Experimental Medicine Approach Research Articles

Developing KCNQ (Kv7) Type Channel Openers for Anhedonia and Depression: An Experimental Medicine Approach

Developing KCNQ (Kv7) Type Channel Openers for Anhedonia and Depression: An Experimental Medicine Approach

Single-cell insights into immune dysregulation in rheumatoid arthritis flare versus drug-free remission.

Immune-mediated inflammatory diseases (IMIDs) are typically characterised by relapsing and remitting flares of inflammation. However, the unpredictability of disease flares impedes their study. Addressing this critical knowledge gap, we use the experimental medicine approach of immunomodulatory drug withdrawal in rheumatoid arthritis (RA) remission to synchronise flare processes allowing detailed characterisation. Exploratory mass cytometry analyses reveal three circulating cellular subsets heralding the onset of arthritis flare - CD45RO+PD1hi CD4+ and CD8+ T cells, and CD27+CD86+CD21- B cells - further characterised by single-cell sequencing. Distinct lymphocyte subsets including cytotoxic and exhausted CD4+ memory T cells, memory CD8+CXCR5+ T cells, and IGHA1+ plasma cells are primed for activation in flare patients. Regulatory memory CD4+ T cells (Treg cells) increase at flare onset, but with dysfunctional regulatory marker expression compared to drug-free remission. Significant clonal expansion is observed in T cells, but not B cells, after drug cessation; this is widespread throughout memory CD8+ T cell subsets but limited to the granzyme-expressing cytotoxic subset within CD4+ memory T cells. Based on our observations, we suggest a model of immune dysregulation for understanding RA flare, with potential for further translational research towards novel avenues for its treatment and prevention.

Examining the Malleability of Negative Views of Aging, Self-Efficacy Beliefs, and Behavioral Intentions in Middle-Aged and Older Adults.

This study examined the malleability of a tripartite cluster of purported mechanistic variables targeted in a 4-week intervention program designed to improve adults' engagement in physical activity. The targeted cluster of purported mechanisms consisted of negative views of aging (NVOA), self-efficacy beliefs, and behavioral intentions. A randomized single-blind control group design was used to implement the AgingPLUS program in a sample of middle-aged and older adults (N = 335; Mage = 60.1 years; SDage = 8.3 years; age range 45-75 years). Using an intention-to-treat approach and analyses of covariance adjusting for participants' baseline scores, findings showed significant improvements in the purported mechanistic variables both at the immediate (Week 4) and delayed posttest (Week 8) in the treatment group but not in the control group. These improvements were for the most part maintained until 8-month postrandomization, although to a smaller extent. Specifically, participants in the AgingPLUS group showed significant improvements in NVOA, self-efficacy beliefs, and behavioral intentions compared to the Health Education control group. Standardized effect sizes for statistically significant effects were variable and ranged from small (d = -0.23) to large (d = 0.80). Effect sizes showed some decay of the intervention at the 8-month posttest. Taken together, the findings supported the efficacy of the AgingPLUS program and showed that variables representing the purported mechanisms of the intervention were significantly moved in a positive direction. In doing so, the AgingPLUS program met a major requirement of the experimental medicine approach to behavior change interventions. NCT0329948.

The Serotonin 1A (5-HT1A) Receptor as a Pharmacological Target in Depression.

Clinical depression is a common, debilitating and heterogenous disorder. Existing treatments for depression are inadequate for a significant minority of patients and new approaches are urgently needed. A wealth of evidence implicates the serotonin1A (5-HT1A) receptor in the pathophysiology of depression. Stimulation of the 5-HT1A receptor is an existing therapeutic target for treating depression and anxiety, using drugs such as buspirone and tandospirone. However, activation of 5-HT1A raphe autoreceptors has also been suggested to be responsible for the delay in the therapeutic action of conventional antidepressants such as selective serotonin reuptake inhibitors (SSRIs). This narrative review provides a brief overview of the 5-HT1A receptor, the evidence implicating it in depression and inthe effects of conventional antidepressant treatment. We highlight that pre- and post-synaptic 5-HT1A receptors may have divergent roles in the pathophysiology and treatment of depression. To date, developing this understanding to progress therapeutic discovery has been limited, partly due to a paucity of specific pharmacological probes suitable for use in humans. The development of 5-HT1A 'biased agonism', using compounds such as NLX-101, offers the opportunity to further elucidate the roles of pre- and post-synaptic 5-HT1A receptors. We describe how experimental medicine approaches can be helpful in profiling the effectsof 5-HT1A receptor modulation on the different clinical domains of depression, and outline some potential neurocognitive models that could be used to test the effects of 5-HT1A biased agonists.

The NIH Science of Behavior Change Program: Looking Toward the Future

The National Institutes of Health established the Science of Behavior Change (SOBC) program to promote basic research on the initiation, personalization, and maintenance of health behavior change. The SOBC Resource and Coordinating Center now leads and supports activities to maximize the creativity, productivity, scientific rigor, and dissemination of the experimental medicine approach and experimental design resources. Here, we highlight those resources, including the Checklist for Investigating Mechanisms in Behavior-change Research (CLIMBR) guidelines introduced in this special section. We describe the ways in which SOBC can be applied across a range of domains and contexts, and end by considering ways to extend SOBC’s perspective and reach, so as to best promote behavior change linked with health, quality of life, and well-being.

An Experimental Therapeutics Focus on Novel Mechanistic Targets in Cognitive Behavioral Treatments: Introduction to the Special Section

This article introduces the special section, “An Experimental Therapeutics Focus on Novel Mechanistic Targets in Cognitive Behavioral Treatments.” The purpose of this special section is to highlight research that follows the recommended Science of Behavior Change (SOBC) developmental progression for an experimental medicine approach to identifying and testing mechanisms of behavior change. Emphasis was placed on the earlier stage “pipeline” of investigations of novel mechanisms for behavior change: mechanisms that are undergoing the initial stages of validation. In this series, seven empirical articles are presented and are followed by an article detailing a checklist for reporting mechanistic research studies in order to improve communication of findings in the field. The final article in this series discusses the history, current status, and future directions for the SOBC approach to mechanistic science as viewed by National Institute of Health program officials.

An Experimental Therapeutics Approach to the Development of a Novel Computerized Treatment Targeting Error-Related Brain Activity in Young Children

In the current study, we utilize an experimental medicine approach to examine the extent to which a single-session, computerized intervention impacts a transdiagnostic neural marker of risk (i.e., the error-related negativity [ERN]) in 70 children between the ages of 6 and 9 years. The ERN is a deflection in the event-related potential occurring after an individual makes a mistake on a lab-based task and has been shown to be transdiagnostically associated with a variety of anxiety disorders (e.g., social anxiety, generalized anxiety), obsessive-compulsive disorder, and depressive disorders in over 60 studies to date. Building on these findings, work has been done to link an increased ERN to negative reactions to, and avoidance of, making mistakes (i.e., error sensitivity). In the current study, we capitalize on this previous work by examining the extent to which a single-session, computerized intervention may engage the target of “error sensitivity” (measured by the ERN, as well as self-report of error sensitivity). We examine the convergence of multiple measures of the construct of “error sensitivity” (i.e., child self-report, parent report on child, and child electroencephalogram [EEG]). We also examine relationships between these three measures of “error sensitivity” and child anxiety symptoms. Overall, results suggested that treatment condition predicted changes in self-reported error sensitivity but not changes in ERN. Based on the lack of previous work in this area, we view this study as a novel, preliminary, first step toward using an experimental medicine approach to examine our ability to engage the target of the ERN (i.e., error sensitivity) early in development.

Initial assessment of the feasibility and efficacy of a scalable digital CBT for generalized anxiety and associated health behaviors in a cardiovascular disease population

Generalized anxiety disorder (GAD) is a significant yet modifiable risk factor for worse cardiovascular disease (CVD) outcomes. The treatment of GAD in an accessible manner represents an unmet need in CVD, given that patients with CVD experience numerous barriers to in-person treatment engagement. This paper presents the rationale and design for an investigation of a strategy to enhance care for patients with CVD by introducing a scalable, affordable, and system-friendly digital intervention that targets a prominent modifiable risk factor (generalized anxiety and associated worry) for negative health behaviors in CVD. In the context of a randomized clinical trial design, we describe an experimental medicine approach for evaluating the degree to which a digital cognitive behavior therapy (dCBT), relative to a waitlist control group, engages anxiety and worry outcomes in a sample of 90 adults who have experienced an acute CVD event and who have comorbid GAD symptoms. We also investigate the degree to which dCBT leads to greater changes in GAD symptoms compared to the control condition and whether reductions in these symptoms are associated with corresponding reductions in cardiac anxiety and cardiac health behaviors (including smoking, physical activity, heart-healthy diet, and medication adherence). We propose that by targeting GAD symptoms in CVD in a way that does not tax ongoing medical care provision, we have the potential to improve the uptake of effective care and address both GAD and associated health behaviors.

Lysophosphatidylcholines modulate immunoregulatory checkpoints in peripheral monocytes and are associated with mortality in people with acute liver failure

Acute liver failure (ALF) is a life-threatening disease characterised by high-grade inflammation and immunoparesis, which is associated with a high incidence of death from sepsis. Herein, we aimed to describe the metabolic dysregulation in ALF and determine whether systemic immune responses are modulated via the lysophosphatidylcholine (LPC)-autotaxin (ATX)-lysophosphatidylcholinic acid (LPA) pathway. Ninety-six individuals with ALF, 104 with cirrhosis, 31 with sepsis and 71 healthy controls (HCs) were recruited. Pathways of interest were identified by multivariate statistical analysis of proton nuclear magnetic resonance spectroscopy and untargeted ultraperformance liquid chromatography-mass spectrometry-based lipidomics. A targeted metabolomics panel was used for validation. Peripheral blood mononuclear cells were cultured with LPA 16:0, 18:0, 18:1, and their immune checkpoint surface expression was assessed by flow cytometry. Transcript-level expression of the LPA receptor (LPAR) in monocytes was investigated and the effect of LPAR antagonism was also examined invitro. LPC 16:0 was highly discriminant between ALF and HC. There was an increase in ATX and LPA in individuals with ALF compared to HCs and those with sepsis. LPCs 16:0, 18:0 and 18:1 were reduced in individuals with ALF and were associated with a poor prognosis. Treatment of monocytes with LPA 16:0 increased their PD-L1 expression and reduced CD155, CD163, MerTK levels, without affecting immune checkpoints on T and NK/CD56+T cells. LPAR1 and 3 antagonism in culture reversed the effect of LPA on monocyte expression of MerTK and CD163. MerTK and CD163, but not LPAR genes, were differentially expressed and upregulated in monocytes from individuals with ALF compared to controls. Reduced LPC levels are biomarkers of poor prognosis in individuals with ALF. The LPC-ATX-LPA axis appears to modulate innate immune response in ALF via LPAR1 and LPAR3. Further investigations are required to identify novel therapeutic agents targeting these receptors. We identified a metabolic signature of acute liver failure (ALF) and investigated the immunometabolic role of the lysophosphatidylcholine-autotaxin-lysophosphatidylcholinic acid pathway, with the aim of finding a mechanistic explanation for monocyte behaviour and identifying possible therapeutic targets (to modulate the systemic immune response in ALF). At present, no selective immune-based therapies exist. We were able to modulate the phenotype of monocytes invitro and aim to extend these findings to murine models of ALF as a next step. Future therapies may be based on metabolic modulation; thus, the role of specific lipids in this pathway require elucidation and the relative merits of autotaxin inhibition, lysophosphatidylcholinic acid receptor blockade or lipid-based therapies need to be determined. Our findings begin to bridge this knowledge gap and the methods used herein could be useful in identifying therapeutic targets as part of an experimental medicine approach.

Tobacco quitlines: Opportunities for innovation to increase reach and effectiveness

The largest tobacco treatment network in North America, Tobacco Quitlines are an effective population-based approach to increase tobacco cessation; however, overall reach has decreased significantly in the past decade. A new generation of innovations responsive to evolving shifts in communication preferences, supported by research, and focused on increasing the impact of services have the potential to reinvigorate this network. The goal of this narrative review was to identify opportunities for innovation in Quitline service delivery, synthesize evidence for these opportunities, and identify gaps in the research. Innovation was defined as significant shift in current practice by utilizing novel theoretical concepts, approaches, methodologies, or interventions. The Experimental Medicine Approach informed the identification of gaps in the research. The specific domains were selected by reviewing previous reviews, commentaries, calls for action, and a recent report on promising practices. Evidence was garnered primarily from systematic reviews. Opportunities included automated and interactive digital therapeutics, novel health communications for stigma-free media campaigns, methods to increase access to nicotine replacement therapies, novel treatment options and combinations, and methods to promote engagement with digital therapeutics. Research topics that cross multiple domains include the consideration of theoretical frameworks, the identification of therapeutic targets and mechanisms of action, and the development of adapted approaches to address specific challenges and cultural responsivity. Finally, an examination is needed to understand how to improve the speed with which innovations are developed and implemented in this network.

Trazodone and patient outcomes in dementia-Limitations of naturalistic cohort data.

The unfolded protein response has been increasingly implicated as an important pathological pathway and target for therapeutic intervention in neurodegeneration. The licensed antidepressant trazodone is one drug which has been proposed to act on this pathway and may therefore be a potential therapy. Previous examination of existing data for patients with dementia prescribed trazodone did not find a signal suggesting a disease modifying effect. Here we add to that literature by examining the electronic patient record of patients with dementia in Cambridgeshire UK. We found that trazodone is rarely prescribed and where it is used it is at a dose less than half that predicted to be disease modifying. We also found that patients prescribed trazodone had higher levels of neuropsychiatric symptoms and were relatively late in the disease course, likely beyond the optimal point for therapeutic intervention. We suggest it is therefore premature to discard potential therapies based on observational data alone, particularly when experimental medicine approaches to examine the effects of trazodone are feasible.

"Mendelian randomisation and experimental medicine approaches to interleukin-6 as a drug target in pulmonary arterial hypertension." Mark Toshner, Colin Church, Lars Harbaum, et al. Eur Respir J 2022; 59: 2002463.

"Mendelian randomisation and experimental medicine approaches to interleukin-6 as a drug target in pulmonary arterial hypertension." Mark Toshner, Colin Church, Lars Harbaum, et al. Eur Respir J 2022; 59: 2002463.

Biological and clinical insights from a randomized phase 2 study of an anti-oncostatin M monoclonal antibody in systemic sclerosis.

The cytokine oncostatin M (OSM) is implicated in the pathology of SSc. Inhibiting OSM signalling using GSK2330811 (an anti-OSM monoclonal antibody) in patients with SSc has the potential to slow or stop the disease process. This multicentre, randomized, double-blind, placebo-controlled study enrolled participants ≥18 years of age with active dcSSc. Participants were randomized 3:1 (GSK2330811:placebo) in one of two sequential cohorts to receive GSK2330811 (cohort 1: 100 mg; cohort 2: 300 mg) or placebo s.c. every other week for 12 weeks. The primary endpoint was safety; blood and skin biopsy samples were collected to explore mechanistic effects on inflammation and fibrosis. Clinical efficacy was an exploratory endpoint. Thirty-five participants were randomized to placebo (n = 8), GSK2330811 100 mg (n = 3) or GSK2330811 300 mg (n = 24). Proof of mechanism, measured by coordinate effects on biomarkers of inflammation or fibrosis, was not demonstrated following GSK2330811 treatment. There were no meaningful differences between GSK2330811 and placebo for any efficacy endpoints. The safety and tolerability of GSK2330811 were not favourable in the 300 mg group, with on-target, dose-dependent adverse events related to decreases in haemoglobin and platelet count that were not observed in the 100 mg or placebo groups. Despite a robust and novel experimental medicine approach and evidence of target engagement, anticipated SSc-related biologic effects of GSK2330811 were not different from placebo and safety was unfavourable, suggesting OSM inhibition may not be a useful therapeutic strategy in SSc. ClinicalTrials.gov, NCT03041025; EudraCT, 2016-003417-95.

AgingPLUS: Theoretical Background and Study Design of the Randomized Trial

The AgingPLUS program targets three psychological mechanisms that are known barriers to middle-aged and older adults’ engagement in physical activity (PA): Negative views of Aging (NVOA), low self-efficacy beliefs, and poor goal planning skills. These risk factors are addressed in a 4-week intervention program that is compared to a generic health education program as the control group. Middle-aged and older adults (age 45-75 years) are enrolled in the trial for 8 months, with four assessment points: Baseline (pre-test), Week 4 (immediate post-test), Week 8 (delayed post-test), and Month 6 (long-term follow-up). The major outcome variables are participants’ engagement in PA as assessed via daily activity logs and actigraphs. Positive changes in NVOA, self-efficacy beliefs, and goal planning are the intervention targets and hypothesized mediating variables leading to increases in PA. This trial adopted the experimental medicine approach to assess the short- and long-term efficacy of the AgingPLUS program.

Behavior Change Interventions for Health Promotion in Physical Therapist Research and Practice: An Integrative Approach.

There is an increasing focus on health promotion in physical therapist research and practice. A clinical model (Health-Focused Physical Therapy Model) was developed for identifying major steps in the delivery of health promotion focusing on adoption of healthy lifestyle behaviors. One of the primary steps within this model is the design and delivery of behavior change interventions. Such interventions involve coordinated sets of activities that target change in a specific pattern of unhealthy behavior (eg, physical inactivity, smoking). This Perspective contends that the science and practice of behavior change interventions can be significantly advanced in the field of physical therapy (implementation science) through the integration of behavior change frameworks and techniques within the context of an experimental medicine approach for health behavior change. This perspective presents the integration of the Theoretical Domains Framework, the Behavior Change Wheel, including the Capability Opportunity Motivation-Behavior core system, and the Behavior Change Technique Taxonomy as a comprehensive approach for designing and delivering behavior change interventions in physical therapy. An experimental medicine approach is described, outlining a 4-step process in the design, delivery, and evaluation of behavior change interventions that can be applied to health promotion in physical therapist research and practice. The proposed integrative approach can advance public health and health promotion through healthy lifestyle behavior change in the field of physical therapy.

Translation of findings from laboratory studies of food and alcohol intake into behavior change interventions: The experimental medicine approach.

Objectives: Laboratory studies have contributed important information about the determinants of food and alcohol intake, and they have prompted the development of behavior change interventions that have been evaluated in randomized controlled trials conducted in the field. In this article we apply a recent experimental medicine (EM) framework to this body of research. Method: A conceptual review and focused discussion of the relevant literature is presented. Results: We illustrate how it is possible to translate findings from studies of food and alcohol intake in the laboratory into interventions that are effective for changing behavior in the real world. We go on to demonstrate how systematic failures can occur at different stages within the EM framework, and how these failures ultimately result in interventions that are ineffective for changing behavior. We also consider methodological issues that may constrain the external validity of findings from laboratory studies including demand effects, participant characteristics, and the timing and dose of behavioral interventions. Throughout, we make recommendations to improve the translation of findings from laboratory studies into behavior change interventions that are effective in the field. Conclusions: Consideration of the EM framework will help to ensure that promising candidate interventions for eating and drinking that are identified in laboratory studies can fulfill their translational promise. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Mechanisms of self-persuasion intervention for HPV vaccination: Testing memory and autonomous motivation.

Objective: Optimizing a self-persuasion intervention app for adolescent HPV vaccination requires investigating its hypothesized mechanisms. Guided by the experimental medicine approach, we tested whether (a) self-persuasion intervention components (verbalize vaccination reasons, choose HPV topics) changed putative mechanisms (memory, autonomous motivation) and (b) measures of the putative mechanisms were associated with HPV vaccination. Method: These are secondary analyses from a randomized 2 (cognitive processing: verbalize reasons vs. listen) × 2 (choice: choose HPV topics vs. assigned) factorial trial (Tiro et al., 2016). Undecided parents (N = 161) with an unvaccinated child (11-17 years old) used the self-persuasion app, recalled reasons for vaccination (memory measure), and completed an autonomous motivation measure. Adolescent vaccination status was extracted from electronic medical records 12 months postintervention. Results: The verbalize component resulted in greater recall accuracy of vaccination reasons (p < .001); however, the choose topics component did not increase autonomous motivation scores (p = .74). For associations with HPV vaccination, recall accuracy was not associated (ps > .51), but autonomous motivation scores significantly predicted vaccination (ps < .03), except when controlling for baseline motivation (p = .22). Conclusion: The intervention app engages parents in reasons for vaccination; however, memory may not be a viable mechanism of vaccination. Although the intervention did not affect autonomous motivation, associations with vaccination status suggest it is a viable intervention target for HPV vaccination but alternative strategies to change it are needed. Future testing of a refined app should examine implementation strategies to optimize delivery in clinical or community settings. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Modeling longitudinal variation in affective response to exercise across a 16-week randomized control trial (RCT).

Objective: Consistent with the Science of Behavior Change (SOBC) experimental medicine approach, this early phase intervention development study examines the influence of an intervention strategy (exercise training) on a behavioral health outcome (exercise engagement) in the service of addressing a widespread threat to public health (physical inactivity). Method: Physically inactive participants (N = 201) were randomly assigned to one of four exercise training conditions fully crossed on intensity (moderate, vigorous) and duration (short, long). Training occurred over 16-weeks and in-bout assessments of affective response (valence) and ratings of perceived exertion (RPE) were collected during Weeks 1, 4, 8, and 16. Cardiorespiratory fitness (VO₂max) was assessed pre- or postintervention and exercise behavior was assessed at 6-months postintervention follow-up. Results: Across conditions, affective response to exercise did not change, on average, over 16-weeks. Conversely, RPE decreased slightly, on average, over time. Participants completing vigorous intensity exercise reported more negatively valenced affective response and higher RPE, on average, across weeks. Greater total exercise volume completed and greater change in VO₂max were associated with more negatively valenced affective response, on average. Baseline affective response scores were positively associated with exercise minutes at follow-up; however, average affective response scores across the intervention were not associated with minutes of exercise at follow-up. Conclusions: Affective response to exercise did not become more positive in valence over time as a function of training volume or change in VO₂max. Implications for translating these findings to inform future intervention development efforts are discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Alcohol-involved sexual aggression: Emotion regulation as a mechanism of behavior change.

Sexual aggression remains a significant public health problem, with the majority of sexual assaults involving alcohol. Founded upon an experimental medicine approach to behavior change, the current study used a proximal change experiment to target and test emotion regulation (ER) as a mechanism underlying alcohol-involved sexual aggression. Heavy episodic drinking men aged 21-30 with a sexual assault perpetration history (N = 209) were randomly assigned to a brief, online, ER-focused cognitive restructuring or mindfulness intervention or to control. Intervention effects were evaluated during sober and intoxicated states through laboratory-based alcohol administration (target BrAC = .08%). Intoxicated and sober participants completed a proximal change protocol that included implementing ER skills during a sexual aggression analogue that assessed relevant emotions and intentions. Path analysis demonstrated that relative to control, the cognitive restructuring intervention improved emotional modulation and emotional clarity, resulting in lower sexual arousal and anger, respectively, followed by decreased sexual coercion intentions. The mindfulness intervention yielded mixed results, predicting decreased sexual aggression intentions compared to control but also predicting stronger coercive tactic intentions in intoxicated men with more severe sexual aggression histories. Both interventions improved emotional acceptance relative to control, but only for sober men. Overall, the current study demonstrated that ER-focused interventions improved proximal ER skills associated with reduced sexual aggression intentions, signifying ER as an important mechanism for changing sexually aggressive behavior. Because intervention efficacy varied by intoxication state, further research is needed to assess the effectiveness of ER interventions targeting real-world alcohol-involved sexual aggression. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Intermittent theta burst stimulation of cerebellar vermis enhances fronto-cerebellar resting state functional connectivity in schizophrenia with predominant negative symptoms: A randomized controlled trial

ObjectiveNegative symptoms of schizophrenia are substantially disabling and treatment resistant. Novel treatments like repetitive transcranial magnetic stimulation (TMS) need to be examined for the same using the experimental medicine approach that incorporates tests of mechanism of action in addition to clinical efficacy in trials. MethodsStudy was a double-blind, parallel, randomized, sham-controlled trial recruiting schizophrenia with at least a moderate severity of negative symptoms. Participants were randomized to real or sham intermittent theta burst stimulation (iTBS) under MRI-guided neuro-navigation, targeting the cerebellar vermis area VII-B, at a stimulus intensity of 100% active motor threshold, two sessions/day for five days (total = 6000 pulses). Assessments were conducted at baseline (T0), day-6 (T1) and week-6 (T2) after initiation of intervention. Main outcomes were, a) Scale for the Assessment of Negative Symptoms (SANS) score (T0, T1, T2), b) fronto-cerebellar resting state functional connectivity (RSFC) (T0, T1). ResultsThirty participants were recruited in each arm. Negative symptoms improved in both arms (p < 0.001) but was not significantly different between the two arms (p = 0.602). RSFC significantly increased between the cerebellar vermis and the right inferior frontal gyrus (pcluster-FWER = 0.033), right pallidum (pcluster-FWER = 0.042) and right frontal pole (pcluster-FWER = 0.047) in the real arm with no change in the sham arm. ConclusionCerebellar vermal iTBS engaged a target belonging to the class of cerebello-subcortical-cortical networks, implicated in negative symptoms of schizophrenia. However, this did not translate to a superior clinical efficacy. Future trials should employ enhanced midline cerebellar TMS stimulation parameters for longer durations that can potentiate and translate biological changes into clinical effects.