Stress priming transcranial direct current stimulation (tDCS) enhances updating of emotional content in working memory.

Transcranial direct current stimulation (tDCS) targeting the prefrontal cortex has emerged as a valuable tool in psychiatric research. Understanding the impact of affective states, such as stress at the time of stimulation, on the efficacy of prefrontal tDCS is crucial for advancing tDCS interventions. Stress-primed tDCS, wherein stress is used as a priming agent, has the potential to modulate neural plasticity and enhance cognitive functions, particularly in emotional working memory. However, prior research using stress-primed tDCS focused solely on non-emotional working memory performance, yielding mixed results. In this sham-controlled study, we addressed this gap by investigating the effects of stress-primed bifrontal tDCS (active versus sham) on both non-emotional and emotional working memory performance. The study was conducted in 146 healthy individuals who were randomly assigned to four experimental groups. The Trier Social Stress Test (TSST) or a control variant of the test was used to induce a stress versus control state. The results showed that stress priming significantly enhanced the effects of tDCS on the updating of emotional content in working memory, as evidenced by improved accuracy. Notably, no significant effects of stress priming were found for non-emotional working memory performance. These findings highlight the importance of an individual's prior affective state in shaping their response to tDCS, especially in the context of emotional working memory.

Dose-dependent response of prefrontal transcranial direct current stimulation on the heart rate variability: An electric field modeling study.

Transcranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) modulates the autonomic nervous system by activating deeper brain areas via top-down pathway. However, effects on the nervous system are heterogeneous and may depend on the amount of current that penetrates. Therefore, we aimed to investigate the variable effects of tDCS on heart rate variability (HRV), a measure of the functional state of the autonomic nervous system. Using three prefrontal tDCS protocols (1.5, 3 mA and sham), we associated the simulated individual electric field (E-field) magnitude in brain regions of interest with the HRV effects. This was a randomized, double-blinded, sham-controlled and within-subject trial, in which healthy young-adult participants received tDCS sessions separated by 2 weeks. The brain regions of interest were the dorsolateral PFC (DLPFC), anterior cingulate cortex, insula and amygdala. Overall, 37 participants were investigated, corresponding to a total of 111 tDCS sessions. The findings suggested that HRV, measured by root mean squared of successive differences (RMSSD) and high-frequency HRV (HF-HRV), were significantly increased by the 3.0 mA tDCS when compared to sham and 1.5 mA. No difference was found between sham and 1.5 mA. E-field analysis showed that all brain regions of interest were associated with the HRV outcomes. However, this significance was associated with the protocol intensity, rather than inter-individual brain structural variability. To conclude, our results suggest a dose-dependent effect of tDCS for HRV. Therefore, further research is warranted to investigate the optimal current dose to modulate HRV.

Home-Use Transcranial Direct Current Stimulation for the Treatment of a Major Depressive Episode: A Randomized Clinical Trial.

Importance: Transcranial direct current stimulation (tDCS) is moderately effective for depression when applied by trained staff. It is not known whether self-applied tDCS, combined or not with a digital psychological intervention, is also effective. Objective: To determine whether fully unsupervised home-use tDCS, combined with a digital psychological intervention or digital placebo, is effective for a major depressive episode. Design, Setting, and Participants: This was a double-blinded, sham-controlled, randomized clinical trial with 3 arms: (1) home-use tDCS plus a digital psychological intervention (double active); (2) home-use tDCS plus digital placebo (tDCS only), and (3) sham home-use tDCS plus digital placebo (double sham). The study was conducted between April 2021 and October 2022 at participants' homes and at Instituto de Psiquiatria do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil. Included participants were aged 18 to 59 years with major depression and a Hamilton Depression Rating Scale, 17-item version (HDRS-17), score above 16, a minimum of 8 years of education, and access to a smartphone and internet at home. Exclusion criteria were other psychiatric disorders, except for anxiety; neurologic or clinical disorders; and tDCS contraindications. Interventions: tDCS was administered in 2-mA, 30-minute prefrontal sessions for 15 consecutive weekdays (1-mA, 90-second duration for sham) and twice-weekly sessions for 3 weeks. The digital intervention consisted of 46 sessions based on behavioral therapy. Digital placebo was internet browsing. Main Outcomes and Measures: Change in HDRS-17 score at week 6. Results: Of 837 volunteers screened, 210 participants were enrolled (180 [86%] female; mean [SD] age, 38.9 [9.3] years) and allocated to double active (n = 64), tDCS only (n = 73), or double sham (n = 73). Of the 210 participants enrolled, 199 finished the trial. Linear mixed-effects models did not reveal statistically significant group differences in treatment by time interactions for HDRS-17 scores, and the estimated effect sizes between groups were as follows: double active vs tDCS only (Cohen d, 0.05; 95% CI, -0.48 to 0.58; P = .86), double active vs double sham (Cohen d, -0.20; 95% CI, -0.73 to 0.34; P = .47), and tDCS only vs double sham (Cohen d, -0.25; 95% CI, -0.76 to 0.27; P = .35). Skin redness and heat or burning sensations were more frequent in the double active and tDCS only groups. One nonfatal suicide attempt occurred in the tDCS only group. Conclusions and Relevance: Unsupervised home-use tDCS combined with a digital psychological intervention or digital placebo was not found to be superior to sham for treatment of a major depressive episode in this trial. Trial Registration: ClinicalTrials.gov Identifier: NCT04889976.

Incidence of Suicidal Ideation in a Civil Servants Cohort During the COVID-19 Pandemic in Brazil: Insights from the ELSA-Brasil Study.

OBJECTIVE: This study investigated the incidence of suicidal ideation and its associated risk factors in the São Paulo state of ELSA-Brasil cohort during the COVID-19 pandemic. METHODS: During a pre-pandemic ELSA-Brasil onsite assessment in 2016-2018 (wave 3) and a pandemic online assessment in May-July 2020 (wave COVID), we assessed suicidal ideation using the Clinical Interview Scheduled-Revised (CIS-R). Single and multi predictor logistic regressions were performed using sociodemographic characteristics, household finance impact during pandemic, presence of previous chronic diseases, alcohol abuse, adverse childhood experiences (ACE), living alone, and previous CMD as predictors. Suicidal ideation incidence was used as outcome. RESULTS: Out of 4191 participants of wave 3, 2117 (50.5%) answered wave COVID. There was a threefold increase in suicide ideation, from 34 (1.8%) to 104 (5.6%).In multiple predictor models, we found that previous CMD (OR 7.17; 95% CI 4.43 - 11.58) and ACE (OR 1.72; 95% CI 1.09 - 2.72) increased the odds of incident suicidal ideation. The sociodemographic predictors female sex, younger age and low income were significant risk factors only in the single predictor model. Conclusions These findings underscore the importance of monitoring and supporting individuals who suffered ACE and have a history of mental health disorders. This is especially critical in times of heightened societal stress, such as the COVID-19 pandemic. CONCLUSIONS: These findings underscore the importance of monitoring and supporting individuals who suffered ACE and have a history of mental health disorders. This is especially critical in times of heightened societal stress, such as the COVID-19 pandemic.

Vagally-mediated HRV as a marker of trait rumination in healthy individuals? A large cross-sectional analysis.

The tendency to ruminate (i.e., repetitive, self-referential, negative thoughts) is a maladaptive form of emotional regulation and represents a transdiagnostic vulnerability factor for stress-related psychopathology. Vagally-mediated heart rate variability (vmHRV) provides a non-invasive, surrogate measure of vagal modulation of the heart, and higher HRV is considered an indicator of susceptibility, or ability to respond to stress. Past research has suggested a link between trait rumination and vmHRV; however, inconsistent results exist in healthy individuals. In this study, we investigated the association between the tendency to ruminate, brooding, and reflection (using the Ruminative Response Scale) with vmHRV measured at baseline in a healthy population using a large cross-sectional dataset (N = 1189, 88% female; mean age = 21.55, ranging from 17 to 48 years old), which was obtained by combining samples of healthy individuals from different studies from our laboratory. The results showed no cross-sectional correlation between vmHRV and trait rumination (confirmed by Bayesian analysis), even after controlling for important confounders such as gender, age, and depressive symptoms. Also, a non-linear relationship was rejected. In summary, based on our results in a large sample of healthy individuals, vmHRV is not a marker of trait rumination (as measured by the Ruminative Response Scale).

Investigating the variability of prefrontal tDCS effects on working memory: An individual E-field distribution study.

Transcranial direct current stimulation (tDCS) over the prefrontal cortex has the potential to enhance working memory by means of a weak direct current applied to the scalp. However, its effects are highly variable and possibly dependent on individual variability in cortical architecture and head anatomy. Unveiling sources of heterogeneity might improve fundamental and clinical application of tDCS in the field. Therefore, we investigated sources of tDCS variability of prefrontal 1.5 mA tDCS, 3 mA tDCS and sham tDCS in 40 participants (67.5% women, mean age 24.7 years) by associating simulated electric field (E-field) magnitude in brain regions of interest (dorsolateral prefrontal cortex, anterior cingulate cortex (ACC) and subgenual ACC) and working memory performance. Emotional and non-emotional 3-back paradigms were used. In the tDCS protocol analysis, effects were only significant for the 3 mA group, and only for the emotional tasks. In the individual E-field magnitude analysis, faster responses in non-emotional, but not in the emotional task, were associated with stronger E-fields in all brain regions of interest. Concluding, individual E-field distribution might explain part of the variability of prefrontal tDCS effects on working memory performance and in clinical samples. Our results suggest that tDCS effects might be more consistent or improved by applying personalizing current intensity, although this hypothesis should be confirmed by further studies.

Prefrontal transcranial direct current stimulation over the right prefrontal cortex reduces proactive and reactive control performance towards emotional material in healthy individuals

The prefrontal cortex plays a crucial role in cognitive processes, both during anticipatory and reactive modes of cognitive control. Transcranial Direct Current Stimulation (tDCS) can modulate these cognitive resources. However, there is a lack of research exploring the impact of tDCS on emotional material processing in the prefrontal cortex, particularly in regard to proactive and reactive modes of cognitive control. In this study, 35 healthy volunteers underwent both real and sham tDCS applied to the right prefrontal cortex in a counterbalanced order, and then completed the Cued Emotion Control Task (CECT). Pupil dilation, a measure of cognitive resource allocation, and behavioral outcomes, such as reaction time and accuracy, were collected. The results indicate that, as compared to sham stimulation, active right-sided tDCS reduced performance and resource allocation in both proactive and reactive modes of cognitive control. These findings highlight the importance of further research on the effects of tDCS applied to the right prefrontal cortex on cognitive engagement, particularly for clinical trials utilizing the present electrode montage in combination with cognitive interventions. (AU)

An electric field modeling study with meta-analysis to understand the antidepressant effects of transcranial direct current stimulation (tDCS)

Objective: Transcranial direct current stimulation (tDCS) has mixed effects for major depressive disorder (MDD) symptoms, partially owing to large inter-experimental variability in tDCS protocols and their correlated induced electric fields (E-fields). We investigated whether the E-field strength of distinct tDCS parameters was associated with antidepressant effect. Methods: A meta-analysis was performed with placebo-controlled clinical trials of tDCS enrolling MDD patients. PubMed, EMBASE, and Web of Science were searched from inception to March 10, 2023. Effect sizes of tDCS protocols were correlated with E-field simulations (SimNIBS) of brain regions of interest (bilateral dorsolateral prefrontal cortex [DLPFC] and bilateral subgenual anterior cingulate cortex [sgACC]). Moderators of tDCS responses were also investigated. Results: A total of 20 studies were included (21 datasets, 1,008 patients), using 11 distinct tDCS protocols. Results revealed a moderate effect for MDD (g = 0.41, 95%CI 0.18-0.64), while cathode position and treatment strategy were found to be moderators of response. A negative association between effect size and tDCS-induced E-field magnitude was seen, with stronger E-fields in the right frontal and medial parts of the DLPFC (targeted by the cathode) leading to smaller effects. No association was found for the left DLPFC and the bilateral sgACC. An optimized tDCS protocol is proposed. Conclusions: Our results highlight the need for a standardized tDCS protocol in MDD clinical trials. Registration number: PROSPERO CRD42022296246.

Brain stimulation for treatment-resistant depression.

Depression is one of the main public health problems in the world, having a high prevalence and being considered the main cause of disability. An important portion of patients does not respond to treatment with the initial trial of conventional antidepressants in the current depressive episode of moderate to severe intensity, which characterizes treatment-resistant depression. In this context, non-invasive neuromodulation procedures use an electric current or magnetic field to modulate the central nervous system, and they represent a new option for patients with treatment-resistant depression.

Evidence-based umbrella review of non-invasive brain stimulation in anxiety disorders

Background and objectives Although several meta-analyses have suggested the efficacy of non-invasive brain stimulation (NIBS) mainly in prefrontal brain areas to treat mental disorders, no synthetic approach has been performed for other psychiatric disorders rather than depression. The objective is to assess the available evidence of NIBS in the treatment of anxiety disorders. Methods An umbrella review (CRD42021239577) was performed only looking for reviews with meta-analyses of randomized clinical trials using a source strategy MeSH keywords in MEDLINE through Pubmed by two independent researchers. The effects of different methods of NIBS in anxiety disorders were assessed using the PICO strategy. The methodological quality was evaluated using AMSTAR-2 and certainty of evidence using the GRADE-pro framework. Results From 136 screening meta-analyses, 16 from 14 studies were included in the final analysis. Generalized Anxiety Disorder (GAD) and Obsessive Compulsive Disorder (OCD) respond best to low frequency repetitive transcranial magnetic stimulation (rTMS), while Posttraumatic Stress Disorder (PTSD) has the largest effect size at high frequency rTMS. Panic Disorder (PD) has no evidence for clinical use of NIBS. There were not identified meta-analyses about other anxiety disorders. In general, the included studies had good methodological quality, but low to moderate evidence for clinical recommendation. Conclusion Available evidence reveals NIBS as an effective and safe approach to treat GAD, PTSD and OCD with low recommendation level to clinical application. A great heterogeneity of studies indicates the necessity to develop new randomized clinical trials applying NIBS to treat those and other mental disorders. (AU)

An electric field modeling study with meta-analysis to understand the antidepressant effects of transcranial direct current stimulation (tDCS).

OBJECTIVE: Transcranial direct current stimulation (tDCS) has mixed effects for major depressive disorder (MDD) symptoms, partially owing to large inter-experimental variability in tDCS protocols and their correlated induced electric fields (E-fields). We investigated whether the E-field strength of distinct tDCS parameters was associated with antidepressant effect. METHODS: A meta-analysis was performed with placebo-controlled clinical trials of tDCS enrolling MDD patients. PubMed, EMBASE, and Web of Science were searched from inception to March 10, 2023. Effect sizes of tDCS protocols were correlated with E-field simulations (SimNIBS) of brain regions of interest (bilateral dorsolateral prefrontal cortex [DLPFC] and bilateral subgenual anterior cingulate cortex [sgACC]). Moderators of tDCS responses were also investigated. RESULTS: A total of 20 studies were included (21 datasets, 1,008 patients), using 11 distinct tDCS protocols. Results revealed a moderate effect for MDD (g = 0.41, 95%CI 0.18-0.64), while cathode position and treatment strategy were found to be moderators of response. A negative association between effect size and tDCS-induced E-field magnitude was seen, with stronger E-fields in the right frontal and medial parts of the DLPFC (targeted by the cathode) leading to smaller effects. No association was found for the left DLPFC and the bilateral sgACC. An optimized tDCS protocol is proposed. CONCLUSION: Our results highlight the need for a standardized tDCS protocol in MDD clinical trials.

Time-course of the tDCS antidepressant effect: An individual participant data meta-analysis.

INTRODUCTION: Prefrontal transcranial direct current stimulation (tDCS) shows promise as an effective treatment for depression. However, factors influencing treatment and the time-course of symptom improvements remain to be elucidated. METHODS: Individual participant data was collected from ten randomised controlled trials of tDCS in depression. Depressive symptom scores were converted to a common scale, and a linear mixed effects individual growth curve model was fit to the data using k-fold cross-validation to prevent overfitting. RESULTS: Data from 576 participants were analysed (tDCS: n = 311; sham: n = 265), of which 468 were unipolar and 108 had bipolar disorder. tDCS effect sizes reached a peak at approximately 6 weeks, and continued to diverge from sham up to 10 weeks. Significant predictors associated with worse response included higher baseline depression severity, treatment resistance, and those associated with better response included bipolar disorder and anxiety disorder. CONCLUSIONS: Our findings suggest that longer treatment courses, lasting at least 6 weeks in duration, may be indicated. Further, our results show that tDCS is effective for depressive symptoms in bipolar disorder. Compared to unipolar depression, participants with bipolar disorder may require additional maintenance sessions to prevent rapid relapse.

Prefrontal transcranial direct current stimulation over the right prefrontal cortex reduces proactive and reactive control performance towards emotional material in healthy individuals.

The prefrontal cortex plays a crucial role in cognitive processes, both during anticipatory and reactive modes of cognitive control. Transcranial Direct Current Stimulation (tDCS) can modulate these cognitive resources. However, there is a lack of research exploring the impact of tDCS on emotional material processing in the prefrontal cortex, particularly in regard to proactive and reactive modes of cognitive control. In this study, 35 healthy volunteers underwent both real and sham tDCS applied to the right prefrontal cortex in a counterbalanced order, and then completed the Cued Emotion Control Task (CECT). Pupil dilation, a measure of cognitive resource allocation, and behavioral outcomes, such as reaction time and accuracy, were collected. The results indicate that, as compared to sham stimulation, active right-sided tDCS reduced performance and resource allocation in both proactive and reactive modes of cognitive control. These findings highlight the importance of further research on the effects of tDCS applied to the right prefrontal cortex on cognitive engagement, particularly for clinical trials utilizing the present electrode montage in combination with cognitive interventions.

A pandemic toll in frail older adults: Higher odds of incident and persistent common mental disorders in the ELSA-Brasil COVID-19 mental health cohort.

INTRODUCTION: We aimed to investigate the association of frailty with persistent and incident common mental disorders (CMD) in older adults during the pandemic. METHODS: We included 706 older adults who participated in the onsite wave of the ELSA-Brasil study (2017-2019) and the online COVID-19 assessment (May-July 2020). CMD were assessed in both waves by the Clinical Interview Schedule-Revised. Frailty was defined according to the physical phenotype and Frailty Index in the 2017-2019 wave. Logistic regression was used to investigate the association of frailty with persistent and incident CMD, adjusted for sociodemographics. RESULTS: Frailty according to both definitions were associated with persistent CMD (Frailty Index: OR = 8.61, 95 % CI = 4.08-18.18; physical phenotype: OR = OR = 23.67, 95 % CI = 7.08-79.15), and incident CMD (Frailty Index: OR = 2.79, 95 % CI = 1.15-6.78; physical phenotype OR = 4.37, 95 % CI = 1.31-14.58). The exclusion of exhaustion (that overlaps with psychiatric symptoms) from the frailty constructs did not change the association between frailty and persistent CMD, although the associations with indent CMD were no longer significant. LIMITATIONS: Fluctuations in CMD status were not captured between both assessments. CONCLUSION: Frailty status before the COVID-19 outbreak was associated with higher odds of persistent and incident CMD in older adults during the pandemic first wave. Identifying individuals at higher risk of mental burden can help prioritize resources allocation and management.

Transcranial direct current stimulation versus intermittent theta-burst stimulation for the improvement of working memory performance

Non-invasive brain stimulation (NIBS) techniques have been increasingly used over the dorsolateral prefrontal cortex (DLPFC) to enhance working memory (WM) performance. Notwithstanding, NIBS protocols have shown either small or inconclusive cognitive effects on healthy and neuropsychiatric samples. Therefore, we assessed working memory performance and safety of transcranial direct current stimulation (tDCS), intermittent theta-burst stimulation (iTBS), and both therapies combined vs placebo over the neuronavigated left DLPFC of healthy participants. Twenty-four subjects were included to randomly undergo four sessions of NIBS, once a week: tDCS alone, iTBS alone, combined interventions and placebo. The 2-back task and an adverse effect scale were applied after each NIBS session. Results revealed a significantly faster response for iTBS (b= -21.49, p= 0.04), but not for tDCS and for the interaction tDCS vs. iTBS (b= 13.67, p= 0.26 and b= 40.5, p= 0.20, respectively). No changes were observed for accuracy and no serious adverse effects were found among protocols. Although tolerable, an absence of synergistic effects for the combined protocol was seen. Nonetheless, future trials accessing different outcomes for the combined protocols, as well as studies investigating iTBS over the left DLPFC for cognition and exploring sources of variability for tDCS are encouraged. (AU)

Prevalence and risk factors of psychiatric symptoms and diagnoses before and during the COVID-19 pandemic: findings from the ELSA-Brasil COVID-19 mental health cohort.

BACKGROUND: There is mixed evidence on increasing rates of psychiatric disorders and symptoms during the coronavirus disease 2019 (COVID-19) pandemic in 2020. We evaluated pandemic-related psychopathology and psychiatry diagnoses and their determinants in the Brazilian Longitudinal Study of Health (ELSA-Brasil) São Paulo Research Center. METHODS: Between pre-pandemic ELSA-Brasil assessments in 2008-2010 (wave-1), 2012-2014 (wave-2), 2016-2018 (wave-3) and three pandemic assessments in 2020 (COVID-19 waves in May-July, July-September, and October-December), rates of common psychiatric symptoms, and depressive, anxiety, and common mental disorders (CMDs) were compared using the Clinical Interview Scheduled-Revised (CIS-R) and the Depression Anxiety Stress Scale-21 (DASS-21). Multivariable generalized linear models, adjusted by age, gender, educational level, and ethnicity identified variables associated with an elevated risk for mental disorders. RESULTS: In 2117 participants (mean age 62.3 years, 58.2% females), rates of CMDs and depressive disorders did not significantly change over time, oscillating from 23.5% to 21.1%, and 3.3% to 2.8%, respectively; whereas rate of anxiety disorders significantly decreased (2008-2010: 13.8%; 2016-2018: 9.8%; 2020: 8%). There was a decrease along three wave-COVID assessments for depression [ß = -0.37, 99.5% confidence interval (CI) -0.50 to -0.23], anxiety (ß = -0.37, 99.5% CI -0.48 to -0.26), and stress (ß = -0.48, 99.5% CI -0.64 to -0.33) symptoms (all ps < 0.001). Younger age, female sex, lower educational level, non-white ethnicity, and previous psychiatric disorders were associated with increased odds for psychiatric disorders, whereas self-evaluated good health and good quality of relationships with decreased risk. CONCLUSION: No consistent evidence of pandemic-related worsening psychopathology in our cohort was found. Indeed, psychiatric symptoms slightly decreased along 2020. Risk factors representing socioeconomic disadvantages were associated with increased odds of psychiatric disorders.

Transcranial direct current stimulation versus intermittent theta-burst stimulation for the improvement of working memory performance.

Non-invasive brain stimulation (NIBS) techniques have been increasingly used over the dorsolateral prefrontal cortex (DLPFC) to enhance working memory (WM) performance. Notwithstanding, NIBS protocols have shown either small or inconclusive cognitive effects on healthy and neuropsychiatric samples. Therefore, we assessed working memory performance and safety of transcranial direct current stimulation (tDCS), intermittent theta-burst stimulation (iTBS), and both therapies combined vs placebo over the neuronavigated left DLPFC of healthy participants. Twenty-four subjects were included to randomly undergo four sessions of NIBS, once a week: tDCS alone, iTBS alone, combined protocol and placebo. The 2-back task and an adverse effect scale were applied after each NIBS session. Results revealed a significantly faster response for iTBS (b= -21.49, p= 0.04), but not for tDCS and for the interaction tDCS vs. iTBS (b= 13.67, p= 0.26 and b= 40.5, p= 0.20, respectively). No changes were observed for accuracy and no serious adverse effects were found among protocols. Although tolerable, an absence of synergistic effects for the combined protocol was seen. Nonetheless, future trials accessing different outcomes for the combined protocols, as well as studies investigating iTBS over the left DLPFC for cognition and exploring sources of variability for tDCS are encouraged.

Brain Perfusion Alterations Induced by Standalone and Combined Non-Invasive Brain Stimulation over the Dorsolateral Prefrontal Cortex.

Non-invasive brain stimulation (NIBS) interventions are promising for the treatment of psychiatric disorders. Notwithstanding, the NIBS mechanisms of action over the dorsolateral prefrontal cortex (DLPFC), a hub that modulates affective and cognitive processes, have not been completely mapped. We aimed to investigate regional cerebral blood flow (rCBF) changes over the DLPFC and the subgenual anterior cingulate cortex (sgACC) of different NIBS protocols using Single-Photon Emission Computed Tomography (SPECT). A factorial, within-subjects, double-blinded study was performed. Twenty-three healthy subjects randomly underwent four sessions of NIBS applied once a week: transcranial direct current stimulation (tDCS), intermittent theta-burst stimulation (iTBS), combined tDCS + iTBS and placebo. The radiotracer 99m-Technetium-ethylene-cysteine-dimer was injected intravenously during the NIBS session, and SPECT neuroimages were acquired after the session. Results revealed that the combination of tDCS + iTBS increased right sgACC rCBF. Cathodal and anodal tDCS increased and decreased DLPFC rCBF, respectively, while iTBS showed no significant changes compared to the placebo. Our findings suggest that the combined protocol might optimize the activity in the right sgACC and encourage future trials with neuropsychiatric populations. Moreover, mechanistic studies to investigate the effects of tDCS and iTBS over the DLPFC are required.

Transcranial Electrical Stimulation for Psychiatric Disorders in Adults: A Primer.

Transcranial electrical stimulation (tES) comprises noninvasive neuromodulation techniques that deliver low-amplitude electrical currents to targeted brain regions with the goal of modifying neural activities. Expanding evidence from the past decade, specifically using transcranial direct current simulation and transcranial alternating current stimulation, presents promising applications of tES as a treatment for psychiatric disorders. In this review, the authors discuss the basic technical aspects and mechanisms of action of tES in the context of clinical research and practice and review available evidence for its clinical use, efficacy, and safety. They also review recent advancements in use of tES for the treatment of depressive disorders, schizophrenia, substance use disorders, and obsessive-compulsive disorder. Findings largely support growing evidence for the safety and efficacy of tES in the treatment of patients with resistance to existing treatment options, particularly demonstrating promising treatment outcomes for depressive disorders. Future directions of tES research for optimal application in clinical settings are discussed, including the growing home-based, patient-friendly methods and the potential pairing with existing pharmacological or psychotherapeutic treatments for enhanced outcomes. Finally, neuroimaging advancements may provide more specific mapping of brain networks, aiming at more precise tES therapeutic targeting in the treatment of psychiatric disorders.

Examining the impact of the COVID-19 pandemic through the lens of the network approach to psychopathology: Analysis of the Brazilian Longitudinal Study of Health (ELSA-Brasil) cohort over a 12-year timespan.

Cohort studies have displayed mixed findings on changes in mental symptoms severity in 2020, when the COVID-19 pandemic outbreak started. Network approaches can provide additional insights by analyzing the connectivity of such symptoms. We assessed the network structure of mental symptoms in the Brazilian Longitudinal Study of Health (ELSA-Brasil) in 3 waves: 2008-2010, 2017-2019, and 2020, and hypothesized that the 2020 network would present connectivity changes. We used the Clinical Interview Scheduled-Revised (CIS-R) questionnaire to evaluates the severity of 14 common mental symptoms. Networks were graphed using unregularized Gaussian models and compared using centrality and connectivity measures. The predictive power of centrality measures and individual symptoms were also estimated. Among 2011 participants (mean age: 62.1 years, 58% females), the pandemic symptom 2020 network displayed higher overall connectivity, especially among symptoms that were related to general worries, with increased local connectivity between general worries and worries about health, as well as between anxiety and phobia symptoms. There was no difference between 2008 and 2010 and 2017-2019 networks. According to the network theory of mental disorders, external factors could explain why the network structure became more densely connected in 2020 compared to previous observations. We speculate that the COVID-19 pandemic and its innumerous social, economical, and political consequences were prominent external factors driving such changes; although further assessments are warranted.