depression Scale for Schizophrenia (CDSS), Yale-Brown Obsessive Compulsive Scale (YBOCS), Turkish version of Schedule for Assessing the three components of insight (SAI), and Global Assessment of Functioning Scale (GAF).

RESULTS

Patients on clozapine had higher Y-BOCS, BPRS, SANS, CDSS scores, and lower GAF scores compared to those taking combined antipsychotics (p<0.05). OCD comorbidity rate was 13% in the combination therapy group and 36% in clozapine users. The SAPS scores were higher but CDSS scores were lower in clozapine users with the presence of OCD comorbidity (p<0.05).

CONCLUSION

Clozapine and combined therapy groups differed widely by the clinical characteristics of the patients in this study. Both groups showed a high OCD comorbidity rate in this study and OCD comorbidity should be considered when schizophrenia treatment is initiated to obtain more satisfactory results. Furthermore, patients on clozapine seem to show a different relationship with OCD comorbidity compared to those under combined treatment.

Differences between physicians' and nurse practitioners' viewpoints on reasons for clozapine underprescription

INTRODUCTION

Clozapine (CLZ) is the only proven effective therapy for treatment-resistant schizophrenia, but it is underutilized across the globe. Previous findings suggest a lack of experience with CLZ prescription and concerns about CLZ's pharmacological characteristics are the prime reasons for CLZ underutilization. To our knowledge, it is currently unknown whether the reasons for underutilization and suggested solutions differ between physicians and nurse practitioners. Such differences are important as nurse practitioners are becoming increasingly involved in prescribing CLZ.

METHODS

To examine to what degree physicians and nurse practitioners differ with regard to their take on reasons for CLZ underutilization and suggested solutions, an online questionnaire was distributed to physicians and nurse practitioners. The primary outcome was to compare the patient-related and prescriber-related reasons for CLZ underprescription between physicians and nurse practitioners, while secondary outcome measures included the potential solutions to prevent this underprescription.

RESULTS

Physicians (N = 112) and nurse practitioners (N = 41) agreed that the two most common reasons for underprescription (patient-related and prescriber-related) were refusal to undergo regular blood tests and side-effect concerns. They also agreed that the third most common prescriber-related reason was medical complications. Physicians rated patients' unwillingness to switch medication as the third most common reason for CLZ underprescription, whereas nurse practitioners rated refusal to undergo baseline bloodtests as the third most common reason. The solutions to reduce underprescription largely corresponded between both groups.

CONCLUSIONS

We conclude that slight differences exist between physicians' and nurse practitioners' viewpoints on patient-related and prescriber-related reasons for CLZ underprescription. Future research projects should involve patients to elucidate whether the patient-related factors put forward by prescribers align with the patients' opinions.