Primary Nonadherence to Antipsychotic Treatment Among Persons with Schizophrenia

Not obtaining a medication the first time it is prescribed: primary non-adherence to cardiovascular pharmacotherapy

Primary medication non-adherence describes the situation when a first prescription for a new medication is never filled. Primary non-adherence is an important, yet understudied aspect of reduced effectiveness of pharmacotherapy. This review summarizes the frequency, impact, reasons, predictors, and interventions regarding primary non-adherence to cardiovascular/cardiometabolic drugs. The current literature reveals a high prevalence of primary non-adherence. The individual risk of primary non-adherence is determined on multiple factors, e.g., primary non-adherence of lipid-lowering drugs is higher compared to antihypertensive medications. However, the overall rate of primary non-adherence is > 10%. Additionally, this review identifies specific areas for research to better understand why patients forgo evidence-based beneficial pharmacotherapy and to explore targeted interventions. At the same time, measures to reduce primary non-adherence-once proven to be effective-may represent an important new opportunity to reduce cardiovascular diseases.

Treatment adherence in forensic patients with schizophrenia spectrum disorders discharged on long-acting injectable antipsychotics: a comparative 3-year mirror-image study

In this retrospective 3-year mirror-image study, 81 patients with schizophrenia spectrum disorders (SSD) were categorized according to whether they were prescribed long-acting injectable antipsychotics (LAI) or not upon discharge from the inpatient forensic psychiatric unit. Antipsychotic adherence, which was staged based on the 'proportion of days covered' method, as well as other clinical outcomes was compared between pre- and post-index mirror periods. In both Oral-only (n = 46) and Oral + LAI (n = 35) groups, the number of hospitalizations, convictions and months spent in the hospital were significantly lower in the post-index period than the pre-index period. Differences in these three variables between pre- and post-index periods were NS between the two groups. A mixed effect ordinal logistic regression model with random intercept showed that the odds ratio of obtaining a higher treatment adherence score in the post-index period was more pronounced in the Oral + LAI group than in the Oral-only group, considering adherence at baseline and the length of stay during the index hospitalization as potential confounders. Discharge with LAIs in a forensic psychiatric cohort of SSD was associated with a greater mid- to long-term improvement in antipsychotic medication adherence compared to discharge with oral-only antipsychotics.

Revealing the reporting disparity: VigiBase highlights underreporting of clozapine in other Western European countries compared to the UK

BACKGROUND

Pharmacovigilance studies indicate clozapine history is marked by adverse drug reactions (ADRs).

OBJECTIVE

In a 2021 article, the United Kingdom (UK) had >90 % of European clozapine-related fatal outcomes in VigiBase, the World Health Organization's pharmacovigilance database. Two possibly opposing hypotheses could explain this disparity: 1) fewer reported fatal outcomes in other Western European countries mainly reflect underreporting to VigiBase, and 2) the higher number of UK reports reflects higher real relative mortality.

METHODS

VigiBase reports from clozapine's introduction to December 31, 2022, were studied for ADRs and the top 10 causes of fatal outcomes. The UK was compared with 11 other top reporting Western countries (Germany, Denmark, France, Finland, Ireland, Italy, Netherlands, Norway, Spain, Sweden and Switzerland). Nine countries (except Ireland and Switzerland) were compared after controlling for population and clozapine prescriptions.

RESULTS

The UK accounted for 29 % of worldwide clozapine-related fatal outcomes, Germany 2 % and <1 % in each of the other countries. The nonspecific label "death" was the top cause in the world (46 %) and in the UK (33 %). "Pneumonia" was second in the world (8 %), the UK (12 %), Ireland (8 %) and Finland (14 %). Assuming that our corrections for population and clozapine use are correct, other countries underreported only 1-10 % of the UK clozapine fatal outcome number.

CONCLUSIONS

Different Western European countries consistently underreport to VigiBase compared to the UK, but have different reporting/publishing styles for clozapine-related ADRs/fatal outcomes. Three Scandinavian registries suggest lives are saved as clozapine use increases, but this cannot be studied in pharmacovigilance databases.

Response rates to sequential trials of antipsychotic medications according to algorithms or treatment guidelines in psychotic disorders. A systematic review and meta-analysis

BACKGROUND

There is a relative lack of research evaluating the outcomes when treatment guidelines or algorithms for psychotic disorders are followed. This systematic review and meta-analysis determined the response rates to antipsychotic medications at different stages of these algorithms and whether these response rates differ in first episode cohorts.

METHODS

Data sources: A systematic search strategy was conducted across four databases PubMed, EMBASE, PsycINFO (Ovid) and CINAHL. Studies that had sequential trials of different antipsychotic medications were included. A meta-analysis of proportions was performed using random effects models and sub-group analysis in first episode psychosis studies.

RESULTS

Of the 4078 unique articles screened, fourteen articles, from nine unique studies, were eligible and included 2522 participants. The proportion who experienced a response to any antipsychotic in the first stage of an algorithm was 0.53 (95 % C.I.:0.38,0.68) and this decreased to 0.26 (95 % C.I.:0.15,0.39) in the second stage. When clozapine was used in the third stage, the proportion that achieved a response was 0.43 (95 % C.I. 0.19, 0.69) compared to 0.26 (95 % C.I.:0.05,0.54) if a different antipsychotic was used. Four studies included 907 participants with a first episode of psychosis and the proportions that achieved a response were: 1st stage: 0.63 (95 % C.I.: 0.45, 0.79); 2nd stage: 0.34 (95 % C.I.:0.16,0.55); clozapine 3rd stage: 0.45 (95 % C.I.:0.0,0.97), different antipsychotic 3rd stage: 0.15 (95 % C.I.,0.01,0.37).

DISCUSSION

These findings support the recommendation to have a trial of clozapine after two other antipsychotic medications have been found to be ineffective.

Exploring low clozapine C/D ratios, inverted clozapine-norclozapine ratios and undetectable concentrations as measures of non-adherence in clozapine patients: A literature review and a case series of 17 patients from 3 studies

BACKGROUND

Up to 1/2 of outpatients prescribed clozapine may be partially/fully non-adherent, based on therapeutic drug monitoring (TDM). Three indices for measuring partial/full non-adherence are proposed a: 1) clozapine concentration/dose (C/D) ratio which drops to half or more of what is expected in the patient; 2) clozapine/norclozapine ratio that becomes inverted; and 3) clozapine concentration that becomes non-detectable.

METHODS

These 3 proposed indices are based on a literature review and 17 cases of possible non-adherence from 3 samples: 1) an inpatient study in a Chinese hospital, 2) an inpatient randomized clinical trial in a United States hospital, and 3) and a Uruguayan outpatient study.

RESULTS

The first index of non-adherence is a clozapine C/D ratio which is less than half the ratio corresponding to the patient's specific ancestry group and sex-smoking subgroup. Knowing the minimum therapeutic dose of the patient based on repeated TDM makes it much easier to establish non-adherence. The second index is inverted clozapine/norclozapine ratios in the absence of alternative explanations. The third index is undetectable concentrations. By using half-lives, the chronology of the 3 indices of non-adherence was modeled in two patients: 1) the clozapine C/D ratio dropped to ≥1/2 of what is expected from the patient (around day 2); 2) the clozapine/norclozapine ratio became inverted (around day 3); and 3) the clozapine concentration became undetectable by the laboratory (around days 9-11).

CONCLUSION

Prospective studies should further explore these proposed clozapine indices in average patients, poor metabolizers (3 presented) and ultrarapid metabolizers (2 presented).

The excitatory-inhibitory balance as a target for the development of novel drugs to treat schizophrenia

The intricate balance between excitation and inhibition (E/I) in the brain plays a crucial role in normative information processing. Dysfunctions in the E/I balance have been implicated in various psychiatric disorders, including schizophrenia (SCZ). In particular, abnormalities in GABAergic signaling, specifically in parvalbumin (PV)-containing interneurons, have been consistently observed in SCZ pathophysiology. PV interneuron function is vital for maintaining an ideal E/I balance, and alterations in PV interneuron-mediated inhibition contribute to circuit deficits observed in SCZ, including hippocampus hyperactivity and midbrain dopamine system overdrive. While current antipsychotic medications primarily target D2 dopamine receptors and are effective primarily in treating positive symptoms, novel therapeutic strategies aiming to restore the E/I balance could potentially mitigate not only positive symptoms but also negative symptoms and cognitive deficits. This could involve, for instance, increasing the inhibitory drive onto excitatory neurons or decreasing the putative enhanced pyramidal neuron activity due to functional loss of PV interneurons. Compounds targeting the glycine site at glutamate NMDA receptors and muscarinic acetylcholine receptors on PV interneurons that can increase PV interneuron drive, as well as drugs that increase the postsynaptic action of GABA, such as positive allosteric modulators of α5-GABA-A receptors, and decrease glutamatergic output, such as mGluR2/3 agonists, represent promising approaches. Preventive strategies aiming at E/I balance also represent a path to reduce the risk of transitioning to SCZ in high-risk individuals. Therefore, compounds with novel mechanisms targeting E/I balance provide optimism for more effective and tailored interventions in the management of SCZ.

Evaluation of adherence to pharmacological treatments by undocumented migrants with chronic diseases: a 10-year retrospective cohort study

OBJECTIVES

To investigate the time course of medication adherence and some of the factors involved in this process in undocumented migrants with chronic diseases.

DESIGN

Retrospective cohort study.

SETTING

A big non-governmental organisation in Milano, Italy, giving medical assistance to undocumented migrants.

PARTICIPANTS

1918 patients, 998 females and 920 males, with at least one chronic condition (diabetes, cardiovascular diseases (CVDs), mental health disorders) seen over a period of 10 years (2011-2020). Their mean age was 49.2±13 years.

RESULTS

Adherence to medications decreased over 1 year in all patients. This was more evident during the first 2 months of treatment. Patients on only one medication were less adherent than those on more than one medication; at 6 months the percentage of patients with high adherence was 33% vs 57% (p<0.0001) for diabetes, 15% vs 46% (p<0.0001) for mental disorders and 35% vs 59% (p<0.0001) for CVDs. Patients with mental disorders had the lowest adherence: 25% at 6 months and 3% at 1 year. Mental disorders, when present as comorbidities, greatly reduced the probability of being highly adherent: risk ratio (RR) 0.72 (95% CI 0.57 to 0.91; p=0.006) at 3 months, RR 0.77, (95% CI 0.59 to 1.01; p=0.06) at 6 months, RR 0.35 (95% CI 0.13 to 0.94; p=0.04) at 1 year. This was especially evident for patients with CVDs, whose percentage of high adherents decreased to 30% (p=0.0008) at 6 months and to 3% (p=0.01) at 1 year. We also noted that highly adherent patients usually were those most frequently seen by a doctor.

CONCLUSIONS

Interventions to increase medication adherence of undocumented migrants with chronic diseases are necessary, particularly in the first 2 months after beginning treatment. These should be aimed at people-centred care and include more outpatient consultations. Educational interventions should especially be taken into consideration for patients on monotherapy.

Development and Validation of a Machine Learning-Based Model of Mortality Risk in First-Episode Psychosis

Importance

There is an absence of mortality risk assessment tools in first-episode psychosis (FEP) that could enable personalized interventions.

Objective

To examine the feasibility of machine learning (ML) in discerning mortality risk in FEP and to assess whether such risk predictions can inform pharmacotherapy choices.

Design, Setting, and Participants

In this prognostic study, Swedish nationwide cohort data (from July 1, 2006, to December 31, 2021) were harnessed for model development and validation. Finnish cohort data (from January 1, 1998, to December 31, 2017) were used for external validation. Data analyses were completed between December 2022 and December 2023.

Main Outcomes and Measures

Fifty-one nationwide register variables, encompassing demographics and clinical and work-related histories, were subjected to ML to predict future mortality risk. The ML model's performance was evaluated by calculating the area under the receiver operating characteristic curve (AUROC). The comparative effectiveness of pharmacotherapies in patients was assessed and was stratified by the ML model to those with predicted high mortality risk (vs low risk), using the between-individual hazard ratio (HR). The 5 most important variables were then identified and a model was retrained using these variables in the discovery sample.

Results

This study included 24 052 Swedish participants (20 000 in the discovery sample and 4052 in the validation sample) and 1490 Finnish participants (in the validation sample). Swedish participants had a mean (SD) age of 29.1 (8.1) years, 62.1% were men, and 418 died with 2 years. Finnish participants had a mean (SD) age of 29.7 (8.0) years, 61.7% were men, and 31 died within 2 years. The discovery sample achieved an AUROC of 0.71 (95% CI, 0.68-0.74) for 2-year mortality prediction. Using the 5 most important variables (ie, the top 10% [substance use comorbidities, first hospitalization duration due to FEP, male sex, prior somatic hospitalizations, and age]), the final model resulted in an AUROC of 0.70 (95% CI, 0.63-0.76) in the Swedish sample and 0.67 (95% CI, 0.56-0.78) in the Finnish sample. Individuals with predicted high mortality risk had an elevated 15-year risk in the Swedish sample (HR, 3.77 [95% CI, 2.92-4.88]) and an elevated 20-year risk in the Finnish sample (HR, 3.72 [95% CI, 2.67-5.18]). For those with predicted high mortality risk, long-acting injectable antipsychotics (HR, 0.45 [95% CI, 0.23-0.88]) and mood stabilizers (HR, 0.64 [95% CI, 0.46-0.90]) were associated with decreased mortality risk. Conversely, for those predicted to survive, only oral aripiprazole (HR, 0.38 [95% CI, 0.20-0.69]) and risperidone (HR, 0.38 [95% CI, 0.18-0.82]) were associated with decreased mortality risk.

Conclusions and Relevance

In this prognostic study, an ML-based model was developed and validated to predict mortality risk in FEP. These findings may help to develop personalized interventions to mitigate mortality risk in FEP.

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.

A systematic review of the real-world effectiveness and economic and humanistic outcomes of selected oral antipsychotics among patients with schizophrenia in the United States: Updating the evidence and gaps

BACKGROUND

Schizophrenia is a chronic, relapsing, and burdensome psychiatric disorder affecting approximately 0.25%-0.6% of the US population. Oral antipsychotic treatment (OAT) remains the cornerstone for managing schizophrenia. However, nonadherence and high treatment failure lead to increased disease burden and medical spending. Cost-effective management of schizophrenia requires understanding the value of current therapies to facilitate better planning of management policies while addressing unmet needs.

OBJECTIVE

To review existing evidence and gaps regarding real-world effectiveness and economic and humanistic outcomes of OATs, including asenapine, brexpiprazole, cariprazine, iloperidone, lumateperone, lurasidone, olanzapine/samidorphan, paliperidone, and quetiapine.

METHODS

We conducted a literature search using PubMed, American Psychological Association PsycINFO (EBSCOhost), and the Cumulative Index of Nursing and Allied Health Literature from January 2010 to March 2022 as per Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. English-language articles describing adults with schizophrenia receiving at least 1 of the selected OATs and reporting real-world effectiveness, direct or indirect costs, humanistic outcomes, behavioral outcomes, adherence/persistence patterns, or product switching were identified.

RESULTS

We identified 25 studies from a total of 24,190 articles. Real-world effectiveness, cost, and adherence/persistence outcomes were reported for most OATs that were selected. Humanistic outcomes and product switching were reported only for lurasidone. Behavioral outcomes (eg, interpersonal relations and suicide ideation) were not reported for any OAT. The key economic outcomes across studies were incremental cost-effectiveness ratios, cost per quality-adjusted life-years, and health care costs. In studies that compared long-acting injectables (LAIs) with OATs, LAIs had a higher pharmacy and lower medical costs, while total health care cost was similar between LAIs and OATs. Indirect costs associated with presenteeism, absenteeism, or work productivity were not reported for any of the selected OATs. Overall, patients had poor adherence to OATs, ranging between 20% and 61% across studies. Product switching did not impact the all-cause health care costs before and after treatment.

CONCLUSIONS

Our findings showed considerable gaps exist for evidence on behavioral outcomes, humanistic outcomes, medication switching, and adherence/persistence across OATs. Our findings also suggest an unmet need regarding treatment nonadherence and lack of persistence among patients receiving OATs. We identified a need for research addressing OATs' behavioral and humanistic outcomes and evaluating the impact of product switching in adults with schizophrenia in the United States, which could assist clinicians in promoting patient-centered care and help payers understand the total value of new antipsychotic drugs.

Impact of long-acting injectable antipsychotics vs. oral medication on relapses of patients with psychosis and bipolar disorder

Relapse associated with multiple hospital readmissions of patients with chronic and severe mental disorders, such as psychosis and bipolar disorder, is frequently associated with non-adherence to treatment. The primary aim of the study was to compare the effectiveness of long-acting injectable (LAI) treatment, vs. oral medication in reducing readmissions of patients with psychotic or bipolar disorder in a community sample of 164 patients with psychosis and 29 patients with bipolar disorder (n = 193), with poor adherence to oral medication. The mean follow up period was 5.6 years and the number of readmissions were compared for an equal-length period of oral treatment preceding the onset of LAI administration. We observed a significant decrease of 45.2 % in total hospital readmissions after receiving LAIs treatment. The effect was significant both for patients with a pre-LAI treatment history of predominantly voluntary hospitalizations and with predominantly involuntary admissions. In addition, we observed equal effectiveness of first- vs. second-generation LAIs in reducing total hospital readmissions regardless of type of pre-treatment admission history (voluntary vs. involuntary). LAIs appear to be effective in reducing both voluntary and involuntary hospital readmissions in patients with psychosis and bipolar disorder with a history of poor adherence to treatment.

Aripiprazole 2-month ready-to-use 960 mg (Ari 2MRTU): review of its possible role in schizophrenia therapy

Most patients with schizophrenia need life-long treatment. There is therefore a continued need for effective and tolerable treatment options. A 2-monthly LAI formulation of aripiprazole, Aripiprazole 2-Month Ready-to-Use 960 mg (Ari 2MRTU 960) has recently been approved in the US. Here, the possible role in therapy for this new treatment option is discussed in a narrative review. PubMed was searched for literature on long-acting injectables with a focus on patient-reported outcomes and real-world evidence on extended injection intervals (2-3 months). Dopamine D2 partial agonists, one of which is aripiprazole, exhibit favorable tolerability and safety properties. Additionally, there are many advantages in using long-acting injectable formulations such as enhanced treatment persistence and stability of patients as well as reduced rates of relapses, hospitalizations, and death. Some of these advantages become more pronounced with longer injection intervals. Additional advantages of longer injection intervals are more room for non-medication-related communication between healthcare professionals and patients, patient and physician preferences, reduced caregiver burden, and easier transitioning from inpatient to outpatient treatment. Taken together, since aripiprazole may be a good treatment choice for many patients based on its favorable safety and tolerability profile, and given the advantages of LAI treatment over oral treatment and the advantages of reduced dosing frequency, Ari 2MRTU 960 may become an important treatment option for many clinically stable patients with schizophrenia.

Insights into the Mechanism of Action of Antipsychotic Drugs Derived from Animal Models: Standard of Care versus Novel Targets

Therapeutic intervention for schizophrenia relies on blockade of dopamine D2 receptors in the associative striatum; however, there is little evidence for baseline overdrive of the dopamine system. Instead, the dopamine system is in a hyper-responsive state due to excessive drive by the hippocampus. This causes more dopamine neurons to be in a spontaneously active, hyper-responsive state. Antipsychotic drugs alleviate this by causing depolarization block, or excessive depolarization-induced dopamine neuron inactivation. Indeed, both first- and second-generation antipsychotic drugs cause depolarization block in the ventral tegmentum to relieve positive symptoms, whereas first-generation drugs also cause depolarization in the nigrostriatal dopamine system to lead to extrapyramidal side effects. However, by blocking dopamine receptors, these drugs are activating multiple synapses downstream from the proposed site of pathology: the loss of inhibitory influence over the hippocampus. An overactive hippocampus not only drives the dopamine-dependent positive symptoms, but via its projections to the amygdala and the neocortex can also drive negative and cognitive symptoms, respectively. On this basis, a novel class of drugs that can reverse schizophrenia at the site of pathology, i.e., the hippocampal overdrive, could be effective in alleviating all three classes of symptoms of schizophrenia while also being better tolerated.

Use of Long-Acting Injectable Antipsychotics in a Clinical Sample of Community-Dwelling Patients with Schizophrenia-Spectrum Disorders in Rural Greece

Data on the use of long-acting injectable antipsychotics (LAIs) in rural community mental healthcare settings are scarce. This study aimed to investigate the prescription patterns of LAIs in a clinical sample of patients with schizophrenia-spectrum disorders in rural Greece. All patients with schizophrenia-spectrum disorders who regularly attend the Mobile Mental Health Unit of the prefectures of Ioannina and Thesprotia (MMHU I-T) in northwestern Greece were included in the study. The sample consists of 87 patients (59 males and 28 females) with a mean age of 54.4 years and a mean illness duration of 28 years. Most patients (72.4%) received antipsychotic monotherapy, and nearly 30% received an LAI formulation, mostly a second-generation LAI (20 of 26 patients, 76.9%). The treatment regimen comprised benzodiazepines in one-third of the patients and antidepressants in one-quarter. There was no statistically significant association between treatment regimen and the clinical and demographic variables studied, except for biological sex (female). The percentage of patients treated with LAIs in this study was almost three times higher than the rate previously reported in Greece and is higher than the rates reported in other countries. Patients with schizophrenia-spectrum disorders in rural Greece may have adequate access to innovative treatment with second-generation LAIs. Further research is needed to demonstrate the cost-effectiveness of LAI treatment in rural communities and to elucidate the factors associated with such treatment.

Long-acting antipsychotics in the treatment of schizophrenia: opportunities and challenges

INTRODUCTION

Maintenance antipsychotic treatment improves multiple outcomes in people with schizophrenia. These benefits are challenged by medication nonadherence, which is a common occurrence. Long-acting injectable antipsychotic (LAI) formulations were developed to reduce nonadherence and thereby improve outcomes. This narrative review is based on a PubMed search (January 2000 - August 2022) for studies on LAI antipsychotics.

AREAS COVERED

Opportunities and challenges associated with LAIs are reviewed. Advantages, compared to oral antipsychotics (OAs), include improved adherence, reduced relapse and hospitalization risk, delayed and lower relapse risk after stopping treatment, and the ability to differentiate true treatment resistance from 'pseudo'-resistance. Additionally, LAIs are associated with lower all-cause mortality than OAs. LAIs are under-used in many services, partly reflecting negative attitudes, misconceptions, and lack of knowledge among clinicians, patients, and carers. Practical barriers to LAI use include acquisition costs and inadequate service structures to administer/monitor LAI treatment.

EXPERT OPINION

The education and engagement of clinicians, patients and caregivers can assist more informed decision-making regarding LAIs. Future research regarding LAIs should encompass multiple complementary designs, focus on functionality and recovery outcomes, and include groups at high risk of relapse, including those with comorbid substance use disorders and early in the course of schizophrenia.

Pharmacokinetics and pharmacogenomics of clozapine in an ancestrally diverse sample: a longitudinal analysis and genome-wide association study using UK clinical monitoring data

BACKGROUND

The antipsychotic, clozapine, is the only licensed drug against the treatment-resistant symptoms that affect 20-30% of people with schizophrenia. Clozapine is markedly underprescribed, partly because of concerns about its narrow therapeutic range and adverse drug reaction profile. Both concerns are linked to drug metabolism, which varies across populations globally and is partly genetically determined. Our study aimed to use a cross-ancestry genome-wide association study (GWAS) design to investigate variations in clozapine metabolism within and between genetically inferred ancestral backgrounds, to discover genomic associations to clozapine plasma concentrations, and to assess the effects of pharmacogenomic predictors across different ancestries.

METHODS

In this GWAS, we analysed data from the UK Zaponex Treatment Access System clozapine monitoring service as part of the CLOZUK study. We included all available individuals with clozapine pharmacokinetic assays requested by their clinicians. We excluded people younger than 18 years, or whose records contained clerical errors, or with blood drawn 6-24 h after dose, a clozapine or norclozapine concentration less than 50 ng/mL, a clozapine concentration of more than 2000 ng/mL, a clozapine-to-norclozapine ratio outside of the 0·5-3·0 interval, or a clozapine dose of more than 900 mg/day. Using genomic information, we identified five biogeographical ancestries: European, sub-Saharan African, north African, southwest Asian, and east Asian. We did pharmacokinetic modelling, a GWAS, and a polygenic risk score association analysis using longitudinal regression analysis with three primary outcome variables: two metabolite plasma concentrations (clozapine and norclozapine) and the clozapine-to-norclozapine ratio.

FINDINGS

19 096 pharmacokinetic assays were available for 4760 individuals in the CLOZUK study. After data quality control, 4495 individuals (3268 [72·7%] male and 1227 [27·3%] female; mean age 42·19 years [range 18-85]) linked to 16 068 assays were included in this study. We found a faster average clozapine metabolism in people of sub-Saharan African ancestry than in those of European ancestry. By contrast, individuals with east Asian or southwest Asian ancestry were more likely to be slow clozapine metabolisers than those with European ancestry. Eight pharmacogenomic loci were identified in the GWAS, seven with significant effects in non-European groups. Polygenic scores generated from these loci were associated with clozapine outcome variables in the whole sample and within individual ancestries; the maximum variance explained was 7·26% for the metabolic ratio.

INTERPRETATION

Longitudinal cross-ancestry GWAS can discover pharmacogenomic markers of clozapine metabolism that, individually or as polygenic scores, have consistent effects across ancestries. Our findings suggest that ancestral differences in clozapine metabolism could be considered for optimising clozapine prescription protocols for diverse populations.

FUNDING

UK Academy of Medical Sciences, UK Medical Research Council, and European Commission.

Therapeutic Adherence of People with Mental Disorders: An Evolutionary Concept Analysis

Patient therapeutic adherence lies at the core of mental health care. Health Care professionals and organizations play a major role in promoting adherence among people with mental disorders. However, defining therapeutic adherence remains complex. We used Rodgers' evolutionary concept analysis to explore the concept of therapeutic adherence in the context of mental health. We conducted a systematic literature search on Medline/PubMed and CINAHL for works published between January 2012 and December 2022. The concept analysis showed that major attributes of therapeutic adherence include patient, microsystem and meso/exosystem-level factors. Antecedents are those related to patients, such as their background, beliefs and attitudes, and acceptance of mental illness-and those related to patient-HCP therapeutic engagement. Lastly, three different consequences of the concept emerged: an improvement in clinical and social outcomes, commitment to treatment, and the quality of healthcare delivery. We discuss an operational definition that emerged from the concept analysis approach. However, considering the concept has undergone evolutionary changes, further research related to patient adherence experiences in an ecological stance is needed.

Antipsychotic prescribing practices in real-life (APPREAL study): Findings from the French National Healthcare System Database (2007-2017)

BACKGROUND

Antipsychotics are used in a large variety of psychiatric and neurological disorders; investigating their use in real life is important to understand national prescribing practices, as well as to determine the levels of patient adherence.

METHODS

Using a 1/97e random sample (General Sample of Beneficiaries, EGB) of the French health insurance reimbursement database, we conducted a historical cohort study on the 2007-2017 period. The aim was to describe the sociodemographic characteristics of patients, the types of antipsychotics dispensed, the types of prescribers, the mean doses and average durations of treatment, the co-dispensed medications, and the levels of adherence to treatment. To exclude punctual uses of antipsychotics, we selected only patients with a continuous dispensing of the same antipsychotic over at least 3 months.

RESULTS

In total, 13,799 subjects (1.66% of the EGB sample) were included (56.0% females; mean age 55.8 ± 19.4 years). Risperidone (19.3%), cyamemazine (18.7%), olanzapine (11.9%), tiapride (8.8%), and haloperidol (7.5%) were the five most prescribed antipsychotics. 44.9% of prescriptions were written by general practitioners, 34.1% by hospital practitioners, and 18.4% by private-practice psychiatrists. On average, the mean dispensed doses were relatively low, but the variation range was large. Long-acting forms were used in 5.4% of the sample, and clozapine in 1.3%. 34.2% of patients received more than one antipsychotic, and almost 15% were prescribed at least three concomitant antipsychotics. Paliperidone and clozapine were associated with the highest levels of adherence, and risperidone and haloperidol with the lowest ones.

CONCLUSION

An important heterogeneity of antipsychotic prescribing practices was observed in France. The rate of use of long-acting antipsychotics was low, whereas multiple antipsychotic prescriptions were frequent.