Treating auditory hallucinations with transcranial direct current stimulation in a double-blind, randomized trial

Evaluating the effects of tDCS on depressive and anxiety symptoms from a transdiagnostic perspective: a systematic review and meta-analysis of randomized controlled trials

Depressive and anxiety symptoms are prevalent among patients with various clinical conditions, resulting in diminished emotional well-being and impaired daily functioning. The neural mechanisms underlying these symptoms, particularly across different disorders, remain unclear, limiting the effectiveness of conventional treatments. Therefore, it is crucial to elucidate the neural underpinnings of depressive and anxiety symptoms and investigate novel, effective treatments across clinical conditions. Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that can help understand the neural underpinnings of symptoms and facilitate the development of interventions, addressing the two research gaps at both neural and clinical levels. Thus, this systematic review and meta-analysis aims to evaluate the existing evidence regarding the therapeutic efficacy of tDCS in reducing depressive and anxiety symptoms among individuals with diverse clinical diagnoses. This review evaluated evidence from fifty-six randomized, sham-controlled trials that administered repeated tDCS sessions with a parallel design, applying a three-level meta-analytic model. tDCS targeting the left dorsolateral prefrontal cortex (DLPFC) at 2-mA intensity demonstrates moderate efficacy in alleviating depressive symptoms, identifying the left DLPFC as a transdiagnostic neural mechanism of depressive symptoms across clinical conditions. In comparison, the findings on anxiety symptoms demonstrate greater heterogeneity. tDCS over the left DLPFC is effective in reducing depressive symptoms and shows promising effects in alleviating anxiety symptoms among individuals with diverse diagnoses. These findings enhance our understanding of the neuropsychological basis of depressive and anxiety symptoms, laying the groundwork for the development of more effective tDCS interventions applicable across clinical conditions.

Heterogeneous Brain Abnormalities in Schizophrenia Converge on a Common Network Associated With Symptom Remission

BACKGROUND AND HYPOTHESIS

There is a huge heterogeneity of magnetic resonance imaging findings in schizophrenia studies. Here, we hypothesized that brain regions identified by structural and functional imaging studies of schizophrenia could be reconciled in a common network.

STUDY DESIGN

We systematically reviewed the case-control studies that estimated the brain morphology or resting-state local function for schizophrenia patients in the literature. Using the healthy human connectome (n = 652) and a validated technique "coordinate network mapping" to identify a common brain network affected in schizophrenia. Then, the specificity of this schizophrenia network was examined by independent data collected from 13 meta-analyses. The clinical relevance of this schizophrenia network was tested on independent data of medication, neuromodulation, and brain lesions.

STUDY RESULTS

We identified 83 morphological and 60 functional studies comprising 7389 patients with schizophrenia and 7408 control subjects. The "coordinate network mapping" showed that the atrophy and dysfunction coordinates were functionally connected to a common network although they were spatially distant from each other. Taking all 143 studies together, we identified the schizophrenia network with hub regions in the bilateral anterior cingulate cortex, insula, temporal lobe, and subcortical structures. Based on independent data from 13 meta-analyses, we showed that these hub regions were specifically connected with regions of cortical thickness changes in schizophrenia. More importantly, this schizophrenia network was remarkably aligned with regions involving psychotic symptom remission.

CONCLUSIONS

Neuroimaging abnormalities in cross-sectional schizophrenia studies converged into a common brain network that provided testable targets for developing precise therapies.

High-Frequency Transcranial Random Noise Stimulation for Auditory Hallucinations of Schizophrenia: A Case Series

Transcranial electrical stimulation has been proposed as a noninvasive therapeutic approach for reducing treatment-resistant symptoms of schizophrenia-in particular, auditory hallucinations. However, the high variability observed in the clinical response leaves much room to optimize the stimulation parameters and strengthen its benefits. We proposed to investigate the effects of high-frequency transcranial random noise stimulation (hf-tRNS), which is supposed to induce larger effects than conventional direct current stimulation. Here, we present an initial case series of ten patients with schizophrenia who underwent 10 sessions of 20 min hf-tRNS (2 mA, 100-500 Hz, 1 mA offset), with the anode placed over the left dorsolateral prefrontal cortex and the cathode over the left temporoparietal junction. Patients showed a significant reduction in auditory hallucinations after the hf-tRNS sessions (-36.1 +/- 21.8%, p = 0.0059). In this preliminary, open-label study conducted in ten patients with treatment-resistant symptoms of schizophrenia, frontotemporal hf-tRNS was shown to induce a substantial improvement in auditory hallucinations. Additional sham-controlled studies are needed to further evaluate hf-tRNS as a treatment for schizophrenia.

Efficacy of Transcranial Direct Current Stimulation to Improve Insight in Patients With Schizophrenia: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND AND HYPOTHESIS

Impaired insight into the illness and its consequences is associated with poor outcomes in schizophrenia. While transcranial direct current stimulation (tDCS) may represent a potentially effective treatment strategy to relieve various symptoms of schizophrenia, its impact on insight remains unclear. To investigate whether tDCS would modulate insight in patients with schizophrenia, we undertook a meta-analysis based on results from previous RCTs that investigated the clinical efficacy of tDCS. We hypothesize that repeated sessions of tDCS will be associated with insight improvement among patients.

STUDY DESIGN

PubMed and ScienceDirect databases were systematically searched to identify RCTs that delivered at least 10 tDCS sessions in patients with schizophrenia. The primary outcome was the change in insight score, assessed by the Positive and Negative Syndrome Scale (PANSS) item G12 following active tDCS sessions as opposed to sham stimulation. Effect sizes were calculated for all studies and pooled using a random-effects model. Meta-regression and subgroup analyses were conducted.

STUDY RESULTS

Thirteen studies (587 patients with schizophrenia) were included. A significant pooled effect size (g) of -0.46 (95% CI [-0.78; -0.14]) in favor of active tDCS was observed. Age and G12 score at baseline were identified as significant moderators, while change in total PANSS score was not significant.

CONCLUSIONS

Ten sessions of active tDCS with either frontotemporoparietal or bifrontal montage may improve insight into the illness in patients with schizophrenia. The effect of this treatment could contribute to the beneficial outcomes observed in patients following stimulation.

Adjunctive tDCS for treatment-refractory auditory hallucinations in schizophrenia: A meta-analysis of randomized, double-blinded, sham-controlled studies

OBJECTIVE

Treatment-refractory auditory hallucinations (TRAH) in schizophrenia often do not improve with pharmacotherapy. We performed a meta-analysis of randomized, double-blind, sham-controlled clinical trials (RCTs) that systematically examined the therapeutic effects and tolerability of adjunctive active versus sham active transcranial direct current stimulation (tDCS) for auditory hallucinations as measured by the Auditory Hallucination Rating Scale (AHRS) in schizophrenia patients with TRAH.

METHODS

Relevant data were extracted, checked and analyzed using the Review Manager, Version 5.3 by three independent investigators.

RESULTS

Eight double-blind RCTs covering 329 schizophrenia patients (168 in active tDCS group, 161 in sham tDCS group) were included. Although no advantage of active tDCS on auditory hallucinations [7 RCTs, n = 224; standardized mean difference (SMD): - 0.33 (95% confidence interval (CI): - 0.71, 0.05), P = 0.09; I² = 46%] was found compared to sham, subgroup analyses revealed that active tDCS with twice-daily stimulation [6 RCTs, n = 198; SMD: - 0.42 (95%CI: -0.82, -0.02), P = 0.04; I² = 44%] and active tDCS with ≥ 10 stimulation sessions [6 RCTs, n = 198; SMD: - 0.42 (95%CI: -0.82, -0.02), P = 0.04; I² = 44%] showed a significantly better therapeutic effect than sham in improving auditory hallucinations symptoms. Meta-analyses of total psychopathology and discontinuation due to any reason were not significantly different between the active and sham tDCS groups.

CONCLUSION

This meta-analysis demonstrated that the effects of tDCS for auditory hallucinations symptoms were influenced by the tDCS parameters. Twice-daily stimulation and ≥ 10 stimulation sessions may be needed to improve auditory hallucinations symptoms in schizophrenia with TRAH.

Assessment of treatment resistance criteria in non-invasive brain stimulation studies of schizophrenia

Novel treatment modalities, such as non-invasive brain stimulation (NIBS), typically focus on patient groups that have failed multiple treatment interventions. Despite its promise, the clinical translation of NIBS in schizophrenia has been limited. One important obstacle to implementation is the inconsistent reporting of treatment resistance in the clinical trial literature contributing to heterogeneity in reported effects. In response, we develop a numerical approach to synthesize quality of assessment of Treatment-Resistant Schizophrenia (TRS) and apply this to studies investigating therapeutic response to NIBS in patients with schizophrenia. Literature search conducted through PubMed database identified 119 studies investigating Transcranial Magnetic Stimulation and Transcranial Electrical Stimulation in treating resistant schizophrenia symptoms. A quality score out of 11 was assigned to each study based on adherence to the international consensus guidelines for TRS developed by the Treatment Response and Resistance in Psychosis (TRRIP) group. Results revealed an overall paucity of studies with thorough assessment and/or reporting of TRS phenomenon, as evidenced by a mean quality score of 3.38/11 (SD: 1.01) for trials and 5.16/11 (SD: 1.57) for case reports, though this improved minimally since the publication of consensus criteria. Most studies considered treatment-resistance as a single dimensional construct by reporting resistance of a single symptom, and failed to establish treatment adherence, resistance time course and functional impairment. We conclude that the current NIBS literature in schizophrenia do not reflect its true effects on treatment-resistance. There is an urgent need to improve assessment and reporting standards of clinical trials that target TRS.

Potential Locations for Non-Invasive Brain Stimulation in Treating Schizophrenia: A Resting-State Functional Connectivity Analysis

Introduction: Non-invasive brain stimulation (NIBS) techniques have been widely used for the purpose of improving clinical symptoms of schizophrenia. However, the ambiguous stimulation targets may limit the efficacy of NIBS for schizophrenia. Exploring effective stimulation targets may improve the clinical efficacy of NIBS in schizophrenia.

Methods: We first conducted a neurosynth-based meta-analysis of 715 functional magnetic resonance imaging studies to identify schizophrenia-related brain regions as regions of interest. Then, we performed the resting-state functional connectivity analysis in 32 patients with first-episode schizophrenia to find brain surface regions correlated with the regions of interest in three pipelines. Finally, the 10–20 system coordinates corresponding to the brain surface regions were considered as potential targets for NIBS.

Results: We identified several potential targets of NIBS, including the bilateral dorsal lateral prefrontal cortex, supplementary motor area, bilateral inferior parietal lobule, temporal pole, medial prefrontal cortex, precuneus, superior and middle temporal gyrus, and superior and middle occipital gyrus. Notably, the 10-20 system location of the bilateral dorsal lateral prefrontal cortex was posterior to F3 (F4), not F3 (F4).

Conclusion: Conclusively, our findings suggested that the stimulation locations corresponding to these potential targets might help clinicians optimize the application of NIBS therapy in individuals with schizophrenia.

A Literature Mini-Review of Transcranial Direct Current Stimulation in Schizophrenia

Transcranial direct current stimulation (tDCS) is a non-invasive neurostimulation method that utilizes the effect of low-current on brain tissue. In recent years, the effect of transcranial direct current stimulation has been investigated as a therapeutic modality in various neuropsychiatric indications, one of them being schizophrenia. This article aims to provide an overview of the potential application and effect of tDCS in treating patients with schizophrenia. A literature search was performed using the PubMed, Web of Science, and Google Scholar databases for relevant research published from any date until December 2021. Eligible studies included those that used randomized controlled parallel-group design and focused on the use of transcranial direct current stimulation for the treatment of positive, negative, or cognitive symptoms of schizophrenia. Studies were divided into groups based on the focus of research and an overview is provided in separate sections and tables in the article. The original database search yielded 705 results out of which 27 randomized controlled trials met the eligibility criteria and were selected and used for the purpose of this article. In a review of the selected trials, transcranial direct current stimulation is a safe and well-tolerated method that appears to have the potential as an effective modality for the treatment of positive and negative schizophrenic symptoms and offers promising results in influencing cognition. However, ongoing research is needed to confirm these conclusions and to further specify distinct application parameters.

Examining transcranial random noise stimulation as an add-on treatment for persistent symptoms in schizophrenia (STIM'Zo): a study protocol for a multicentre, double-blind, randomized sham-controlled clinical trial

Background

One out of three patients with schizophrenia failed to respond adequately to antipsychotics and continue to experience debilitating symptoms such as auditory hallucinations and negative symptoms. The development of additional therapeutic approaches for these persistent symptoms constitutes a major goal for patients. Here, we develop a randomized-controlled trial testing the efficacy of high-frequency transcranial random noise stimulation (hf-tRNS) for the treatment of resistant/persistent symptoms of schizophrenia in patients with various profiles of symptoms, cognitive deficits and illness duration. We also aim to investigate the biological and cognitive effects of hf-tRNS and to identify the predictors of clinical response.

Methods

In a randomized, double-blind, 2-arm parallel-group, controlled, multicentre study, 144 patients with schizophrenia and persistent symptoms despite the prescription of at least one antipsychotic treatment will be randomly allocated to receive either active (n = 72) or sham (n = 72) hf-tRNS. hf-tRNS (100–500 Hz) will be delivered for 20 min with a current intensity of 2 mA and a 1-mA offset twice a day on 5 consecutive weekdays. The anode will be placed over the left dorsolateral prefrontal cortex and the cathode over the left temporoparietal junction. Patients’ symptoms will be assessed prior to hf-tRNS (baseline), after the 10 sessions, and at 1-, 3- and 6-month follow-up. The primary outcome will be the number of responders defined as a reduction of at least 25% from the baseline scores on the Positive and Negative Syndrome Scale (PANSS) after the 10 sessions. Secondary outcomes will include brain activity and connectivity, source monitoring performances, social cognition, other clinical (including auditory hallucinations) and biological variables, and attitude toward treatment.

Discussion

The results of this trial will constitute a first step toward establishing the usefulness of hf-tRNS in schizophrenia whatever the stage of the illness and the level of treatment resistance. We hypothesize a long-lasting effect of active hf-tRNS on the severity of schizophrenia symptoms as compared to sham. This trial will also have implications for the use of hf-tRNS as a preventive intervention of relapse in patients with schizophrenia.

Trial registration

ClinicalTrials.gov NCT02744989. Prospectively registered on 20 April 2016

Improvement of Insight with Non-Invasive Brain Stimulation in Patients with Schizophrenia: A Systematic Review

Patients with schizophrenia are often unaware of their condition and the consequences of their illness. This lack of insight results in impaired functioning, treatment non-adherence and poor prognosis. Here, we aimed to investigate the effects of non-invasive brain stimulation (NIBS) on two forms of insight, clinical and cognitive, in patients with schizophrenia. We conducted a systematic review of the literature registered in the PROSPERO database (CRD42020220323) according to PRISMA guidelines. The literature search was conducted in Medline and Web of Science databases based on studies published up until October 2020 that included pre-NIBS and post-NIBS measurements of clinical and/or cognitive insight in adults with schizophrenia. A total of 14 studies were finally included, and their methodological quality was assessed by using the QualSyst tool. Despite the lack of well-conducted large randomized-controlled studies using insight as the primary outcome, the available findings provide preliminary evidence that NIBS can improve clinical insight in patients with schizophrenia, with a majority of studies using transcranial direct current stimulation with a left frontotemporal montage. Further studies should investigate the effect of NIBS on insight as a primary outcome and how these effects on insight could translate into clinical and functional benefits in patients with schizophrenia.

Repetitive transcranial magnetic stimulation and transcranial direct current stimulation for auditory hallucinations in schizophrenia: Systematic review and meta-analysis

Through imaging studies, a significant increase in cerebral activity has been detected in fronto-temporal areas in patients experiencing auditory verbal hallucinations. Therefore, non-invasive neuromodulation, in particular transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS), has been considered as a therapeutic intervention for medication-resistant auditory verbal hallucinations in schizophrenia. We aimed to synthesize results from randomized trials on either rTMS or tDCS versus placebo in patients with schizophrenia by including five recently published trials in the field. A systematic review and meta-analysis of relevant literature was conducted. Studies were included on the basis of pre-defined selection criteria. The quality of the studies was assessed by the Cochrane Risk of Bias Tool for Randomized Controlled Trials. RevMan 5.3 was used to conduct the statistical analysis. Including 465 and 960 patients, respectively, 12 tDCS and 27 rTMS studies were included. Regarding treatment of medication refractory auditory verbal hallucinations, no significant effect of tDCS (-0.23 [-0.49, 0.02], p = 0.08) or rTMS (-0.19 [-0.50, 0,11], p = 0.21) was found compared to sham in this meta-analysis. The current study found that it cannot be concluded that rTMS and tDCS are efficacious in treating medication-resistant auditory verbal hallucinations. Larger randomized controlled tDCS trials of a higher quality should be conducted in the future to establish substantial evidence of tDCS. The interventions appear safe and may have beneficial effects on other outcomes.

Concurrent conventional & high-definition transcranial direct current stimulation for treatment of schizophrenia with co-morbid obsessive-compulsive disorder: A case report

Non-invasive brain stimulation techniques such as conventional transcranial direct current stimulation (tDCS) and high definition tDCS (HD-tDCS) are increasingly being used as add-on treatment options in schizophrenia and obsessive-compulsive disorder (OCD). This is reporting of the use of a novel accelerated, symptom-specific, add-on tDCS (combining conventional and high definition) protocol in a patient with both schizophrenia and OCD. The intervention showed clinical utility by reducing both schizophrenia and OCD symptoms.

Cognitive outcomes after tDCS in schizophrenia patients with prominent negative symptoms: Results from the placebo-controlled STARTS trial

Cognitive deficits and negative symptoms in schizophrenia are associated with poor functional outcomes and limited in terms of treatment. The Schizophrenia Treatment With Electric Transcranial Stimulation (STARTS) trial has shown efficacy of transcranial direct current stimulation (tDCS) for improving negative symptoms. In this secondary analysis, we investigate its effects on cognitive performance. In STARTS, a double-blinded, sham-controlled, randomized clinical trial, patients were treated with twice-daily, 20-min, 2-mA fronto-temporal tDCS over 5 days or sham-tDCS. In 90 patients, we evaluated the cognitive performance up to 12 weeks post-treatment. We found that active-tDCS showed no beneficial effects over sham-tDCS in any of the tests. Based on a 5-factor cognitive model, improvements of executive functions and delayed memory were observed in favor of sham-tDCS. Overall, the applied active-tDCS protocol, primarily designed to improve negative symptoms, did not promote cognitive improvement. We discuss possible protocol modification potentially required to increase tDCS effects on cognition. ClinicalTrials.gov identifier: NCT02535676.

Noninvasive direct current stimulation for schizophrenia: a review

PURPOSE OF REVIEW

To provide an update of recent studies describing the effects of transcranial direct current stimulation (tDCS) on patients with schizophrenia, with particular focus on auditory verbal hallucinations (AVH), cognitive deficits, and negative symptoms.

RECENT FINDINGS

As a low-cost, easy-to-use neuromodulation technique, tDCS may have clinical implications for those suffering from treatment-persistent AVH, negative symptoms, and cognitive symptoms in schizophrenia. Over the past decade, tDCS has shown no effects for negative symptoms, except when used at a high frequency of sessions, and inconclusive results for AVH and cognitive symptoms. The treatment has little to no adverse effects.

SUMMARY

The studies reviewed here support the need for further investigation and empirical data regarding the use of tDCS. The underlying mechanisms of tDCS as well as the most effective stimulation parameters must be better understood. Findings support the need for increased duration and frequency of tDCS sessions. One of the next steps is the investigation of effects of concomitant nonpharmacological treatments with tDCS.

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.

Chlorogenic Acid Promotes Autophagy and Alleviates Salmonella Typhimurium Infection Through the lncRNAGAS5/miR-23a/PTEN Axis and the p38 MAPK Pathway

Background

Salmonella typhimurium (ST) causes several intestinal diseases. Polyphenols including chlorogenic acid (CGA) inhibit pathogenesis.

Objective

This study aimed to investigate the mechanisms of CGA in ST infection.

Methods

The intestinal pathological changes and survival rate of ST-infected mice were measured to verify the protection of CGA on ST infection. The antibacterial effects of CGA in vitro on the invasion to intestinal epithelial cells and autophagy was evaluated. The relationships among GAS5, miR-23a, and PTEN were verified. Expression of inflammation- and autophagy-related proteins was detected.

Results

CGA treatment alleviated pathological damage, improved the secretion disturbance of intestinal cytokines caused by ST infection, and reduced the mortality of mice. Intestinal GAS5 was upregulated after CGA treatment. LncRNA GAS5 competitively bound to miR-23a to upregulate PTEN and inhibit the p38 MAPK pathway. CGA regulated the p38 MAPK pathway through lncRNA GAS5/miR-23a/PTEN axis to promote autophagy in ST infection. The functional rescue experiments of miR-23a and PTEN further identified these effects.

Conclusion

CGA promotes autophagy and inhibits ST infection through the GAS5/miR-23a/PTEN axis and the p38 MAPK pathway.

The effects of transcranial direct current stimulation (tDCS) on clinical symptoms in schizophrenia: A systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aims to examine the effects of transcranial direct current stimulation (tDCS) on clinical symptoms in schizophrenia.

METHODS

A literature search was performed for articles published in English using the following databases: MEDLINE, EMBASE, PsycINFO, INSPEC, the Cumulative Index to Nursing & Allied Health Literature Plus (CINAHL Plus), AMED, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, EU Clinical Trials Register, and WHO International Clinical Trials Registry Platform, from their inception to October 2019. The primary outcome variables were the clinical symptoms of schizophrenia including positive symptoms, negative symptoms, and auditory hallucinations.

RESULTS

16 randomized controlled trials (RCTs) were included in the meta-analysis, with a sample of 326 patients with active and with 310 sham tDCS. Active tDCS was found to be more effective in improving positive symptoms [standardized mean difference (SMD) = 0.17; 95 % confidence interval (CI) 0.001 to 0.33], negative symptoms [SMD = 0.43, 95 % CI 0.11, 0.75] and auditory hallucinations [SMD = 0.36 95 % CI 0.02, 0.70]. Subgroup analyses showed better results in cases of pure diagnosis of schizophrenia, higher frequency and more sessions of stimulation.

CONCLUSION

tDCS was effective in improving positive symptoms, negative symptoms and auditory hallucination in schizophrenia. It therefore has potential as a safe and well-tolerated adjunctive intervention for schizophrenia.

Significant improvement in treatment resistant auditory verbal hallucinations after 5 days of double-blind, randomized, sham controlled, fronto-temporal, transcranial direct current stimulation (tDCS): A replication/extension study

BACKGROUND

Transcranial direct current stimulation (tDCS) is a potentially novel treatment for antipsychotic-resistant auditory verbal hallucinations (AVH) in schizophrenia. Nevertheless, results have been mixed across studies.

METHODS

89 schizophrenia/schizoaffective subjects (active: 47; Sham: 42) were randomized to five days of twice-daily 20-min active tDCS vs. sham treatments across two recruitment sites. AVH severity was assessed using the Auditory Hallucination Rating Scale (AHRS) total score. To assess target engagement, MRI was obtained in a sub sample.

RESULTS

We observed a statistically significant, moderate effect-size change in AHRS total score across one-week and one-month favoring active treatment following covariation for baseline symptoms and antipsychotic dose (p = 0.036; d = 0.48). Greatest change was observed on the AHRS loudness item (p = 0.003; d = 0.69). In exploratory analyses, greatest effects on AHRS were observed in patients with lower cognitive symptoms (d = 0.61). In target engagement analysis, suprathreshold mean field-strength (>0.2 V/m) was seen within language-sensitive regions. However, off-target field-strength, which correlated significantly with less robust clinical response, was observed in anterior regions.

CONCLUSIONS

This is the largest study of tDCS for persistent AVH conducted to date. We replicate previous reports of significant therapeutic benefit, but only if medication dosage is considered, with patients receiving lowest medication dosage showing greatest effect. Response was also greatest in patients with lowest levels of cognitive symptoms. Overall, these findings support continued development of tDCS for persistent AVH, but also suggest that response may be influenced by specific patient and treatment characteristics. CLINICALTRIALS.GOV: NCT01898299.

Long-Term Changes in Self-Report Auditory Verbal Hallucinations in Patients with Schizophrenia Using Clozapine

This study explored long-term changes in self-report auditory verbal hallucinations (AVHs) among patients with schizophrenia taking clozapine. Forty-four patients who were evaluated more than twice and were above the mild severity category on the Hamilton Program for Schizophrenia Voices Questionnaire (HPSVQ) were enrolled. The mean observation period was 492.5±350.1 days (median, 452 days). The mean total, physical, and emotional factor scores on the HPSVQ were significantly reduced from baseline to the final observations except for one item "interference with life," which was not significantly reduced. Regarding the time-dependent longitudinal changes modeled using linear mixed-effect regression, the total and physical factor scores showed significant changes during the first year, but the emotional factor score did not satisfy a more stringent level of significance. Female gender was negatively associated with the reduction in total and physical factor scores. The duration of treatment with clozapine also had a negative relationship with the reductions in all three scores.

Auditory verbal hallucinations in schizophrenia: current perspectives in brain stimulation treatments

PURPOSE

This review reports the current perspectives of brain stimulation techniques in the treatment of auditory verbal hallucinations (AVH) in schizophrenia.

METHODS

A systematic search of the literature in the PubMed database revealed that the most studied techniques are noninvasive techniques (NIBS), including electroconvulsive therapy (ECT), transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS).

RESULTS

The results showed that ECT could have great clinical efficacy but is currently underused in practice perhaps due to the costs associated with its limited implementation and potential associated risks. tDCS is still poorly studied and does not demonstrate sufficiently homogeneous or conclusive results yet to prove its efficacy in the treatment of AVH. However, its safe and simple implementation allows us to recommend it to patients who are refractory to other stimulation techniques. Finally, rTMS seems to be the most efficacious NIBS to offer patients with persistent AVH as an add-on therapeutic strategy. Its implementation has a non negligible cost but can be performed by a single practitioner. Great evolution in these techniques with technological progress, robotics and computer science are currently being tested and will undoubtedly improve the clinical efficacy of these procedures, particularly towards more personalized treatments such as individual rTMS targets and intensities. There are also new techniques for deep brain stimulation based on focused ultrasound that could provide much insight into the treatment of AVH in schizophrenia.

CONCLUSION

This review suggests that add-on brain stimulation treatments could play a key role among the therapeutic strategies for auditory hallucinations reduction in schizophrenia.