Luc Mallet's research while affiliated with University of Geneva and other places

Publications (152)

Article
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Obsessive-compulsive disorder (OCD) is a highly disabling mental illness that can be divided into frequent primary and rarer organic secondary forms. Its association with secondary autoimmune triggers was introduced through the discovery of Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal infection (PANDAS) and Pediatric...
Article
Deep brain stimulation is an effective treatment for obsessive–compulsive disorder but is rarely used. Action is needed by psychologists, psychiatrists and insurers so that patients with otherwise intractable cases can receive this therapy to improve their mental health.
Article
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Checking behavior is a natural and adaptive strategy for resolving uncertainty in everyday situations. Here, we aimed at investigating the psychological drivers of checking and its regulation by uncertainty, in non-clinical participants and controlled experimental settings. We found that the sensitivity of participants’ explicit confidence judgment...
Article
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Introduction Deep brain stimulation (DBS) of bilateral anteromedial subthalamic nucleus (amSTN) has been found to be helpful in a subset of patients with severe, chronic and treatment-refractory obsessive–compulsive disorder (OCD). Biomarkers may aid in patient selection and optimisation of this invasive treatment. In this trial, we intend to evalu...
Article
Introduction The neurobiology of Gilles de la Tourette syndrome (GTS) is known to involve cortico-striatal loops possibly under genetic control. Less is known about possible environmental triggers of GTS. Specifically, immune-related events following possible environmental inducers have been evoked, but important controversies still exist. Objecti...
Article
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Lack of behavioral flexibility has been proposed as one underlying cause of compulsions, defined as repetitive behaviors performed through rigid rituals. However, experimental evidence has proven inconsistent across human and animal models of compulsive-like behavior. In the present study, applying a similarly-designed reversal learning task in two...
Article
Objective In addition to heredity, exposure to early-life adversity is an important predisposing risk factor of suicidal behaviour. Although the association between Childhood Trauma (CT) and suicide risk is well documented, interactions between CT and suicidal behaviour in Treatment-Resistant Depression (TRD) populations have received little covera...
Article
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Background Obsessive–compulsive disorder (OCD) is a major cause of disability in western country and responsible for severe impairment of quality of life. About 10% of patients present with severe OCD symptoms and require innovative treatment such as deep brain stimulation (DBS). Among possible targets, the non-motor subthalamic nucleus (STN) is a...
Article
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For over 10 years, electrical stimulation within the limbic cor-ticosubcortical network has been evaluated for treating patients with severe obsessive-compulsive disorder (OCD) (1). High-frequency deep brain stimulation (DBS) of various targets has been tested, including the anteromedial part of the subthalamic nucleus (amSTN), nucleus accumbens (N...
Article
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Background Cocaine addiction is a global health issue with limited therapeutic options and a high relapse rate. Attentional bias towards substance-related cues may be an important factor for relapse. However, it has never been compared in former and current cocaine-dependent patients. Methods Attentional bias towards cocaine-related words was asse...
Article
Background Subthalamic nucleus (STN) deep brain stimulation (DBS) alleviates obsessive-compulsive disorder (OCD) symptoms, suggesting that this basal ganglia structure may play a key role in integrating limbic and motor information. We explored the modulation of STN neural activity by visual emotional information under different motor demands. Met...
Chapter
Despite the range of conventional treatments available for obsessive–compulsive disorders, generally based on pharmacological and behavioural therapy, a significant number of patients receive no benefit from them. Clearly, further work is required to develop alternative therapeutic approaches to improve the treatment of the dysfunctional cognitive...
Article
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Objective Between 40 and 60% of patients with obsessive-compulsive disorder (OCD) are resistant to first-line treatments, including exposure and response prevention techniques. Those are likely to benefit from the rise of virtual reality (VR). However, very few studies have been conducted on the use of VR in OCD with several limitations including a...
Preprint
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Symptom comorbidity is present amongst neuropsychiatric disorders with repetitive behaviours, complicating clinical diagnosis and impeding appropriate treatments. This is of particular importance for obsessive-compulsive disorder (OCD) and Tourette syndrome. Here, we meticulously analysed the behaviour of Sapap3 knockout mice, the recent rodent mod...
Article
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Obsessive-Compulsive Disorder (OCD) is a neuropsychiatric disorder comprises repetitive intrusive thoughts and behaviours leading to significant handicap. 20% of patients are refractory to medication and cognitive behavioural therapy. Refractory OCD is associated with suicidal behaviour and significant degradation of social and professional functio...
Article
Vagus nerve stimulation (VNS) is an old, yet new, option for treatment-resistant depression. Despite several clinical trials over the last 15 years showing a consistent benefit-risk balance of the technic, VNS still struggles to find its place in our therapeutic algorithms. This is especially true in France, where only a few surgeries have been per...
Article
Earlier this year Acta Psychiatrica Scandinavica published a systematic review and meta‐analysis of oxidative and nitrosative stress markers in obsessive‐compulsive disorder (1). We were the authors of this manuscript that was, to the best of our knowledge, the first to summarize and analyse previously published data on this subject. The results of...
Article
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Objective: Trichotillomania (TTM) is characterized by the pulling out of one's hair. TTM was classified as an impulse control disorder in DSM-IV, but is now classified in the obsessive-compulsive related disorders section of DSM-5. Classification for TTM remains an open question, especially considering its impact on treatment of the disorder. In t...
Article
Objective Obsessive‐compulsive disorder (OCD) is a chronic, prevalent and highly impairing psychiatric illness. Although the pathophysiology of OCD remains unknown, pathways involved in oxidative and nitrosative stress (O&NS) have been implicated. The present study aims to systematically review the literature for quantitative evidence that patients...
Preprint
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Background: Compulsive behaviors, one of the core symptoms of Obsessive-Compulsive Disorder (OCD), are defined as repetitive behaviors performed through rigid rituals. The lack of behavioral flexibility has been as being one of the primary causes of compulsions, but studies exploring this dimension have shown inconsistencies in different tasks perf...
Article
La stimulation cérébrale profonde est une technique qui consiste à poser par voie neurochirurgicale des électrodes dans une zone cérébrale précise sous contrôle stéréotaxique. Ces électrodes sont reliées à un stimulateur posé au niveau thoracique et délivrent un courant. La stimulation par des courants de haute fréquence du noyau sous-thalamique es...
Article
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In the international context of efforts to combat the stigmatization of people with mental health problems, representations and attitudes about these illnesses have not to date been widely investigated in France. However, new technologies offer an unprecedented opportunity to collect such information on a large scale and to deploy more efficient ac...
Article
Le trouble lié à l’usage de cocaïne est à l’origine de nombreuses complications médicales, psychiatriques et sociales. De plus, ce trouble est associé à une multiplication par 4 du risque de mortalité standardisé. Les patients qui présentent une dépendance constituée à la cocaïne sont souvent difficiles à capter dans les soins. Enfin, il n’existe p...
Article
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Reversal learning (RL) has been widely used for assessment of behavioral adaptation, impulsivity, obsession, and compulsion in healthy controls as well as people suffering from psychiatric and neurological disorders such as Parkinson’s disease (PD). Nevertheless, studies addressing high cognitive functions such as metacognition in PD are scarce. He...
Article
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Obsessive–compulsive disorder (OCD) affects about 2% of the general population, for which several etiological factors were identified. Important among these is immunological dysfunction. This review aims to show how immunology can inform specific etiological factors, and how distinguishing between these etiologies is important from a personalized t...
Article
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Deep brain stimulation (DBS) has been offered to patients suffering of severe and resistant neuropsychiatric disorders like Obsessive Compulsive Disorder (OCD), Gilles de la Tourette Syndrome (TS) and Major Depression (MDD). Modulation of several targets within the cortico-striato-thalamo-cortical circuits can lead to a decrease of symptom severity...
Article
Background: Current neurocognitive models suppose dysfunctions of associative and limbic cortico-basal ganglia circuits to be at the core of obsessive-compulsive disorder (OCD). As little is known about the state of underlying anatomical connections, we investigated whether these connections were reduced and/or not properly organised in OCD patien...
Article
The obsessive compulsive disorder (OCD) is a psychiatric disorder with a high prevalence (2‑3 %), frequently causing a disabling condition. Drug and psychotherapeutic treatment is generally effective. However about 1/3 of the patients are treatment-resistant, suffering from chronic psychological distress with important sociofunctional repercussions...
Article
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Importance Collective evidence has strongly suggested that deep brain stimulation (DBS) is a promising therapy for Tourette syndrome. Objective To assess the efficacy and safety of DBS in a multinational cohort of patients with Tourette syndrome. Design, Setting, and Participants The prospective International Deep Brain Stimulation Database and R...
Article
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Background Major depression is characterized by (i) a high lifetime prevalence of 16–17% in the general population; (ii) a high frequency of treatment resistance in around 20–30% of cases; (iii) a recurrent or chronic course; (iv) a negative impact on the general functioning and quality of life; and (v) a high level of comorbidity with various psyc...
Article
Background Deep brain stimulation (DBS) has been proposed to treat patients with severe Tourette's syndrome, and open-label trials and two small double-blind trials have tested DBS of the posterior and the anterior internal globus pallidus (aGPi). We aimed to specifically assess the efficacy of aGPi DBS for severe Tourette's syndrome. Methods In t...
Article
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Background Subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment for the motor and non-motor signs of Parkinson’s disease (PD), however, psychological disorders and social maladjustment have been reported in about one third of patients after STN-DBS. We propose here a perioperative psychoeducation programme to limit such so...
Conference Paper
Introduction Les noyaux subthalamiques (NST) et pédonculopontin (NPP) appartiennent au réseau neuronal impliqué dans le contrôle de la locomotion et l’équilibre, particulièrement conservé d’un point de vue phylogénétique chez les vertébrés. Chez l’Homme, les données d’imagerie et les enregistrements électrophysiologiques suggèrent que seule l’activ...
Article
Résumé Le trouble obsessionnel compulsif (TOC) est une pathologie fréquente, potentiellement sévère, entraînant un handicap important pour le patient et représentant un fardeau pour son entourage. Malgré les traitements actuels, une part importante des patients est confrontée à des résistances, motivant la recherche de thérapeutiques nouvelles. Les...
Article
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INTRODUCTION Obsessive compulsive disorder (OCD) is one of the most disabling mental health disorders due to its negative impact on the patient's quality of life as well on that of her living caregivers. This disorder generates an additional burden for relatives, which may in turn affect the family dynamics and impair the evolution of the disease....
Article
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Obsessive-compulsive disorder (OCD) is a mental disorder featuring obsessions (intrusive thoughts) and compulsions (repetitive behaviors performed in the context of rigid rituals). There is strong evidence for a neurobiological basis of this disorder, involving limbic cortical regions and related basal ganglion areas. However, more research is need...
Presentation
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Voir : https://www.youtube.com/watch?v=6DW3rvRW6p0 et http://icm-institute.org/fr/actualite/lancement-de-crazyapp-une-web-application-sur-la-sante-mentale/
Presentation
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Conférence ”L’innovation en santé mentale”, donnée le 16/06/2016 dans le cadre du cycle de conférences ”Santé mentale : bousculons nos préjugés” de la Cité des Sciences de Paris par Xavier Briffault, Luc Mallet et Margot Morgiève.
Article
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Tourette Syndrome (TS) is a neuropsychiatric disease characterized by a combination of motor and vocal tics. Deep brain stimulation (DBS), already widely utilized for Parkinson’s disease and other movement disorders, is an emerging therapy for select and severe cases of TS that are resistant to medication and behavioral therapy. Over the last two d...
Article
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Aim: Cognitive behavioral therapy (CBT) is recognized as an effective treatment for obsessive-compulsive disorder (OCD). To maximize its effectiveness, we designed an "experimental" CBT defined by the addition of a computerized psychoeducative tool. Method: In a participative process involving patients through meetings of the French OCD associat...
Poster
Introduction Obsessive-Compulsive Disorder (OCD) is a mental disorder featuring obsessions (intrusive ideas) and compulsions which are repetitive behaviors performed through rigid rituals. This phenomenological observation has led to explore the idea that OCD patients have diminished behavioral flexibility. The pathophysiology of OCD support this h...
Article
La psychiatrie computationnelle est un champ émergent qui, dans le prolongement des évolutions récentes en neurosciences cognitives, cherche à comprendre les pathologies mentales par la modélisation des processus élémentaires de pensée et leurs dysfonctionnements. En explicitant l’implémentation neurobiologique des algorithmes utilisés par le cerve...
Article
Motion is a behavior involving a motor act programmed and executed in a particular cognitive and emotional context. Deep structures of the brain, including the basal ganglia, appear to play a crucial role in the integration of these three kinds of cortex information (motion, cognition, emotion). Through its organization, the basal ganglia system en...
Poster
Compulsive behavior is a core symptom of both obsessive compulsive disorder (OCD) and cocaine addiction (CA). Across both pathologies, one can identify a priori goal-directed actions (purportedly anxiolytic checking or washing in OCD and pleasure-seeking drug use in addiction) that turn into rigid, ritualized and repetitive behaviors over which the...
Article
Les troubles conduites suicidaires bénéficient d’une reconnaissance officielle dans le DSM-5. L’enjeu actuel vise à identifier les modalités de prise en charge de ces patients. Cette session abordera deux aspects thérapeutiques complémentaires, centrés sur les deux principaux facteurs de risque : tentative de suicide et dépression. G. Vaiva propose...
Article
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Background: Deep brain stimulation (DBS) has been proposed as an alternative to ablative neurosurgery for severe treatment-resistant Obsessive-Compulsive Disorder (OCD), although with partially discrepant results probably related to differences in anatomical targetting and stimulation conditions. We sought to determine the efficacy and tolerabilit...
Article
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It is thanks to great advances in the field of neuroscience, which allowed identifying dysfunctions in neural networks as the cause of many psychiatric and neurological diseases, that the number of indications for deep brain stimulation (DBS) has quickly expanded. Although the precise mechanism of action of DBS is unknown, this method probably work...
Conference Paper
Metacognition is the high-level psychological processes that enable to monitor and control one’s own cognitive functioning, e.g. the confidence one has in a perceptual decision. Despite “pathological doubt” being a core feature of obsessive-compulsive disorder and repetitive checking, a common OCD symptom, being conceivable as an ill-founded attemp...
Poster
Behavioral flexibility is the ability of a subject to change its behavior according to contextual cues. In humans, Obsessive Compulsive Disorders (OCD) is characterized by repetitive behavior, performed through rigid rituals. This phenomenological observation has led to explore the idea that OCD patients may have diminished behavioral flexibility....
Article
Le trouble obsessionnel compulsif (TOC) est une pathologie fréquente, touchant 2 à 3 % de la population [1]. L’implication de structures cortico-striato-thalamiques dans la symptomatologie du TOC est consensuellement reconnue [2]. Parmi elles, le cortex orbitofrontal (OFC), le cortex cingulaire antérieur (ACC) et le striatum ventral sont des struct...
Poster
Décider, c’est sélectionner une alternative parmi l’ensemble des options possibles pour atteindre nos buts. Les décisions perceptuelles correspondent à la sélection d’action sur la base de perceptions. Elles résultent de l’accumulation d’information sensorielle en faveur de chaque alternative jusqu’à un seuil de décision [1]. Nous avons précédemmen...
Article
Increasing evidence implicates abnormalities in corticostriatal circuits in the pathophysiology of obsessive-compulsive disorder (OCD) and OC-spectrum disorders. Parallels between the emergence of repetitive, compulsive behaviors and the acquisition of automated behaviors suggest that the expression of compulsions could in part involve loss of cont...
Article
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To further determine the causes of variable outcome from deep brain stimulation of the subthalamic nucleus (DBS-STN) in patients with Parkinson disease (PD). Data were obtained from our cohort of 309 patients with PD who underwent DBS-STN between 1996 and 2009. We examined the relationship between the 1-year motor, cognitive, and psychiatric outcom...