New living evidence resource of human and non-human studies for early intervention and research prioritisation in anxiety, depression and psychosis

Muscarinic receptor agonists and positive allosteric modulators in animal models of psychosis: protocol for a systematic review and meta-analysis

Background

Muscarinic receptor agonism and positive allosteric modulation is a promising mechanism of action for treating psychosis, not present in most D2R-blocking antipsychotics. Xanomeline, an M1/M4-preferring agonist, has shown efficacy in late-stage clinical trials, with more compounds being investigated. Therefore, we aim to synthesize evidence on the preclinical efficacy of muscarinic receptor agonists and positive allosteric modulators in animal models of psychosis to provide unique insights and evidence-based information to guide drug development.

Methods

We plan a systematic review and meta-analysis of in vivo animal studies comparing muscarinic receptor agonists or positive allosteric modulators with control conditions and existing D2R-blocking antipsychotics in animals subjected to any method that induces behavioural changes of relevance for psychosis. We will identify eligible studies by searching multiple electronic databases. At least two independent reviewers will conduct the study selection and data extraction using prespecified forms and assess the risk of bias with the SYRCLE's tool. Our primary outcomes include locomotor activity and prepulse inhibition measured with standardized mean differences. We will examine other behavioural readouts of relevance for psychosis as secondary outcomes, such as social interaction and cognitive function. We will synthesize the data using multi-level meta-analysis with a predefined random-effects structure, considering the non-independence of the data. In meta-regressions we will explore potential sources of heterogeneity from a predefined list of characteristics of the animal population, model, and intervention. We will assess the confidence in the evidence considering a self-developed instrument thatconsiders the internal and external validity of the evidence.

Protocol registration

PROSPERO-ID: CRD42024520914.

Triangulating evidence from the GALENOS living systematic review on trace amine-associated receptor 1 (TAAR1) agonists in psychosis

BACKGROUND

Trace amine-associated receptor 1 (TAAR1) agonists offer a new approach, but there is uncertainty regarding their effects, exact mechanism of action and potential role in treating psychosis.

AIMS

To evaluate the available evidence on TAAR1 agonists in psychosis, using triangulation of the output of living systematic reviews (LSRs) of animal and human studies, and provide recommendations for future research prioritisation.

METHOD

This study is part of GALENOS (Global Alliance for Living Evidence on aNxiety, depressiOn and pSychosis). In the triangulation process, a multidisciplinary group of experts, including those with lived experience, met and appraised the first co-produced living systematic reviews from GALENOS, on TAAR1 agonists.

RESULTS

The animal data suggested a potential antipsychotic effect, as TAAR1 agonists reduced locomotor activity induced by pro-psychotic drug treatment. Human studies showed few differences for ulotaront and ralmitaront compared with placebo in improving overall symptoms in adults with acute schizophrenia (four studies, n = 1291 participants, standardised mean difference (SMD) 0.15, 95% CI -0.05 to 0.34). Large placebo responses were seen in ulotaront phase three trials. Ralmitaront was less efficacious than risperidone (one study, n = 156 participants, SMD = -0.53, 95% CI -0.86 to -0.20). The side-effect profile of TAAR1 agonists was favourable compared with existing antipsychotics. Priorities for future studies included (a) using different animal models of psychosis with greater translational validity; (b) animal and human studies with wider outcomes including cognitive and affective symptoms and (c) mechanistic studies and investigations of other potential applications, such as adjunctive treatments and long-term outcomes. Recommendations for future iterations of the LSRs included (a) meta-analysis of individual human participant data, (b) including studies that used different methodologies and (c) assessing other disorders and symptoms.

CONCLUSIONS

This co-produced, international triangulation examined the available evidence and developed recommendations for future research and clinical applications for TAAR1 agonists in psychosis. Broader challenges included difficulties in assessing the risk of bias, reproducibility, translation and interpretability of animal models to clinical outcomes, and a lack of individual and clinical characteristics in the human data. The research will inform a separate, independent prioritisation process, led by lived experience experts, to prioritise directions for future research.

Towards an ontology of mental health: Protocol for developing an ontology to structure and integrate evidence regarding anxiety, depression and psychosis

Background

Research about anxiety, depression and psychosis and their treatments is often reported using inconsistent language, and different aspects of the overall research may be conducted in separate silos. This leads to challenges in evidence synthesis and slows down the development of more effective interventions to prevent and treat these conditions. To address these challenges, the Global Alliance for Living Evidence on aNxiety, depressiOn and pSychosis (GALENOS) Project is conducting a series of living systematic reviews about anxiety, depression and psychosis. An ontology (a classification and specification framework) for the domain of mental health is being created to organise and synthesise evidence within these reviews and present them in a structured online data repository.

Aim

This study aims to develop an ontology of mental health that includes entities with clear labels and definitions to describe and synthesise evidence about mental health, focusing on anxiety, depression and psychosis.

Methods

We will develop and apply the GALENOS Mental Health Ontology through eight steps: (1) defining the ontology's scope; (2) identifying, labelling and defining the ontology's entities for the GALENOS living systematic reviews; (3) structuring the ontology's upper level (4) refining entities via iterative stakeholder consultations regarding the ontology's clarity and scope; (5) formally specifying the relationships between entities in the Mental Health Ontology; (6) making the ontology machine-readable and available online; (7) integrating the ontology into the data repository; and (8) exploring the ontology-structured repository's usability.

Conclusion and discussion

The Mental Health Ontology supports the formal representation of complex upper-level entities within mental health and their relationships. It will enable more explicit and precise communication and evidence synthesis about anxiety, depression and psychosis across the GALENOS Project's living systematic reviews. By being computer readable, the ontology can also be harnessed within algorithms that support automated categorising, linking, retrieving and synthesising evidence.

Public involvement in an aggregate and individual participant data meta-analysis of mindfulness-based programmes for mental health promotion

BACKGROUND

Involving the public in evidence synthesis research is challenging due to the highly analytic nature of the projects, so it is important that involvement processes are documented, reflected upon, and shared to devise best practices. There is a literature gap on the involvement of the public in individual participant data meta-analyses, particularly in public health projects. We aimed to document and reflect on our collective experiences of involving and being involved as public stakeholders at all stages of a systematic review and individual participant data meta-analysis project.

METHODS

We formed a stakeholder group made of four members of the public at the beginning of our evidence synthesis project comprising a systematic review, an aggregate data meta-analysis, and an individual participant data meta-analysis of mindfulness-based programmes for mental health promotion in non-clinical adults. Following each group meeting, members and participating researchers completed written reflections; one group member collected and collated these. At the end of the project, a reflective writing workshop was held before all members completed their final reflections. Everyone completed an adapted, open-ended questionnaire which asked about what did and did not work well, the overall experience, what could be improved, and the felt impact the stakeholder group had on the research.

RESULTS

Overall, the stakeholders and researchers reported a positive experience of working together. Positives from the stakeholders' point of view included learning new skills, experiencing research, and making new friends. For the researchers, stakeholders helped them focus on what matters to the public and were reinvigorating research partners. The challenges stakeholders experienced included having long gaps between meetings and feeling overwhelmed. The researchers found it challenging to strike the balance between asking stakeholders to be involved and for them to learn research-related skills without overburdening them and making sure that the learning was engaging. When looking back at their experience, stakeholders described seeing their impact on the project in hindsight but that this was not felt while the project was being carried out.

CONCLUSION

Successfully involving the public in complex evidence synthesis projects is possible and valuable from the points of view of the researchers and the stakeholders. However, it requires a significant time, skill, and resource investment that needs to be factored in from project inception. Further guidance and stakeholder training materials would be helpful. Specific suggestions are provided.

Trace amine-associated receptor 1 (TAAR1) agonism for psychosis: a living systematic review and meta-analysis of human and non-human data

Background

Trace amine-associated receptor 1 (TAAR1) agonism shows promise for treating psychosis, prompting us to synthesise data from human and non-human studies.

Methods

We co-produced a living systematic review of controlled studies examining TAAR1 agonists in individuals (with or without psychosis/schizophrenia) and relevant animal models. Two independent reviewers identified studies in multiple electronic databases (until 17.11.2023), extracted data, and assessed risk of bias. Primary outcomes were standardised mean differences (SMD) for overall symptoms in human studies and hyperlocomotion in animal models. We also examined adverse events and neurotransmitter signalling. We synthesised data with random-effects meta-analyses.

Results

Nine randomised trials provided data for two TAAR1 agonists (ulotaront and ralmitaront), and 15 animal studies for 10 TAAR1 agonists. Ulotaront and ralmitaront demonstrated few differences compared to placebo in improving overall symptoms in adults with acute schizophrenia (N=4 studies, n=1291 participants; SMD=0.15, 95%CI: -0.05, 0.34), and ralmitaront was less efficacious than risperidone (N=1, n=156, SMD=-0.53, 95%CI: -0.86, -0.20). Large placebo response was observed in ulotaront phase-III trials. Limited evidence suggested a relatively benign side-effect profile for TAAR1 agonists, although nausea and sedation were common after a single dose of ulotaront. In animal studies, TAAR1 agonists improved hyperlocomotion compared to control (N=13 studies, k=41 experiments, SMD=1.01, 95%CI: 0.74, 1.27), but seemed less efficacious compared to dopamine D 2 receptor antagonists (N=4, k=7, SMD=-0.62, 95%CI: -1.32, 0.08). Limited human and animal data indicated that TAAR1 agonists may regulate presynaptic dopaminergic signalling.

Conclusions

TAAR1 agonists may be less efficacious than dopamine D 2 receptor antagonists already licensed for schizophrenia. The results are preliminary due to the limited number of drugs examined, lack of longer-term data, publication bias, and assay sensitivity concerns in trials associated with large placebo response. Considering their unique mechanism of action, relatively benign side-effect profile and ongoing drug development, further research is warranted.

Registration

PROSPERO-ID: CRD42023451628.

Assessing the Impact of Evidence-Based Mental Health Guidance During the COVID-19 Pandemic: Systematic Review and Qualitative Evaluation

BACKGROUND

During the COVID-19 pandemic, the Oxford Precision Psychiatry Lab (OxPPL) developed open-access web-based summaries of mental health care guidelines (OxPPL guidance) in key areas such as digital approaches and telepsychiatry, suicide and self-harm, domestic violence and abuse, perinatal care, and vaccine hesitancy and prioritization in the context of mental illness, to inform timely clinical decision-making.

OBJECTIVE

This study aimed to evaluate the practice of creating evidence-based health guidelines during health emergencies using the OxPPL guidance as an example. An international network of clinical sites and colleagues (in Australia, New Zealand, and the United Kingdom) including clinicians, researchers, and experts by experience aimed to (1) evaluate the clinical impact of the OxPPL guidance, as an example of an evidence-based summary of guidelines; (2) review the literature for other evidence-based summaries of COVID-19 guidelines regarding mental health care; and (3) produce a framework for response to future global health emergencies.

METHODS

The impact and clinical utility of the OxPPL guidance were assessed using clinicians' feedback via an international survey and focus groups. A systematic review (protocol registered on Open Science Framework) identified summaries or syntheses of guidelines for mental health care during and after the COVID-19 pandemic and assessed the accuracy of the methods used in the OxPPL guidance by identifying any resources that the guidance had not included.

RESULTS

Overall, 80.2% (146/182) of the clinicians agreed or strongly agreed that the OxPPL guidance answered important clinical questions, 73.1% (133/182) stated that the guidance was relevant to their service, 59.3% (108/182) said that the guidelines had or would have a positive impact on their clinical practice, 42.9% (78/182) that they had shared or would share the guidance, and 80.2% (146/182) stated that the methodology could be used during future health crises. The focus groups found that the combination of evidence-based knowledge, clinical viewpoint, and visibility was crucial for clinical implementation. The systematic review identified 2543 records, of which 2 syntheses of guidelines met all the inclusion criteria, but only 1 (the OxPPL guidance) used evidence-based methodology. The review showed that the OxPPL guidance had included the majority of eligible guidelines, but 6 were identified that had not been included.

CONCLUSIONS

The study identified an unmet need for web-based, evidence-based mental health care guidance during the COVID-19 pandemic. The OxPPL guidance was evaluated by clinicians as having a real-world clinical impact. Robust evidence-based methodology and expertise in mental health are necessary, but easy accessibility is also needed, and digital technology can materially help. Further health emergencies are inevitable and now is the ideal time to prepare, including addressing the training needs of clinicians, patients, and carers, especially in areas such as telepsychiatry and digital mental health. For future planning, guidance should be widely disseminated on an international platform, with allocated resources to support adaptive updates.

Trace amine-associated receptor 1 (TAAR1) agonists for psychosis: protocol for a living systematic review and meta-analysis of human and non-human studies

BACKGROUND

There is an urgent need to develop more effective and safer antipsychotics beyond dopamine 2 receptor antagonists. An emerging and promising approach is TAAR1 agonism. Therefore, we will conduct a living systematic review and meta-analysis to synthesize and triangulate the evidence from preclinical animal experiments and clinical studies on the efficacy, safety, and underlying mechanism of action of TAAR1 agonism for psychosis.

METHODS

Independent searches will be conducted in multiple electronic databases to identify clinical and animal experimental studies comparing TAAR1 agonists with licensed antipsychotics or other control conditions in individuals with psychosis or animal models for psychosis, respectively. The primary outcomes will be overall psychotic symptoms and their behavioural proxies in animals. Secondary outcomes will include side effects and neurobiological measures. Two independent reviewers will conduct study selection, data extraction using predefined forms, and risk of bias assessment using suitable tools based on the study design. Ontologies will be developed to facilitate study identification and data extraction. Data from clinical and animal studies will be synthesized separately using random-effects meta-analysis if appropriate, or synthesis without meta-analysis. Study characteristics will be investigated as potential sources of heterogeneity. Confidence in the evidence for each outcome and source of evidence will be evaluated, considering the summary of the association, potential concerns regarding internal and external validity, and reporting biases. When multiple sources of evidence are available for an outcome, an overall conclusion will be drawn in a triangulation meeting involving a multidisciplinary team of experts. We plan trimonthly updates of the review, and any modifications in the protocol will be documented. The review will be co-produced by multiple stakeholders aiming to produce impactful and relevant results and bridge the gap between preclinical and clinical research on psychosis.

PROTOCOL REGISTRATION

PROSPERO-ID: CRD42023451628.