Portrait of Guillaume Dumas

Guillaume Dumas

Associate Academic Member
guillaume.dumas@mila.quebec
Associate Professor, Université de Montréal, Department of Psychiatry and Addiction
Adjunct Professor, McGill University, Department of Psychiatry
Research Topics
Computational Biology
Computational Neuroscience
Deep Learning
Dynamical Systems
Machine Learning Theory
Medical Machine Learning
Reinforcement Learning
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Biography

Guillaume Dumas is an associate professor of computational psychiatry in the Faculty of Medicine, Université de Montréal, and principal investigator in the Precision Psychiatry and Social Physiology laboratory at the Centre hospitalier universitaire (CHU) Sainte-Justine Research Centre. He holds the IVADO professorship for AI in Mental Health, and the Fonds de recherche du Québec - Santé (FRQS) J1 in AI and Digital Health. In 2023, Dumas was recognized as a CIFAR Azrieli Global Scholar – Brain, Mind, and Consciousness program, and nominated as a Future Leader in Canadian Brain Research by the Brain Canada Foundation.

Dumas was previously a permanent researcher in neuroscience and computational biology at the Institut Pasteur (Paris). Before that, he was a postdoctoral fellow at the Center for Complex Systems and Brain Sciences (Florida Atlanta University). He holds an engineering degree in advanced engineering and computer science (École Centrale Paris), two MSc degrees (theoretical physics, Paris-Saclay University; cognitive science, ENS/EHESS/Paris 5), and a PhD in cognitive neuroscience (Sorbonne University).

The goal of his research is to cross-fertilize AI/ML, cognitive neuroscience and digital medicine through an interdisciplinary program with two main axes:

- AI/ML for Mental Health, which aims to create new algorithms to investigate the development of human cognitive architecture and deliver personalized medicine in neuropsychiatry using data from genomes to smartphones.

- Social Neuroscience for AI/ML, which translates basic brain research and dynamical systems formalism into neurocomputational and machine learning hybrid models (NeuroML) and machines with social learning abilities (Social NeuroAI & HMI).

Current Students

Nadine Mohamed
Master's Research - Université de Montréal
nadine.mohamed@mila.quebec
Rémy Ramadour
Independent visiting researcher - CHU Sainte Justine / Université de Montréal
remy.ramadour.hsj@ssss.gouv.qc.ca
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Github
Mahta Ramezanian
Master's Research - Université de Montréal
Principal supervisor :
Irina Rish
mahta.ramezanian@mila.quebec
Pascal Tikeng Notsawo
PhD - Université de Montréal
Principal supervisor :
Guillaume Rabusseau
pascal.tikeng@mila.quebec
Website
Github
Google Scholar

Publications

Time to redefine psychosis: completing an integral conceptualization
Emmanuel Stip
Alexandre Hudon
Guillaume Dumas
Alexandre Dumais
To the Editor,We read with great interest the article An Integral Conceptualization of Psychosis (Benning, 2026). By integrating biological,… (see more) psychological, phenomenological, cultural, and social pe...
2026-09-09
Psychosis (published)
doi.org
Heterogeneity of brain dynamics in genetic and psychiatric conditions
Adrien E. E. Dubois
Sarah Lippé
Charles-Olivier Martin
Inga Sophia Knoth
Valerie Fontaine
Anne-Marie Bélanger
Pascale Abadie
Melissa T. Carter
Mélanie Couture
Mayada Elsabbagh
Alan Evans
Carl Ernst
Baudouin Forgeot d’Arc
Ridha Joober
Guy Rouleau
Julie Scorah
Christine Tardif
Ma'n H Zawati
Grace Westerkamp
Ernest V. Pedapati … (see 11 more)
Craig Erickson
Borja Rodríguez‐Herreros
Nadia Chabane
Kenza Latreche
Marie Schaer
Aline Lefebvre
Richard Delorme
Sara Jane Webb
James C. McPartland
Sébastien Jacquemont
Guillaume Dumas
Abstract Whether the heterogeneity of psychiatric conditions converges on shared neurophysiological alterations or translates into distinct … (see more)signatures remains unclear. We assembled high-density electroencephalogram (hd-EEG) resting-state recordings from 4,812 individuals aged 5 months to 66 years across 11 psychiatric conditions, a broad spectrum of rare genetic variants, and typically developing (TD) individuals. We established normative developmental trajectories of source-space EEG across spectral organization, connectivity, and signal complexity. Psychiatric conditions showed small deviations, revealing a shared transdiagnostic profile. In contrast, single rare variants showed substantially larger, distinct and sometimes mirror-opposite signatures that collapsed toward the psychiatric profile when pooled. Autism Spectrum Disorder showed some of the smallest group-level effects yet the largest individual deviations, indicating substantial but directionally inconsistent alterations. EEG deviations followed a cortical gradient, with larger effects in sensorimotor regions. We demonstrate that sample sizes in the hundreds are required for robust associations with psychiatric diagnoses. This interactive open resource provides normative scores to benchmark future results.
2026-09-07
bioRxiv (accepted)
doi.org
Temporal coupling as a design principle for social AI
Annemarie Wolff
Vincent Chamberland
Guillaume Dumas
Despite their ability to emulate social reasoning, current AI systems consistently fail at the dynamic, real-time coordination that defines … (see more)human social interaction. We argue this failure reflects a missing aspect in their design, not a limitation of scale or training data. Current AI systems model their partner from the outside and train on the data from interactions. Social intelligence, however, is not a property of an individual. It emerges when two coupled individuals interact and is developed through that coupling. We here argue that social AI should be built, and evaluated, as a coupled system with a human which targets an optimal, rather than maximal, alignment. This argument is based on two principles from research in social neuroscience. First, the training objective must change from predicting their interacting partner to a directed coupling that optimizes synchrony. Second, optimizing synchrony requires an embodied and organized temporal architecture which separates faster interactive generation with slower contextual comprehension. We show how coupling can be measured against benchmarks of human interaction and argue that this framing is a safety requirement. Together, these principles offer a neurobiologically grounded pathway toward AI systems capable of real-time social coordination with human partners.
2026-08-30
Zenodo (preprint)
doi.org
Outcomes of patients with Waldenström macroglobulinemia in ICU: a retrospective multicentric study
Camille Barraud
Aalliayah Velletrie
Stéphanie Harel
Frédéric Pène
Julien Charpentier
Antoine Guillon
Elie Azoulay
Michael Darmon
Emmanuel Canet
Anne-Sophie Moreau
Guillaume Dumas
Lucie Biard
Lara Zafrani
BACKGROUND Waldenström macroglobulinemia (WM) is a rare lymphoplasmacytic lymphoma, that can lead to life-threatening complications requiri… (see more)ng intensive care unit (ICU) admission. This study aimed to describe the clinical characteristics, WM-specific complications, and outcomes of WM patients admitted to the ICU. METHODS We conducted a multicenter retrospective study in 6 French ICUs including all patients with WM admitted between 2010 and 2024. The primary outcome was ICU mortality, analyzed using Ridge logistic regression. One-year mortality and associated risk factors were also assessed after ICU admission. RESULTS A total of 151 patients with WM were admitted to the ICU over the 14-year period. ICU mortality was 20% (n = 30), with infections being the leading cause of death. The main reason for admission was acute respiratory failure, and nearly half of the patients presented with sepsis at admission. The most WM-specific complications included hyperviscosity syndrome (n = 29, 19%) and other IgM-related vascular complications (n = 27, 18%). In Ridge logistic regression, a higher SOFA score (β = 0.099) and autoimmune haemolytic anemia (β = 0.058) were most strongly associated with ICU mortality, whereas, hyperviscosity syndrome (β = -0.045) showed the strongest negative association. The one-year mortality rate was 40% (n = 58) and remission at one year was achieved in 47% (n = 56) of treated patients. CONCLUSION This is the first large retrospective cohort of critically ill patients with WM. SOFA score and autoimmune cytopenias were most strongly associated with ICU mortality, highlighting the importance of both disease-specific complications and baseline severity, and supporting the need for tailored prognostic tools and individualized management strategies.
2026-08-28
Journal of Critical Care (published)
doi.org
Emotion reconfigures neuronal coordination across brains to control social choice
Francesco Papaleo
Federica Antonelli
Anna Monai
Fabrizio Bernardi
Atesh Koul
Nicola Marie Engel
Ilaria Carta
Francesca Managò
Arianna Benedetti
Anna Maria Borruto
LUDOVICO SPATTINI
Federica Maltese
Chunzhi Yi
Gian Marco Leggio
Guillaume Dumas
Stefano Panzeri
Giacomo Novembre
2026-08-27
Research Square (published)
doi.org
Green light exposure reduces central sensitization in cats with osteoarthritis-associated somatosensory impairment
Aliénor Delsart
Aude Castel
Guillaume Dumas
Frédéric Sauvé
Colombe Otis
Bertrand Lussier
Franck Péron
Marc Hébert
Nicolas Lapointe
Nicolas Quaegebeur
Pierre Grandjean
Maxim Moreau
Johanne Martel-Pelletier
Jean‐Pierre Pelletier
Eric Troncy
In humans, chronic pain is associated with multisensory hypersensitivity, which can be modulated by sensorial exposure. Although cats experi… (see more)ence chronic pain, their sensorial perception under this condition has never been investigated. Adult neutered healthy ( n = 6) or osteoarthritic ( n = 32) cats were assessed for functional alteration, central sensitization, and sensorial (olfactory and auditory) tolerance. The effects of specific light wavelengths were tested for neuromodulation via visual exposure. Hypersensitized cats displayed stronger unpleasant odor avoidance and lower sensitivity to repeated repulsive sounds. Odor avoidance correlated with delta and theta band proportions, inverse markers of endogenous inhibitory control. Functional alteration correlated with beta activity, a pain marker. After green light exposure, neuro-sensitization decreased for 80% of the less sensitized cats, and delta and theta band proportions increased further (no longer requiring inhibition), while beta and gamma band proportions decreased. Neuro-sensitization appears central in feline osteoarthritis pain, is associated with sensorial modifications, and is modulable by non-pharmacological approaches.
2026-08-26
iScience (published)
doi.org
Social interactions between people of same and different generations shape longitudinal changes in interpersonal neural synchrony, loneliness, and social connection
Ryssa Moffat
Guillaume Dumas
Emily S. Cross
Loneliness is globally acknowledged as a severe and burgeoning health risk, fueling interest in helping people of all ages form meaningful s… (see more)ocial connections. One promising approach consists of intergenerational social programs. While behavioral and qualitative evidence derived from such programs promise health and wellbeing benefits, the physiological consequences of repeated intergenerational encounters remain unknown. Insight into physiological changes will shed light on the mechanisms of social connection. We charted longitudinal changes in interpersonal neural synchrony (INS) in 31 intergenerational (older/younger adult) and 30 same-generation (younger adult) dyads across a six-session creative drawing program. At each session, dyads completed self-report measures, drew together and alone, and had their cortical activation recorded with fNIRS. In both groups, INS was greater while dyads drew together than alone. Across sessions, intergenerational dyads' INS decreased and same-generation dyads' INS increased. INS in RIFG~RTPJ and RIFG~RIFG were predictive of loneliness levels and feelings of social closeness, respectively. This exploratory longitudinal research reinforces the multi-faceted nature of INS dynamics as social connections are forged.
2026-08-19
PLOS Biology (published)
doi.org
Tuning in together: LSD enhances inter-brain synchrony and felt connectedness in romantic couples
Natasha L. Mason
Artur Czeszumski
Iva Totomanova
Filip Trbusek
Mauro Cavarra
Steph Ashton
Stefan Toennes
Eef Theunissen
Johannes Reckweg
P. L. Lockwood
Marieke DeWitte
Katrin Preller
Kim Kuypers
Guillaume Dumas
Pablo Mallaroni
Jan Ramaekers
Abstract Social connection is fundamental to human wellbeing. Serotonergic psychedelics such as lysergic acid diethylamide (LSD) acutely hei… (see more)ghten subjective connectedness, yet their effects on real-time social connection remain poorly understood. Using EEG hyperscanning in a randomized, double-blind, placebo-controlled crossover study, we recorded neural activity simultaneously from both members of healthy romantic couples (N=25) who received LSD (50 μg) or placebo together, across resting and interactive states. LSD increased subjective connectedness, including feelings of love, closeness, trust, and being “in sync,” while reducing loneliness, compared to placebo. This affiliative shift dissociated from the drug’s pharmacokinetic time-course, remaining elevated as subjective intensity and plasma concentration declined. In parallel, LSD increased inter-brain synchrony during shared rest, carried specifically by theta-band amplitude-envelope coupling. Importantly, this effect survived two complementary controls. First, it exceeded coupling between unrelated individuals and second the effects depended on contemporaneous neural alignment rather than shared drug-induced dynamics. Exploratory analyses showed that romantic partners with greater resting synchrony reported greater feelings of connectedness. These findings provide the first evidence that a psychedelic enhances brain-to-brain coupling between people, linking a pharmacologically induced state of felt connection to a measurable signature shared across interacting brains.
2026-08-17
bioRxiv (preprint)
doi.org
Determinants of functional burden pleiotropy and gene dosage responses across human traits
Sayeh Kazem
Kuldeep Kumar
Jane Yang
Florian Benitiere
Guillaume Huguet
Josephine Mollon
Thomas Renne
Laura M. Schultz
Emma E.M. Knowles
Worrawat Engchuan
Omar Shanta
Bhooma Thiruvahindrapuram
Jeffrey R. MacDonald
Celia M. T. Greenwood
Stephen W. Scherer
Laura Almasy
Jonathan Sebat
David C. Glahn
Guillaume Dumas
Sébastien Jacquemont
Pleiotropic and monotonic effects of gene dosage are central to understanding comorbidities in developmental pediatric and psychiatric disor… (see more)ders, yet the underlying biological processes are not well characterized. Here we develop a functional burden analysis to investigate the association of all protein-coding copy-number variants, genome-wide, with 43 complex traits in approximately 500,000 UK Biobank participants. We test variant associations disrupting 172 tissue or cell-type gene sets, finding associations for all traits, which we replicate in the All of Us cohort. Functional burden pleiotropy, defined as the number of traits significantly associated with a gene set, correlates with genetic constraint and is higher for brain than non-brain functions, even after normalizing for genetic constraint. Levels of pleiotropy, measured by burden correlation, are similar in deletions and loss-of-function single-nucleotide variants, and higher than in common variants and duplications. Most gene dosage responses are non-monotonic, with deletions and duplications showing same-direction effects, and monotonic responses decrease with genetic constraint. We observe associations between functional gene sets and traits for either deletions or duplications, but rarely both, with negatively correlated effect sizes. Together, these results link genetic constraint and brain-specific mechanisms to the whole-body multimorbidity of neurodevelopmental and psychiatric conditions. Gene dosage can help explain comorbidities in developmental pediatric and psychiatric disorders. Here, the authors map how rare copy-number variants disrupting tissue and cell-type gene sets shape 43 human traits.
2026-08-13
Nature Communications (published)
doi.org
Recent progress of large-scale biomarker consortia and paths forward in biomarker development for autism
Jason W. Griffin
Brianna Cairney
William E. Carson, IV
Lacey Chetcuti
Adrien E.E. Dubois
Guillaume Dumas
Sébastien Jacquemont
Shafali Jeste
Jacob P. Momsen
Adam J. Naples
James C. McPartland
2026-07-31
Biological Psychiatry (published)
doi.org
Enhancing Psychiatry Training Using an Agentic AI Simulated Consultation Tool: Prospective Cohort Study
Alice Rueda
Huda F Al-Shamali
Zack Cote
Niloy Roy
Reinhard Janssen‐Aguilar
Jithin Joseph
Bazen Gashaw Teferra
Mohammad Amin Kamaleddin
Lisa Burback
Olga Winkler
Bill Kapralos
Andrei Torres
Divya Sharma
Sridhar Krishnan
Guillaume Dumas
Andrew J. Greenshaw
Alexandre Hudon
Sanjeev Sockalingam
Yanbo Zhang
Adam Dubrowski … (see 1 more)
Venkat Bhat
Background: Canadian psychiatry residents must demonstrate consultation competency, assessed using the standardized assessment of a clinical… (see more) encounter report (STACER). However, opportunities to practice these skills and receive constructive assessment remain limited in clinical settings. Objective: This study aimed to evaluate the technical feasibility of an agentic AI system designed to support psychiatry residents' consultation competence through simulated patient encounters with a patient agent and structured feedback from a rater agent. Methods: We conducted a two-phase technical feasibility prospective single-arm cohort study of the STACER Agentic System, a large language model-based platform integrating a patient agent and a rater agent. Phase 1 involved automated evaluation of the patient agent using a psychiatrist agent across 227 synthetic major depressive disorder cases. Performance was assessed using DeepEval metrics (correctness, clarity, medical faithfulness, turn relevance, and role adherence) with descriptive statistics and 95% CIs. Phase 2 involved a preliminary user study with 14 convenience-sampled participants: a total of 5 members of the clinical research team and 9 psychiatry residents from the University of Alberta. Participants completed simulated diagnostic interviews and case presentations. Performance was evaluated using STACER-based scoring by the rater agent and 2 psychiatrists. Interrater reliability was assessed using intraclass correlation coefficients (α=.05). Participants rated realism, behavioral consistency, psychiatric nuance, and feedback utility using Likert scales and free-text answers. Results: The patient agent demonstrated high behavioral (51/56, 91.07%) and symptom fidelity (105/110, 95.45%), with strong automated performance (medical faithfulness mean 0.99, 95% CI 0.99-1.00; turn relevance 0.99, 95% CI 0.986-0.992). Participants rated simulations as psychiatrically plausible and diagnostically useful, particularly for depressive symptom representation, although rapport building was moderate (mean 2.78, SD 1.56 to mean 3.00, SD 1.41, out of 5.00) due to limited nonverbal cues. The rater agent generated structured STACER-aligned feedback with high intrarater consistency, especially at the section subtotal level. Interrater reliability with psychiatrists was poor at the item level (intraclass correlation coefficient range=0.25-0.49) but improved to good-to-excellent agreement at the section level for psychiatry resident sessions (intraclass correlation coefficient range=0.89-0.93). The rater agent's scores fell between those of the 2 psychiatrists for the clinical research team and were lower than both human raters for psychiatry residents. Conclusions: The STACER Agentic System demonstrates the technical feasibility of using agentic AI to simulate psychiatric consultations and deliver STACER-aligned formative feedback. By combining adaptive multiturn psychiatric simulation with competency-based evaluation, it shows promise in supporting cognitive aspects of consultation, though it remains limited in facilitating relational skills such as rapport building. These findings suggest agentic AI could expand scalable, low-risk opportunities for deliberate practice and formative feedback in competency-based psychiatric education. Further controlled studies are needed to evaluate educational effectiveness and integration into residency training.
2026-07-20
JMIR Medical Education (published)
doi.org
Tetradic Dynamics of Dyadic Sensorimotor Coordination: A Multiscale EEG Hyperscanning Study
Emmanuel Olarewaju
Lena Palaniyappan
Guillaume Dumas
How do leader and follower roles shape the brain mechanisms that support coordinated action between people? This question has direct therape… (see more)utic relevance for conditions such as schizophrenia and autism spectrum disorder, where the capacity for reciprocal social coordination is a defining vulnerability. Here, we propose a tetradic framework and examine sensorimotor coordination in 16 healthy adult pairs using simultaneous dual-brain EEG hyperscanning, a 2 x 2 within-subject design crossing Role (Leader/Follower) and Condition (Mirroring/Matching). Mirroring required resonance with a partner's movement; Matching required its controlled transformation. This contrast was designed to dissociate automatic from controlled coordination processes across roles. Behaviourally, Mirroring produced a reaction-time advantage that was selective to Followers, a finding replicated in a combined cohort, and consistent with role-dependent attention-inhibition gating. At the neural level, sustained (tonic) activity was dominated by Matching-related frontoparietal engagement regardless of role, while time-resolved (phasic) activity revealed a Mirroring-dominant reorganization that differentiated into role-specific patterns: anticipatory gating in Leaders and post-response inhibitory rebound in Followers. Information-theoretic decomposition of inter-brain coupling identified a Leader-specific predictive signal in medial prefrontal and cingulate cortices, a Follower-specific adaptive signal across sensorimotor and temporal regions, and a shared redundancy scaffold in orbitofrontal and insular cortices. These findings characterize tetradic coordination within dyads as a multiscale, role-asymmetric architecture in which top-down predictive control and bottom-up adaptive regulation are functionally dissociable. The tetradic framework provides an organizing scaffold for this dissociation, and the role-specific signatures it reveals offer candidate biomarkers for clinical populations in whom interpersonal coordination is disrupted.
2026-06-24
bioRxiv (preprint)
doi.org