The neural signature of reality-monitoring: A meta-analysis of functional neuroimaging studies.

Distinguishing imagination and thoughts from information we perceived from the environment, a process called reality-monitoring, is important in everyday situations. Although reality monitoring seems to overlap with the concept of self-monitoring, which allows one to distinguish self-generated actions or thoughts from those generated by others, the two concepts remain largely separate cognitive domains and their common brain substrates have received little attention. We investigated the brain regions involved in these two cognitive processes and explored the common brain regions they share. To do this, we conducted two separate coordinate-based meta-analyses of functional magnetic resonance imaging studies assessing the brain regions involved in reality- and self-monitoring. Few brain regions survived threshold-free cluster enhancement family-wise multiple comparison correction (p < .05), likely owing to the small number of studies identified. Using uncorrected statistical thresholds recommended by Signed Differential Mapping with Permutation of Subject Images, the meta-analysis of reality-monitoring studies (k = 9 studies including 172 healthy subjects) revealed clusters in the lobule VI of the cerebellum, the right anterior medial prefrontal cortex and anterior thalamic projections. The meta-analysis of self-monitoring studies (k = 12 studies including 192 healthy subjects) highlighted the involvement of a set of brain regions including the lobule VI of the left cerebellum and fronto-temporo-parietal regions. We showed with a conjunction analysis that the lobule VI of the cerebellum was consistently engaged in both reality- and self-monitoring. The current findings offer new insights into the common brain regions underlying reality-monitoring and self-monitoring, and suggest that the neural signature of the self that may occur during self-production should persist in memories.

[Transcranial electrical brain stimulation methods for treatment of negative symptoms in schizophrenia]. / Transkranielle elektrische Hirnstimulationsverfahren zur Behandlung der Negativsymptomatik bei Schizophrenie.

In recent years noninvasive brain stimulation (NIBS) applications have emerged as a third and novel treatment option alongside psychopharmacology and psychotherapy in the treatment of mental diseases. It is assumed that NIBS could represent a supplement or (in some indications) even replacement to established therapeutic strategies, e.g. in disorders with high resistance to current treatment regimens, such as negative symptoms or cognitive impairments in schizophrenia. Although positive symptoms in schizophrenia can be treated sufficiently with antipsychotic drugs, patients with negative symptoms frequently suffer from persistent lack of impetus, cognitive decline, social withdrawal and loss of global functioning in the activities of daily life; however, in these cases, current treatment strategies exert only moderate effects, and new treatment options are urgently needed. This review article provides a summary of the clinical effects of new electrical NIBS methods, e.g. transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), and transcranial random noise stimulation (tRNS) for the treatment of negative symptoms in schizophrenia. These new NIBS methods could help restore the disrupted neuronal networks and improve disturbed connectivity, especially of the left dorsolateral prefrontal cortex and left temporoparietal junction. Promising results are reported for the treatment of negative symptoms with tDCS, tACS and tRNS and could thus represent new therapeutic options in the treatment of schizophrenia.

Evidence-Based Guidelines and Secondary Meta-Analysis for the Use of Transcranial Direct Current Stimulation in Neurological and Psychiatric Disorders.

BACKGROUND: Transcranial direct current stimulation has shown promising clinical results, leading to increased demand for an evidence-based review on its clinical effects. OBJECTIVE: We convened a team of transcranial direct current stimulation experts to conduct a systematic review of clinical trials with more than 1 session of stimulation testing: pain, Parkinson's disease motor function and cognition, stroke motor function and language, epilepsy, major depressive disorder, obsessive compulsive disorder, Tourette syndrome, schizophrenia, and drug addiction. METHODS: Experts were asked to conduct this systematic review according to the search methodology from PRISMA guidelines. Recommendations on efficacy were categorized into Levels A (definitely effective), B (probably effective), C (possibly effective), or no recommendation. We assessed risk of bias for all included studies to confirm whether results were driven by potentially biased studies. RESULTS: Although most of the clinical trials have been designed as proof-of-concept trials, some of the indications analyzed in this review can be considered as definitely effective (Level A), such as depression, and probably effective (Level B), such as neuropathic pain, fibromyalgia, migraine, post-operative patient-controlled analgesia and pain, Parkinson's disease (motor and cognition), stroke (motor), epilepsy, schizophrenia, and alcohol addiction. Assessment of bias showed that most of the studies had low risk of biases, and sensitivity analysis for bias did not change these results. Effect sizes vary from 0.01 to 0.70 and were significant in about 8 conditions, with the largest effect size being in postoperative acute pain and smaller in stroke motor recovery (nonsignificant when combined with robotic therapy). CONCLUSION: All recommendations listed here are based on current published PubMed-indexed data. Despite high levels of evidence in some conditions, it must be underscored that effect sizes and duration of effects are often limited; thus, real clinical impact needs to be further determined with different study designs.

Impaired self-recognition in individuals with no full-blown psychotic symptoms represented across the continuum of psychosis: a meta-analysis.

BACKGROUND: Impairments in self-recognition (i.e. recognition of own thoughts and actions) have been repeatedly shown in individuals with schizophrenia. According to classical clinical characterizations, schizophrenia is included in a continuum encompassing a large range of genetic statuses, psychotic states and symptoms. The current meta-analysis aims to determine whether self-recognition is affected by individuals within the psychosis continuum. METHOD: Three populations were considered: people with an at-risk mental state for psychosis (ARMS), hallucination-prone individuals and unaffected relatives of patients with schizophrenia. Eleven studies contrasted self-recognition between these three populations (n = 386) and healthy controls (n = 315) and four studies used correlational analysis to estimate comparable effects (n = 629). Eligible studies used experimental paradigms including source-monitoring and self-monitoring. RESULTS: We observed significantly reduced self-recognition accuracy in these populations [g = -0.44 (-0.71 to -0.17), p = 0.002] compared to controls. No influence of the type of population, experimental paradigm or study design was observed. CONCLUSION: The present analysis argues for self-recognition deficits in populations with no full-blown psychotic symptoms represented across the continuum of psychosis.

Advancing clinical response characterization to frontotemporal transcranial direct current stimulation with electric field distribution in patients with schizophrenia and auditory hallucinations: a pilot study.

Transcranial direct current stimulation (tDCS) has been proposed as a therapeutic option for treatment-resistant auditory verbal hallucinations (AVH) in schizophrenia. In such cases, repeated sessions of tDCS are delivered with the anode over the left prefrontal cortex and the cathode over the left temporoparietal junction. Despite promising findings, the clinical response to tDCS is highly heterogeneous among patients. Here, we explored baseline differences between responders and nonresponders to frontotemporal tDCS using electric field modeling. We hypothesized that responders would display different tDCS-induced electric field strength in the brain areas involved in AVH compared to nonresponders.Using baseline structural MRI scans of 17 patients with schizophrenia and daily AVH who received 10 sessions of active frontotemporal tDCS, we constructed individual realistic whole brain models estimating electric field strength. Electric field maps were compared between responders (n = 6) and nonresponders to tDCS (n = 11) using an independent two-sample t test. Clinical response was defined as at least a 50% decrease of AVH 1 month after the last tDCS session.Results from the electric field map comparison showed that responders to tDCS displayed higher electric field strength in the left transverse temporal gyrus at baseline compared to nonresponders (T = 2.37; p = 0.016; 32 voxels).These preliminary findings suggested that the strength of the tDCS-induced electric field reaching the left transverse temporal gyrus could play an important role in the response to frontotemporal tDCS. In addition, this work suggests the interest of using electric field modeling to individualize tDCS and increase response rate.

Abnormalities of the late positive potential during emotional processing in individuals with psychopathic traits: a meta-analysis.

BACKGROUND: Individuals with psychopathic traits display deficits in emotional processing. A key event-related potential component involved in emotional processing is the late positive potential (LPP). In healthy controls, LPP amplitude is greater in response to negative stimuli than to positive or neutral stimuli. In the current study, we aimed to compare LPP amplitudes between individuals with psychopathic traits and control subjects when presented with negative, positive or neutral stimuli. We hypothesized that LPP amplitude evoked by emotional stimuli would be reduced in individuals with psychopathic traits compared to healthy controls. METHODS: After a systematic review of the literature, we conducted a meta-analysis to compare LPP amplitude elicited by emotional stimuli in individuals with psychopathic traits and healthy controls. RESULTS: Individuals with psychopathic traits showed significantly reduced LPP amplitude evoked by negative stimuli (mean effect size = -0.47; 95% CI -0.60 to -0.33; p < 0.005) compared to healthy controls. No significant differences between groups were observed for the processing of positive (mean effect size = -0.15; 95% CI -0.42 to 0.12; p = 0.28) and neutral stimuli (mean effect size = -0.12; 95% CI 0.31 to 0.07; p = 0.21). CONCLUSIONS: Measured by LPP amplitude, individuals with psychopathic traits displayed abnormalities in the processing of emotional stimuli with negative valence whereas processing of stimuli with positive and neutral valence was unchanged as compared with healthy controls.

Perceived ethnic discrimination as a risk factor for psychotic symptoms: a systematic review and meta-analysis.

BACKGROUND: Previous studies have shown an elevated risk of psychotic symptoms (PS) and experiences (PEs) among ethnic minority groups, with significant variation between groups. This pattern may be partially attributable to the unfavorable socio-environmental conditions that surround ethnic minority groups. Perceived ethnic discrimination (PED) in particular has been a salient putative risk factor to explain the increased risk. METHODS: We conducted a systematic literature review and meta-analysis to assess the impact of PED on reporting PS/PEs in ethnic minorities. This review abides by the guidelines set forth by Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The included studies were obtained from the databases: Medline, PsycINFO, and Web Of Science. Sub-group analyses were performed assessing the effect of PED in different subtypes of PS, the influence of ethnicity and moderating/mediating factors. RESULTS: Seventeen studies met the inclusion criteria, and nine were used to conduct the meta-analysis. We found a positive association between PED and the occurrence of PS/PEs among ethnic minorities. The combined odds ratio were 1.77 (95% CI 1.26-2.49) for PS and 1.94 (95% CI 1.42-2.67) for PEs. We found that the association was similar across ethnic groups and did not depend on the ethnic origin of individuals. Weak evidence supported the buffering effects of ethnic identity, collective self-esteem and social support; and no evidence supported the moderating effect of ethnic density. Sensitivity to race-based rejection significantly but only slightly mediated the association. CONCLUSION: These findings suggest that PED is involved in the increased risk of PS/PEs in ethnic minority populations.

Suicidal behaviors and ideation during emerging viral disease outbreaks before the COVID-19 pandemic: A systematic rapid review.

The current COVID-19 pandemic is the most severe pandemic of the 21st century, on track to having a rising death toll. Beyond causing respiratory distress, COVID-19 may also cause mortality by way of suicide. The pathways by which emerging viral disease outbreaks (EVDOs) and suicide are related are complex and not entirely understood. We aimed to systematically review the evidence on the association between EVDOs and suicidal behaviors and/or ideation. An electronic search was conducted using five databases: Medline, Embase, Web of Science, PsycINFO and Scopus in April 2020. A rapid systematic review was carried out, which involved separately and independently extracting quantitative data of selected articles. The electronic search yielded 2480 articles, of which 9 met the inclusion criteria. Most of the data were collected in Hong Kong (n = 3) and the USA (n = 3). Four studies reported a slight but significant increase in deaths by suicide during EVDOs. The increase in deaths by suicide was mainly reported during the peak epidemic and in older adults. Psychosocial factors such as the fear of being infected by the virus or social isolation related to quarantine measures were the most prominent factors associated with deaths by suicide during EVDOs. Overall, we found scarce and weak evidence for an increased risk of deaths by suicide during EVDOs. Our results inform the need to orient public health policies toward suicide prevention strategies targeting the psychosocial effects of EVDOs. High-quality research on suicide risk and prevention are warranted during the current pandemic.

A Case Report of Transcranial Magnetic Stimulation-Related Seizure in a Young Patient With Major Depressive Disorder Receiving Accelerated Transcranial Magnetic Stimulation.

We report here the case of a transcranial magnetic stimulation (TMS)-related seizure observed after an accelerated TMS protocol in a young patient with major depressive disorder. The protocol consisted of delivering 5 sessions per day during 4 consecutive working days over the left dorsolateral prefrontal cortex. Stimulations were delivered at 20 Hz, with 40 trains, train duration of 1.9 seconds, intertrain interval of 12 seconds, and 1560 pulses per session. The event occurred during the third session (out of 5) of the second day (out of 4) into the 26th train (out of 40). Twelve days after the event, new sessions of stimulation (30 sessions of 1 Hz, 6 trains, train duration of 60 seconds, intertrain 30 seconds, 360 stimulations per session) followed by a maintenance protocol (1 session every 2 weeks) were proposed to the patient. This strategy allows us to achieve and maintain remission.

[Transcranial direct current stimulation (tDCS) for obsessive-compulsive disorder: A new treatment option?] / Transkranielle Gleichstromstimulation (tDCS) bei Zwangsstörung: Eine neue Therapieoption?

More than 40 % of patients with obsessive-compulsive disorder (OCD) do not respond to established treatments despite advances in psychopharmacology and psychotherapy. Since a couple of years, non-invasive brain stimulation techniques gain importance in the treatment of psychiatric disorders. Transcranial direct current stimulation (tDCS) uses weak constant direct current to modulate neuronal activation and changes the function of neuronal networks. This technique is recently investigated for the improvement of treatment resistant OCD symptoms. In this review we give a concise overview over the current state of the art and delineate further directions of tDCS application in OCD. The search in the NIH database pubmed and further manual search revealed nine case reports, three open label studies and one controlled study with two active arms. There is no sham controlled study yet. A total of 78 patients received active tDCS with a large variety of different electrode placements, with main target over dorsolateral prefrontal cortex, orbitofrontal cortex, and (pre-)supplementary motor areas. Although stimulation parameters were highly heterogeneous, reported cases show not only an improvement of OCD symptoms, but also an improvement of depression and anxiety symptoms in patients with treatment resistant OCD. This evidence is limited by the lack of sham-controlled studies and needs confirmation in larger studies.

Ethnic minority position and migrant status as risk factors for psychotic symptoms in the general population: a meta-analysis.

Psychotic symptoms (PS) are experienced by a substantial proportion of the general population. When not reaching a threshold of clinical relevance, these symptoms are defined as psychotic experiences (PEs) and may exist on a continuum with psychotic disorders. Unfavorable socio-environmental conditions, such as ethnic minority position (EMP) and migrant status (MS), may increase the risk of developing PS and PEs. We conducted an electronic systematic review and a meta-analysis assessing the role of EMP and MS for the development and persistence of PS in the general population. Sub-group analyses were performed investigating the influence of ethnic groups, host countries, age, types of PS, and scales. Twenty-four studies met our inclusion criteria. EMP was a relevant risk factor for reporting PS [odds ratio (OR) 1.44, 95% confidence interval (CI) 1.22-1.70) and PEs (OR 1.36, 95% CI 1.16-1.60). The greatest risk was observed in people from the Maghreb and the Middle East ethnic groups in Europe (OR 3.30, 95% CI 2.09-5.21), in Hispanic in the USA (OR 1.98, 95% CI 1.43-2.73), and in the Black populations (OR 1.85, 95% CI 1.39-2.47). We found a significant association between MS and delusional symptoms (OR 1.47, 95% CI 1.33-1.62). We found no association between EMP and persistence of PEs.EMP was associated with increased risk of reporting PS and PEs, and the risk was higher in ethnic groups facing deprivation and discrimination. We found an association between MS and delusional symptoms. These results raise questions about the precise role of socio-environmental factors along the psychosis continuum.

Frontal Transcranial Direct Current Stimulation Induces Dopamine Release in the Ventral Striatum in Human.

A single transcranial direct current stimulation (tDCS) session applied over the dorsolateral prefrontal cortex (DLFPC) can be associated with procognitive effects. Furthermore, repeated DLPFC tDCS sessions are under investigation as a new therapeutic tool for a range of neuropsychiatric conditions. A possible mechanism explaining such beneficial effects is a modulation of meso-cortico-limbic dopamine transmission. We explored the spatial and temporal neurobiological effects of bifrontal tDCS on subcortical dopamine transmission during and immediately after the stimulation. In a double blind sham-controlled study, 32 healthy subjects randomly received a single session of either active (20 min, 2 mA; n = 14) or sham (n = 18) tDCS during a dynamic positron emission tomography scan using [11C]raclopride binding. During the stimulation period, no significant effect of tDCS was observed. After the stimulation period, compared with sham tDCS, active tDCS induced a significant decrease in [11C]raclopride binding potential ratio in the striatum, suggesting an increase in extracellular dopamine in a part of the striatum involved in the reward-motivation network. The present study provides the first evidence that bifrontal tDCS induces neurotransmitter release in polysynaptic connected subcortical areas. Therefore, levels of dopamine activity and reactivity should be a new element to consider for a general hypothesis of brain modulation by bifrontal tDCS.

How Much Do Benzodiazepines Matter for Electroconvulsive Therapy in Patients With Major Depression?

BACKGROUND: Electroconvulsive therapy (ECT) is one of the most effective treatments for major depressive disorder (MDD), especially in cases of treatment-resistant MDD. Because of their pharmacological profiles, benzodiazepines (BZDs) are suspected to decrease the efficacy of ECT. This study investigated the effect of BZDs on ECT-induced clinical outcomes and ECT course parameters in patients with MDD. METHOD: The impact of BZDs on severity of depression (Montgomery-Asberg Depression Rating Scale scores) and on ECT course parameters (seizure threshold, clinical and electroencephalographic seizure duration) was investigated in 70 patients with MDD who received an ECT course using dose-titration method (22 received concomitant BZDs). RESULTS: Lower remission rates (52.0%) and smaller decreases in Montgomery-Asberg Depression Rating Scale scores were observed in the non-BZD group than in the BZD group (81.2%, P = 0.02). There were no significant differences between the 2 groups regarding seizure duration and seizure threshold. LIMITATIONS: This was a retrospective study. Impact of BZDs on anxiety and cognition was not assessed. CONCLUSIONS: Benzodiazepines increased the clinical efficacy of ECT when delivered using dose-titration method and bitemporal stimulation. Further studied are needed to understand the interaction between BZDs and ECT on clinical outcomes.

A Review of the Effects of Transcranial Direct Current Stimulation for the Treatment of Hallucinations in Patients With Schizophrenia.

Some 25% to 30% of patients with schizophrenia report auditory verbal hallucinations (AVHs) that fail to respond adequately to antipsychotic treatments. In such cases, transcranial direct current stimulation (tDCS) has been proposed as a therapeutic option. Here, we aim to provide an exhaustive review of the literature examining the clinical effects of tDCS on AVH in patients with schizophrenia. A systematic search in the PubMed and Web of Science databases yielded 14 results, 7 randomized controlled trials (RCTs) and 7 open-label studies. Among them, 4 RCTs and 7 open-label studies reported a significant reduction of AVH after repeated sessions of tDCS, whereas 3 RCTs did not show any advantage of active tDCS over sham tDCS. Altogether, current studies showed an overall decrease of approximately 26% of AVH after active tDCS and 11% after sham tDCS. One suitable approach to decreasing AVH was to deliver twice-daily sessions of tDCS over 5 consecutive days (10 sessions at 20 minutes each, 2 mA) with the anode over the left dorsolateral prefrontal cortex and the cathode over the left temporoparietal junction. Demographic and clinical parameters such as young age, nonsmoking status, and higher frequencies of AVH occurrence seemed to be predictors of clinical improvement. Further RCTs, with larger sample sizes, are needed to confirm the usefulness of tDCS for AVH.

Effects of theta-rhythm transcranial alternating current stimulation (4.5 Hz-tACS) in patients with clozapine-resistant negative symptoms of schizophrenia: a case series.

Our aim was to assess the efficacy and safety of theta-rhythm transcranial Alternating Current Stimulation (4.5 Hz-tACS) in patients with clozapine-resistant symptoms of schizophrenia. In an open case series, 3 patients received 20 sessions of 4.5 Hz-tACS (20 min, 2 mA) applied over the dorsolateral prefrontal cortex. The patients exhibited a decrease of negative symptoms (-10 %), general symptoms (-18 %) and an improvement of insight into the illness (-25 %). 4.5 Hz-tACS might be a suitable alternative treatment for clozapine-resistant symptoms of schizophrenia.

Persistent auditory hallucinations in out-patients with schizophrenia.

Objectives to estimate the prevalence of persistent auditory hallucinations (AHs) in a group of schizophrenic patients, to evaluate their dimensions and to identify their clinical associated factors. Method This was a cross-sectional study carried-on 144 out-patients followed for schizophrenia, according DSM-IV-TR criteria. The assessment was consisted by the collect of epidemiological, clinical and therapeutic data and the use of the Hoffman's auditory hallucinations rating scale (AHRS), and the positive and negative symptoms scale (PANSS). Results The prevalence of persistent AHs (AHRS score ≥ 5) was 40.3%. The mean total score of the AHRS was 10.7±7.8 for all patients and 19.4±7.7 for patients with persistent AHs. The AHs dimensions with higher sub-scores were the number, the influence and the reality of the voices. The PANSS items most related to the AHRS total score were P3 "hallucinatory activity", G1 "somatic concerns", G4 "tension" and the G5 "mannerisms and posture disorders". The clinical associated factors with persistent AHs after multivariate analysis were the absence of tobacco consumption, the hallucinatory onset of disorders, the notion of previous hospitalization and the continuous course. Conclusion Our results support the multidimensionality of AHs and confirm the existence of inter individual differences in the characteristics of these hallucinations. Persistent AHs were associated with poor prognosis, requiring more effective therapeutic strategies.

[Does Prefrontal Noninvasive Brain Stimulation Alleviating Symptoms in Depression and Schizophrenia Impact Mood and Emotion Processing?]. / Neurostimulation du cortex préfrontal dorsolatéral : quels effets sur la symptomatologie, l'humeur et les émotions dans la dépression et la schizophrénie ?

Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are noninvasive brain stimulation techniques currently used as therapeutic tools in various psychiatric conditions. Applied over the dorsolateral prefrontal cortex (DLPFC), they showed their efficacy in reducing drug-resistant symptoms in patients with major depression and in patients with schizophrenia with predominantly negative symptoms. The DLPFC is a brain structure involved in the expression of these symptoms as well as in other dysfunctional functions observed in theses conditions such as emotional processes. The goal of this review is to establish whether or not a link exists between clinical improvements and modulation of emotional processes following the stimulation of the DLPFC in both conditions. The data collected show that improved emotional processes is not linked to a clinical improvement neither in patients with depression nor in patients with negative schizophrenia. Our results suggests that although sharing common brain structures, the brain networks involved in both symptoms and in emotional processes would be separate.

Validation of the French Version of the Auditory Hallucination Rating Scale in a Sample of Hallucinating Patients with Schizophrenia.

OBJECTIVE: The aim of this study was to validate the French version of the 7-item Auditory Hallucination Rating Scale (AHRS) so as to facilitate fine-grained assessment of auditory hallucinations (AH) in native French-speaking patients with schizophrenia (SZ) in clinical settings and studies. METHOD: Patients (N = 66) were diagnosed with SZ according to the Diagnostic and Statistical Manual of Mental Disorders. The French version of the AHRS was developed using a forward­backward translation procedure. Psychometric properties of the French version of the AHRS were tested including (i) construct validity with a confirmatory one-factor analysis, (ii) internal validity with Pearson correlations and Cronbach α coefficients, and (iii) external validity by correlations with the Scale for Assessment of Positive Symptoms (SAPS-H1), the Positive and Negative Syndrome Scale (PANSS-P3; concurrent), the PANSS-Negative subscale and age of subjects (divergent), and inter-rater intraclass correlation coefficients (ICCs). RESULTS: (i) The confirmatory one-factor analysis found a root mean square error of approximation (RMSEA) = 0.00, 90% confidence interval = [0.000 to 0.011], and a comparative fit index = 0.994. (ii) Correlations between AHRS total score and individual items were mostly ≥0.4. Cronbach α coefficient was 0.61. (iii) Correlations with PANSS-P3 and SAPS-H1 were 0.42 and 0.53, respectively. In a subset of participants (N = 16), ICC values were extremely high and significant for AHRS total and individual item scores (ICCs range 0.899 to 0.996). CONCLUSION: The French version of the AHRS is a psychometrically acceptable instrument for the evaluation of AH severity in French-speaking patients with SZ.

Efficacy of Cathodal Transcranial Direct Current Stimulation Over the Left Orbitofrontal Cortex in a Patient With Treatment-Resistant Obsessive-Compulsive Disorder.

Obsessive-compulsive disorder (OCD) is a disabling and frequent neuropsychiatric disorder. Forty percent to 60% of patients with OCD fail to respond to available treatments. Neuroimaging studies have highlighted an association between the severity of obsessive and compulsive symptoms and an increased activity of the left orbitofrontal cortex (OFC) in patients with OCD. Transcranial direct current stimulation (tDCS) is a powerful and easy-to-use tool to modulate brain activity. Cathodal tDCS (c-tDCS) is assumed to decrease cortical excitability in the targeted brain region. We hypothesized that c-tDCS applied over the left OFC alleviates symptoms in patients with treatment-resistant OCD. We report here the case of a patient who received 10 sessions (2 mA, 20 minutes) of c-tDCS. The tDCS sessions were delivered twice a day with a 2-hour interval, with the cathode (35 cm²) placed over the left OFC and the anode (100 cm²) placed over the contralateral occipital region. No adverse event was reported. One month after the completion of the tDCS sessions, we observed a 26% reduction in severity of obsessive and compulsive symptoms measured using the Yale-Brown Obsessive Compulsive Scale scores. These findings are consistent with a previous study reporting a similar reduction in obsessive and compulsive symptoms after a low-frequency repetitive transcranial magnetic stimulation was given to the left OFC. Our results indicate that c-tDCS applied over the left OFC may be a suitable and safe treatment in patients with treatment-resistant OCD.