S. Potvin

Université de Montréal | UdeM · Department of Psychiatry

1) Background: Avatar Therapy (AT) is currently being studied to help patients suffering from treatment-resistant schizophrenia. Facilitating annotations of immersive verbatims in AT by using classification algorithms could be an interesting avenue to reduce the time and cost of conducting such analysis and adding objective quantitative data in the...

Considering the harmful effects of cannabis on individuals with a severe mental disorder and the limited effectiveness of current interventions, this case report showcases the beneficial results of a 10-session Avatar intervention for cannabis use disorder (CUD) on a polysubstance user with a comorbid schizoaffective disorder. Virtual reality allow...

Introduction Auditory verbal hallucinations (AVH), which often present in individuals with schizophrenia, can cause great psychological distress. Although antipsychotic medication can reduce AVH, 30% of patients will be resistant. Treatment resistance could be associated with important consequences, and there are only few treatment alternatives. Un...

Introduction Recent longitudinal studies point towards the existence of a positive relationship between cannabis use and violence in people with severe mental disorders. However, the existence of a dose-response relationship between the frequency and/or the severity of cannabis use and violence has seldom been investigated. Objectives This study a...

Introduction Cannabis use disorder (CUD) is a complex issue, even more so when it is comorbid with a psychotic disorder or a mood disorder. Indeed, this population seems more vulnerable to this substance since the incidence of developing CUD is five to six times higher. Psychotherapies have only shown a modest short-term effect that is not maintain...

Context: Emotion regulation is a set of processes responsible for controlling, evaluating and adjusting reactions to achieve a goal. Results derived from magnetic resonance imaging agreed on the involvement of frontal and limbic structures in this process. Findings using cognition and physiology interactions are still scarce but suggest a role of...

Background Emotional responses are an important component of psychotherapeutic processes. Avatar therapy (AT) is a virtual reality-based therapy currently being developed and studied for patients suffering from treatment resistant schizophrenia. Considering the importance of identifying emotions in therapeutical processes and their impact on the th...

This meta-review aimed to summarize the current state of knowledge provided by meta-analyzes on the efficacy of psychotherapies for substance use disorders. A systematic search was performed in PubMed, PsycINFO, Web of Science and Google Scholar. Meta-analyzes were included if they quantitatively examined the efficacy of a psychotherapy on substanc...

(1) Background: The therapeutic mechanisms underlying psychotherapeutic interventions for individuals with treatment-resistant schizophrenia are mostly unknown. One of these treatment techniques is avatar therapy (AT), in which the patient engages in immersive sessions while interacting with an avatar representing their primary persistent auditory...

Over the past years, research has shown that primary (high callousness and low anxiety) and secondary (high callousness and anxiety) variants of CU traits may be associated with opposite amygdala activity (hypo- and hyper-reactivity, respectively). However, their differences in amygdala functional connectivity remains largely unexplored. We conduct...

Cannabis use disorder (CUD) is a complex issue, even more so when it is comorbid with a severe mental disorder (SMD). Available interventions are at best slightly effective, and their effects are not maintained over time. Therefore, the integration of virtual reality (VR) may increase efficacy; however, it has not yet been investigated in the treat...

A persistent effort in neuroscience has been to pinpoint the neurobiological substrates that support mental processes. The Research Domain Criteria (RDoC) aims to develop a new framework based on fundamental neurobiological dimensions. However, results from several meta-analysis of task-based fMRI showed substantial spatial overlap between several...

Ketamine administration leads to a psychotomimetic state when taken in large bolus doses, making it a valid model of psychosis. Therefore, understanding ketamine’s effects on brain functioning is particularly relevant. This meta-analysis focused on neuroimaging studies that examined ketamine-induced brain activation at rest and during a task. Inclu...

Abstract: (1) Background: Very little is known about the inner therapeutic processes of psychotherapy interventions for patients suffering from treatment-resistant schizophrenia. Avatar therapy (AT) is one such modalities in which the patient is undergoing immersive sessions in which they interact with an Avatar representing their main persistent a...

Avatar Therapy has a significant impact on symptoms, beliefs, and quality of life of patients with treatment-resistant schizophrenia. However, little is known about how these changes are implemented into their lives and to which aspects of their lives these improvements relate. Ten consecutive patients enrolled in an ongoing clinical trial were ass...

Background Early evidence suggests that unexpected non-reward may increase the risk for aggressive behaviors. Despite the growing interest in understanding brain functions that may be implicated in aggressive behaviors, the neural processes underlying such frustrative events remain largely unknown. Furthermore, meta-analytic results have produced d...

Introduction: Recent longitudinal studies point toward the existence of a positive relationship between cannabis use and violence in people with severe mental disorders (SMD). However, the existence of a dose-response relationship between the frequency/severity of cannabis use and violence has seldom been investigated. Therefore, this study aims to...

A recent meta-analysis of resting-state functional connectivity studies revealed that individuals exhibiting anti- social behaviors or conduct problems may show disrupted brain connectivity in networks underpinning socio- affective and attentional processes. However, studies included in the meta-analysis generally rely on small sample sizes and sub...

The objective of this cross-sectional study was to identify cannabis-related features and other characteristics predictive of violence using a data-driven approach in patients with severe mental disorders (SMDs). A Least Absolute Shrinkage and Selection Operator regularization regression model was used on the database consisting of 97 patients with...

Background A growing number of studies highlight the importance of emotion regulation in the treatment and recovery of individuals with psychosis and concomitant disorders such as substance use disorder (SUD), for whom access to integrated dual-disorder treatments is particularly difficult. In this context, dedicated smartphone apps may be useful t...

SSRN is an open-access online preprint community providing valuable services to leading academic schools and government institutions. Specializing primarily in social sciences, including economics, law, corporate governance, and humanities, SSRN is branching out in to other science disciplines providing opportunities for scholars to post their earl...

Background: Ineffective cannabis regulatory frameworks such as prohibition have sparked interest in alternative solutions to reduce individual and societal harms. While it has been suggested that the recreational legalization process has yielded early successes, the relatively recent implementation of the novel policies has provided a modest time f...

Etats des lieux sur les biais cognitifs chez les jeunes personnes psychotiques : évaluation et prise en charge des biais cognitifs spécifiques à la psychose.

A network of early psychosis-specific intervention programs at the University of Montreal in Montreal, Quebec, Canada, conducted a longitudinal naturalistic five-year study at two Urban Early Intervention Services (EIS). In this study, 198 patients were recruited based on inclusion/exclusion criteria and agreed to participate. Our objectives were t...

Objectives Increasing evidence implicates cannabis consumption as a key risk factor in the development of psychosis, but the mechanisms underpinning this relationship remain understudied. This study proposes to determine whether sleep disruption acts as a mediator of the cannabis-to-psychosis relationship. Study design This longitudinal study asses...

Avatar Therapy (AT) is a modern therapeutic alternative for patients with schizophrenia suffering from persistent auditory verbal hallucinations. Its intrinsic therapeutical process is currently qualitatively analyzed via human coders that annotate session transcripts. This process is time and resource demanding. This creates a need to find potenti...

Extensive literature suggests that the brain reward system is crucial in understanding the neurobiology of substance use disorders. However, evidence of reliable deficits in functional connectivity across studies on substance use problems remains limited. Therefore, a voxel‐wise seed‐based meta‐analysis using brain regions of the reward system as s...

Background The offset of a painful and unpleasant sensation can elicit pleasure. This phenomenon, namely pleasant pain relief (PPR), is attracting growing interest in research. While the cold pressor test (CPT) has been frequently used to study the inhibition of pain by the administration of another painful stimulation (inhibitory conditioned pain...

This study aimed to investigate the association between past-reported violent/aggressive behaviors and brain functional connectivity in male patients suffering from schizophrenia using a task modeling the interaction between negative emotion processing and response inhibition. Forty-four male patients with schizophrenia and twenty-two healthy male...

In the past decades, a growing body of evidence has suggested that some individuals may exhibit antisocial behaviors following brain lesions. Recently, some authors have shown that lesions underpinning antisocial behaviors may disrupt a particular brain network during resting-state. However, it remains unknown whether these brain lesions may alter...

Introduction: When investigating the role of facilitatory and inhibitory pain mechanisms such as conditioned pain modulation (CPM) and temporal summation of pain (TSP), it is important to take both into consideration in a single experimental model to provide the most information on subgroups of patients. Therefore, the objective of this study was...

Self-disturbances constitute a hallmark of psychosis, but it remains unclear whether these alterations are present in at-risk populations, and therefore their role in the development of psychosis has yet to be confirmed. The present study addressed this question by measuring neural correlates of self-other processing in youth belonging to three dev...

BACKGROUND: Psychiatric diseases are increasingly conceptualized as brain network disorders. Hundreds of resting-state functional magnetic resonance imaging (rsfMRI) studies have revealed patterns of functional brain dysconnectivity in disorders such as major depression disorder (MDD), bipolar disorder (BD) and schizophrenia (SZ). Although these di...

Introduction White matter abnormalities have been identified in major depressive disorder (MDD). Although several diffusion tensor imaging studies found decreased fractional anisotropy (FA) in MDD, the effect of antidepressants (AD) treatment on white matter integrity has been insufficiently studied. Objectives We sought to examine the effect of A...

Background Recent evidence suggests that adolescents exhibiting conduct problems (CP) may have disrupted brain connectivity at rest. However, these studies are generally characterized by small sample sizes and differ in terms of neuroimaging methodologies and chosen psychometric scales to assess CP. In parallel, evidence from genetic and structural...

Background Auditory hallucinations in patients with psychotic disorders may be very distressing. Unfortunately, a large proportion of individuals are resistant to pharmacological interventions and the gold-standard cognitive-behavioral therapy for psychosis offers at best modest effects. To improve therapeutic outcomes, several therapies have been...

Background Given the increasing acceptability and legalization of cannabis in some jurisdictions, clinicians need to improve their understanding of the effect of cannabis use on mood disorders. Objective The purpose of this task force report is to examine the association between cannabis use and incidence, presentation, course and treatment of bip...

Background: The association between cannabis and cognitive functions has been thoroughly studied in psychotic disorders, but conflictual/paradoxical results have emerged. This critical meta-review examined the magnitude of effects of cannabis on neurocognitive functions in patients with psychotic disorders provided by meta-analyses and evaluated th...

Purpose This study aims to develop immersive scenarios (immersive videos) to foster generalization of learning while addressing social cognition, a factor associated to violence in schizophrenia. The authors sought to develop immersive videos that generate a sense of presence; are socially realistic; and can be misinterpreted and, if so, lead to an...

Objectives: To describe, in a naturalistic setting, the impact of the early use of LAI-AP on functional outcomes of early psychosis patients as compared to oral antipsychotics (OAP). Methods: Longitudinal prospective 3-year naturalistic study of all consecutive admissions (n = 416) to two Early intervention services (EIS) for psychosis comparing...

BACKGROUND Chronic pelvic pain is a frequent debilitating condition in women suffering from endometriosis. Pharmacological and surgical treatments are not always efficient in controlling pain and present important restriction. Digital Therapeutics (DTx) are emerging as major non-pharmacological alternatives, aiming to extend the analgesic therapeut...

Background Chronic pelvic pain is a common and disabling condition in women living with endometriosis. Pharmacological and surgical treatments are not always effective at controlling pain and present important restrictions. Digital therapeutics (DTx) are emerging as major nonpharmacological alternatives that aim to extend the analgesic therapeutic...

Introduction Over the years, many psychosocial interventions for individual having both a psychotic spectrum disorder and a substance use disorder diagnoses have been developed and studied. However, there is a high dropout rate among this clinical population. Objectives This meta-analysis aims to replicate a previous meta-analysis on the effects o...

Background Impairment in cognition is frequently associated with acute ketamine administration. However, some questions remain unanswered as to which deficits are most prominent and what variables modulate these effects. Methods A literature search yielded 56 experimental studies of acute ketamine administration that assessed cognition in 1041 hea...

Background: In accordance with continuum and cognitive behaviour models of psychosis, cognitive biases precede the onset and the maintenance of positive symptoms. The Davos Assessment of Cognitive Biases Scale (DACOBS), a self-report measure, was developed to explore the prevalence of specific cognitive biases. This study aims to validate the Fren...

The aim of this study was to investigate the neural bases of facial emotion processing before the onset of clinical psychotic symptoms in youth belonging to well-defined developmental trajectories of psychotic-like experiences (PLEs). A unique sample of 86 youths was recruited from a population-based sample of over 3800 adolescents who had been fol...

As many as 43% of methamphetamine users will have a psychotic episode in their lifetime. Of these, 30% will develop a primary psychotic disorder, such as schizophrenia. The current state of the literature does not currently allow us to determine who will develop a primary psychotic disorder following a methamphetamine-induced psychosis (MIPD). This...

In the last decades, neuroimaging studies have attempted to unveil the neurobiological markers underlying pediatric psychiatric disorders. Yet, the vast majority of neuroimaging studies still focus on a single nosological category, which limit our understanding of the shared/specific neural correlates between these disorders. Therefore, we aimed to...

While research focus remains mainly on psychotic symptoms, it is questionable whether we are placing enough emphasis on improving the quality of life (QoL) of schizophrenia patients. To date, the predictive power of QoL remained limited. Therefore, this study aimed to accurately predict the QoL within schizophrenia using supervised learning methods...

Cue reactivity is one of the most frequently used paradigms in functional magnetic resonance imaging (fMRI) studies of substance use disorders (SUDs). Although there have been promising results elucidating the neurocognitive mechanisms of SUDs and SUD treatments, the interpretability and reproducibility of these studies is limited by incomplete rep...

Background: Cannabis is among the most consumed psychoactive substances world-wide. Considering changing policy trends regarding the substance, it is crucial to understand more clearly its potential acute and residual adverse effects from a public health viewpoint. Cognitive function is one of the targeted areas with conflicting findings. This met...

Objective: Although schizophrenia patients are at a heightened risk of exhibiting violent behaviours compared to the general population, few functional neuroimaging studies have explored the aberrant neurocircuitry un- derpinning such behaviours. This study aimed to identify disrupted resting-state activity and functional con- nectivity in schizoph...

Importance Extensive literature suggests that the brain reward system is crucial in understanding the neurobiology of substance use disorders. However, across studies on substance use problems, evidence of reliable disruptions in functional connectivity is limited. Objective To uncover deficient functional connectivity with the brain reward system...

Abstract Background:A growing body of literature has detailed the use of qualitative analyses to measure the therapeutic processes and intrinsic effectiveness of psychotherapies, which yield small databases. Nonetheless, these approaches have several limitations and machine learning algorithms are needed. Objective:The objective of this study is...

Objectifs La schizophrénie, en particulier la schizophrénie résistante aux traitements (SRT), est considérée comme l’un des troubles psychiatriques les plus invalidants en termes d’effets indésirables sur la qualité de vie (QV) des patients. La QV subjective est devenue une cible particulièrement cruciale qui devrait être améliorée avec le traiteme...

Objectifs Cette revue trouve sa motivation dans l’observation que la prise de décision clinique en santé mentale est limitée par la nature des mesures typiquement obtenues lors de l’entretien clinique et la difficulté des cliniciens à produire des prédictions justes sur les états mentaux futurs des patients. L’objectif est de présenter un survol re...

Objectif Proposer quelques repères pour faciliter le processus de création d’applications pour téléphones intelligents (apps) en santé mentale. Méthode Présentation brève de l’intérêt potentiel des apps et proposition argumentée d’étapes clés pour la création des apps. L’article se base sur une revue narrative, un retour d’expérience et des discuss...

Previous work provided conversion equations for overall indices of positive and negative symptomatology between the Positive and Negative Syndrome Scale (PANSS) and the Scales for the Assessment of Positive/Negative Symptoms (SAPS/SANS). Our objective was to provide such conversion equations for subdomains of positive and negative symptomatology in...

Epidemiological surveys suggest that excessive drinking is associated with higher risk of Alzheimer's disease (AD). The present study utilized data from the National Alzheimer's Coordinating Center data set to examine cognition as well as gray/white matter and ventricular volumes among participants with AD and alcohol use disorder (AD/AUD, n=52), A...

Introduction Mounting evidence has begun establishing a link between cannabis use and adverse psychotic outcomes in patients affected by psychosis. However, we have yet to determine if this relationship is maintained when controlling for important confounding variables. As such, the following systematic review aims to investigate if the association...

In recent years, several jurisdictions have revised their regulation policy toward both medical and recreational use of cannabis. These changes have elicited concerns regarding how legalization impacts academic achievement and work performance. This review evaluates the acute and long-term (residual) association between cannabis use and cognitive f...

Objectives: Patients admitted to psychiatric emergency services (PES) are highly heterogenous. New tools based on a transdiagnosis approach could help attending psychiatrists in their evaluation process and treatment planning. The goals of this study were to: (1) identify profiles of symptoms based on self-reported, dimensional outcomes in psychia...

Early evidence suggests that unexpected non-reward may increase the risk for aggressive behaviors. Despite the growing interest in understanding brain functions that may be implicated in aggressive behaviors, the neural processes underlying such frustrative events remain largely unknown. Furthermore, meta-analytic results have produced discrepant r...

In light of the recent changes in the legal status of cannabis in Canada, the understanding of the potential impact of the use of cannabis by individuals suffering from depression is increasingly considered as being important. It is fundamental that we look into the existing literature to examine the influence of cannabis on psychiatric conditions,...

In the past decade, there has been a growing interest in examining resting-state functional connectivity deficits in subjects with conduct and antisocial personality disorder. Through meta-analyses and literature reviews, extensive work has been done to characterize their abnormalities in brain activation during a wide range of functional magnetic...

Background: Robust evidence shows that schizophrenia is associated with significant cognitive impairments, including deficits in visuospatial abilities. While other cognitive domains have sparked several functional neuroimaging studies in schizophrenia, only a few brain activation studies have examined the neural correlates of visuospatial abiliti...

Social functioning is a central to the treatment of people with psychosis, even more so with the recovery movement promoting an optimal life in one's environment. A good ability to function socially is, among other things, associated with fewer future complications and a better overall quality of life. However, prognostic markers currently in use (...

Prefrontal cortical dysfunctions underlying inhibitory control deficits in addiction are complex and likely dependent on population characteristics. Here, we conducted a meta-analysis to examine alterations in brain activations during response inhibition in addicted individuals. We characterized imaging findings based on substance use status, diagn...

Objectives This review is motivated by the observation that clinical decision-making in mental health is limited by the nature of the measures obtained in conventional clinical interviews and the difficulty for clinicians to make accurate predictions about their patients' future mental states. Our objective is to offer a representative overview of...

Objectives Schizophrenia, particularly treatment-resistant schizophrenia (TRS), is one of the most disabling psychiatric disorders in terms of adverse effects on the quality of life (QOL) of patients. Subjective QOL has become a particularly crucial target that should be improved with treatment, since improved QOL may lead to recovery in patients w...

Objective To propose some key steps to facilitate the process of creating mental health smartphone applications (apps). Methods Brief presentation of the potential interest of apps and proposition of key steps for the creation of apps. The paper is based on a narrative review, a testimonial experience and some expert works. Results Apps have ubiqui...

Introduction Schizophrenia is a chronic and severe mental disorder. While research focus remains mainly on negative outcomes, it is questionable whether we are placing enough emphasis on improving their sense of well-being and functioning. This could be accessed through the study of the quality of life (QoL). To date, QoL prediction models mainly f...

BACKGROUND In the last decades, neuroimaging studies have attempted to unveil the neurobiological markers underlying pediatric psychiatric disorders. However, children diagnosed with such disorders are likely to receive an additional diagnosis in the following years. Yet, the vast majority of neuroimaging studies focus on a single nosological categ...