How do we select an antipsychotic for those with schizophrenia?

A Comprehensive Review of Schizophrenia and Antipsychotic Metabolism as a Predictor of Treatment Response

Some patients with schizophrenia fail to respond to standard antipsychotics and are considered treatment-resistant. In these cases, clozapine is the only antipsychotic with proven efficacy, but its use is complicated by severe adverse effects, complex monitoring requirements, and non-response. Variation within the CYP450 enzymes CYP1A2, CYP2D6, CYP3A4, and CYP2C19 has been linked to the differential metabolism of antipsychotics. Testing for CYP450 single nucleotide polymorphisms may be a useful predictor of treatment resistance and could inform pharmacogenetic recommendations to identify potential treatment non-responders. Nonetheless, it remains uncertain whether differential antipsychotic metabolism is directly related to treatment efficacy. This comprehensive narrative review endeavours to delve into the molecular and genetic basis of schizophrenia, and discuss the current treatments available. In particular, we aim to examine the aetiology of treatment resistance in schizophrenia through available literature and discuss current challenges within the field.

The New Horizon of Antipsychotics beyond the Classic Dopaminergic Hypothesis-The Case of the Xanomeline-Trospium Combination: A Systematic Review

Although the dopamine hypothesis of schizophrenia explains the effects of all the available antipsychotics in clinical use, there is an increasing need for developing new drugs for the treatment of the positive, negative, and cognitive symptoms of chronic psychoses. Xanomeline-trospium (KarXT) is a drug combination that is based on the essential role played by acetylcholine in the regulation of cognitive processes and the interactions between this neurotransmitter and other signaling pathways in the central nervous system, with a potential role in the onset of schizophrenia, Alzheimer's disease, and substance use disorders. A systematic literature review that included four electronic databases (PubMed, Cochrane, Clarivate/Web of Science, and Google Scholar) and the US National Library of Medicine database for clinical trials detected twenty-one sources referring to fourteen studies focused on KarXT, out of which only four have available results. Based on the results of these trials, the short-term efficacy and tolerability of xanomeline-trospium are good, but more data are needed before this drug combination may be recommended for clinical use. However, on a theoretical level, the exploration of KarXT is useful for increasing the interest of researchers in finding new, non-dopaminergic, antipsychotics that could be used either as monotherapy or as add-on drugs.

A Hybrid Type 1 trial of a multi-component mHealth intervention to improve post-hospital transitions of care for patients with serious mental illness: Study protocol

BACKGROUND

The transition from acute (e.g., psychiatric hospitalization) to outpatient care is associated with increased risk for rehospitalization, treatment disengagement, and suicide among people with serious mental illness (SMI). Mobile interventions (i.e., mHealth) have the potential to increase monitoring and improve coping post-acute care for this population. This protocol paper describes a Hybrid Type 1 effectiveness-implementation study, in which a randomized controlled trial will be conducted to determine the effectiveness of a multi-component mHealth intervention (tFOCUS) for improving outcomes for adults with SMI transitioning from acute to outpatient care.

METHODS

Adults meeting criteria for schizophrenia-spectrum or major mood disorders (n = 180) will be recruited from a psychiatric hospital and randomized to treatment-as-usual (TAU) plus standard discharge planning and aftercare (CHECK-IN) or TAU plus tFOCUS. tFOCUS is a 12-week intervention, consisting of: (a) a patient-facing mHealth smartphone app with daily self-assessment prompts and targeted coping strategies; (b) a clinician-facing web dashboard; and, (c) mHealth aftercare advisors, who will conduct brief post-hospital clinical calls with patients (e.g., safety concerns, treatment engagement) and encourage app use. Follow-ups will be conducted at 6-, 12-, and 24-weeks post-discharge to assess primary and secondary outcomes, as well as target mechanisms. We also will assess barriers and facilitators to future implementation of tFOCUS via qualitative interviews of stakeholders and input from a Community Advisory Board throughout the project.

CONCLUSIONS

Information gathered during this project, in combination with successful study outcomes, will inform a potential tFOCUS intervention scale-up across a range of psychiatric hospitals and healthcare systems.

CLINICALTRIALS

govregistration: NCT05703412.

Efficacy and Safety Profiles of Antipsychotic Drugs as Viewed by Psychiatrists: A Comparative Analysis of Cariprazine and Risperidone

BACKGROUND

Physicians hold the belief that the treatment outcomes and the treatment strategy they eventually adopt is largely determined by the differences in medications. Despite numerous studies focusing on the decision-making processes of psychiatrists, including the choice of antipsychotics when prescribing pharmacotherapy, the impact of therapeutic drug profiling on physicians' decision-making remains poorly comprehended.

AIM

The aim of this study is to assess the quantitative differences in perceptions of antipsychotics by psychiatrists using cariprazine and risperidone as examples.

METHODS

A total of 79 psychiatrists were interviewed anonymously in St. Petersburg, Russia. The physicians documented the clinical advantages they perceived drugs to possess relative to one another, following a predetermined principle: A B, A=B, A B (2-AC protocol). The comparison is based on eleven parameters that assess the effectiveness and safety of cariprazine or risperidone. It has been hypothesized that the pattern of responses (qualitative difference) and the degree of preference for each drug (quantitative difference) may not align with the data in the original meta-analyses.

RESULTS

The perception parameter exhibited a greater difference than anticipated (δ - 0.889), while the threshold for differentiating between the drugs was lower (τ - 1.001). The response pattern only aligned with theory by 44.37%. The dispersion of responses was associated with the length of work experience.

CONCLUSION

The perceived difference between the drugs significantly deviates from the theoretical data, both in terms of strength of perception and pattern (quantitative and qualitative differences).

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.

Dosing antipsychotics in special populations of patients with schizophrenia: severe psychotic agitation, first psychotic episode and elderly patients

Antipsychotic (AP) dosing is well established in nonelderly patients with acute exacerbations of schizophrenia, but not in special populations.This review describes the AP dosing procedures that have been used in clinical studies for acute psychotic agitation, a first episode of psychosis (FEP), and elderly patients. AP dosing data was extracted from the databases of drug regulatory authorities, and from clinical studies available in the medical literature. In acute psychotic agitation, intramuscular and oral APs are frequently prescribed in higher doses than those that saturate D2 receptors. Supersaturating doses of APs should be avoided due to an increased risk of adverse effects. In FEP, many studies showed efficacy of low doses of APs. Studies with risperidone and haloperidol suggested a dose reduction of approximately one third. Titration with a lower starting dose is recommended in elderly patients, due to possible decreases in pharmacokinetic clearance, and due to the risk of concomitant diseases and drug interactions. Exposure to some APs has been associated with QTc prolongation and arrhythmias, and a small but significant increase in the risk of stroke and mortality with APs has been seen, particularly in older people with dementia-related psychosis.

Barriers and Enablers to Shared Decision Making in Psychiatric Medication Management: A Qualitative Investigation of Clinician and Service Users' Views

Shared decisionmaking (SDM) is a recommended health communication approach in mental health settings. Yet, implementation of SDM in psychiatric consultations discussing medication management is challenging. Insufficient attention has been given to examine the views of both clinicians and service users together about the experiences of SDM in psychiatric medication management. The purpose of this paper is to examine the views of service users, community psychiatric nurses, and psychiatrists about enablers and barriers of SDM. A thematic analysis of 30 semi structured interviews with service users, psychiatrists, and community psychiatric nurses, in a community mental health team in the UK, was conducted. A service user advisory group was involved in all phases of the research cycle, including data collection, analysis, and dissemination. The results offer a detailed contextualized account of how medication decisions are made. For psychiatrists and service user participants SDM is seen as a way of enhancing service users' engagement in and control over treatment decisions. While psychiatrists value the transactional benefits of SDM, service user participants and psychiatric nurses conceptualize SDM as a long-term endeavor embedded within therapeutic partnerships. For service users these partnerships mitigate acknowledged problems of feeling unable to be fully involved during times of crisis. This study identified a range of barriers and facilitators to SDM concerning psychiatric medications from the lived experience of service users and the professional experience of clinicians. Furthermore, it indicates new potential intervention points to support SDM in psychiatric medication decisions.