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The freshwater fish fauna of southern Africa is highly diverse; however, the magnitude of parasitic species they host is unevenly known. The region’s documented adult trematode fish fauna is sparse, while the opposite is evident for intermediate trematode stages. Perceived difficulty in identification of underdeveloped stages lead to the exclusion of reporting metacercariae or lack either morphological or molecular data resulting in a depauperate comparative molecular data repository for species of the region and Africa as a whole. In an effort to address the morphological and molecular data void of the parasite fauna of southern African freshwater fishes, we sought to comprehensively investigate and characterise this fauna. Here we report on three metacercarial forms of Clinostomum (Clinostomidae) from three fish families (Clariidae, Mochokidae, and Mormyridae), provide the first report of a species of the Cryptogonimidae from a cyprinid host in South Africa, and include molecular data for the partial 28S rDNA, ITS1–2 and COI mtDNA regions of these metacercarial forms. Our clinostomid specimens morphologically and genetically corresponded with Clinostomum brieni (e.g., Clarias gariepinus) and Clinostomum ‘morphotype 2’ and ‘morphotype 3’ per Caffara et al. (2017) from the mormyrid Marcusenius pongolensis and the mochokid catfish Chiloglanis sp., respectively. Our cryptogonimid metacercariae did not correspond with any known species or available molecular sequence data; however, the presence of robust circumoral spines on the oral sucker indicated that they are either a species of Acanthostomum or Proctocaecum. The molecular data we provide are the first for an Acanthostomum/Proctocaecum-type cryptogonimid from Africa.
There is growing evidence that smoking increases the risk of developing psychiatric disorders, but the underlying mechanisms are largely unknown. We examine brain structure as a potential pathway between smoking and psychiatric disease liability.
Methods
We test associations between smoking (initiation, cigarettes per day, cessation, lifetime use) and depression, bipolar disorder, and schizophrenia, with and without correcting for volume of the amygdala, hippocampus, lateral and medial orbitofrontal cortex, superior frontal context, and cortical thickness and surface area. We use three methods that use summary statistics of genome-wide association studies to investigate genome-wide and local genetic overlap (genomic structural equation modeling, local analysis of (co)variant association), as well as causal associations (Mendelian randomization).
Results
While we find causal effects of smoking on brain volume in different brain areas, and with psychiatric disorders, brain volume did not seem to mediate the effect of smoking on psychiatric disorders.
Conclusions
While these findings are limited by characteristics of the included summary statistics (e.g. sample size), we conclude that brain volume of these areas is unlikely to explain a substantial part of any effect of smoking on psychiatric disorders. Nevertheless, genetic methods are valuable tools for exploring other potential mechanisms, such as brain functional connectivity, foregoing the need to collect all phenotypes in one dataset.
It remains unclear which individuals with subthreshold depression benefit most from psychological intervention, and what long-term effects this has on symptom deterioration, response and remission.
Aims
To synthesise psychological intervention benefits in adults with subthreshold depression up to 2 years, and explore participant-level effect-modifiers.
Method
Randomised trials comparing psychological intervention with inactive control were identified via systematic search. Authors were contacted to obtain individual participant data (IPD), analysed using Bayesian one-stage meta-analysis. Treatment–covariate interactions were added to examine moderators. Hierarchical-additive models were used to explore treatment benefits conditional on baseline Patient Health Questionnaire 9 (PHQ-9) values.
Results
IPD of 10 671 individuals (50 studies) could be included. We found significant effects on depressive symptom severity up to 12 months (standardised mean-difference [s.m.d.] = −0.48 to −0.27). Effects could not be ascertained up to 24 months (s.m.d. = −0.18). Similar findings emerged for 50% symptom reduction (relative risk = 1.27–2.79), reliable improvement (relative risk = 1.38–3.17), deterioration (relative risk = 0.67–0.54) and close-to-symptom-free status (relative risk = 1.41–2.80). Among participant-level moderators, only initial depression and anxiety severity were highly credible (P > 0.99). Predicted treatment benefits decreased with lower symptom severity but remained minimally important even for very mild symptoms (s.m.d. = −0.33 for PHQ-9 = 5).
Conclusions
Psychological intervention reduces the symptom burden in individuals with subthreshold depression up to 1 year, and protects against symptom deterioration. Benefits up to 2 years are less certain. We find strong support for intervention in subthreshold depression, particularly with PHQ-9 scores ≥ 10. For very mild symptoms, scalable treatments could be an attractive option.
The description and delineation of trematode species is a major ongoing task. Across the field there has been, and currently still is, great variation in the standard of this work and in the sophistication of the proposal of taxonomic hypotheses. Although most species are relatively unambiguously distinct from their congeners, many are either morphologically very similar, including the major and rapidly growing component of cryptic species, or are highly variable morphologically despite little to no molecular variation for standard DNA markers. Here we review challenges in species delineation in the context provided to us by the historical literature, and the use of morphological, geographical, host, and molecular data. We observe that there are potential challenges associated with all these information sources. As a result, we encourage careful proposal of taxonomic hypotheses with consideration for underlying species concepts and frank acknowledgement of weaknesses or conflict in the data. It seems clear that there is no single source of data that provides a wholly reliable answer to our taxonomic challenges but that nuanced consideration of information from multiple sources (the ‘integrated approach’) provides the best possibility of developing hypotheses that will stand the test of time.
An important contributor to the decreased life expectancy of individuals with schizophrenia is sudden cardiac death. Arrhythmic disorders may play an important role herein, but the nature of the relationship between schizophrenia and arrhythmia is unclear.
Aims
To assess shared genetic liability and potential causal effects between schizophrenia and arrhythmic disorders and electrocardiogram (ECG) traits.
Method
We leveraged summary-level data of large-scale genome-wide association studies of schizophrenia (53 386 cases, 77 258 controls), arrhythmic disorders (atrial fibrillation, 55 114 cases, 482 295 controls; Brugada syndrome, 2820 cases, 10 001 controls) and ECG traits (heart rate (variability), PR interval, QT interval, JT interval and QRS duration, n = 46 952–293 051). We examined shared genetic liability by assessing global and local genetic correlations and conducting functional annotation. Bidirectional causal relations between schizophrenia and arrhythmic disorders and ECG traits were explored using Mendelian randomisation.
Results
There was no evidence for global genetic correlation, except between schizophrenia and Brugada syndrome (rg = 0.14, 95% CIs = 0.06–0.22, P = 4.0E−04). In contrast, strong positive and negative local correlations between schizophrenia and all cardiac traits were found across the genome. In the most strongly associated regions, genes related to immune and viral response mechanisms were overrepresented. Mendelian randomisation indicated that liability to schizophrenia causally increases Brugada syndrome risk (beta = 0.14, CIs = 0.03–0.25, P = 0.009) and heart rate during activity (beta = 0.25, CIs = 0.05–0.45, P = 0.015).
Conclusions
Despite little evidence for global genetic correlation, specific genomic regions and biological pathways emerged that are important for both schizophrenia and arrhythmia. The putative causal effect of liability to schizophrenia on Brugada syndrome warrants increased cardiac monitoring and early medical intervention in people with schizophrenia.
Many autistic people in mental health are suicidal. This study evaluated the effectiveness of dialectical behavior therapy (DBT) v. treatment as usual (TAU) in reducing suicidal ideation and suicide attempts.
Methods
At six Dutch mental health centers, 123 outpatients (18–65 years) with DSM-5 diagnosed autism spectrum disorder (ASD) and suicidal behavior were randomly assigned to the DBT intervention group (n = 63) or TAU control group (n = 60). Assessments were conducted at baseline, post-treatment at 6 months and 12-month follow-up. The primary outcomes were severity of suicidal ideation and frequency of suicide attempts. The severity of depression and social anxiety were secondary outcomes.
Results
At end-of-treatment, DBT significantly reduced both suicidal ideation (z = −2.24; p = 0.025; b = −4.41; s.e. = 197.0) and suicide attempts (z = −3.15; p = 0.002; IRR = 0.046; s.e. = 0.045) compared to TAU, but lost statistical significance at the 12-month follow-up. Depression severity significantly decreased with DBT (z = −1.99; p = 0.046: b = −2.74; s.e. = 1.37) remaining so at 12 months (z = −2.46; p = 0.014; b = −3.37; s.e. = 1.37). No effects were observed on social anxiety. Severe adverse events included two suicides in the TAU condition.
Conclusions
DBT is an acceptable, safe, and short-term effective intervention to reduce suicidal ideation and suicide attempts in autistic adults with suicidal behavior.
Cervical dystonia (CD) is a movement disorder characterized by involuntary muscle contractions causing sustained twisting movements and abnormal postures of the neck and head. Assumed affected neuronal regions are the cortico-striatal-thalamo-cortical circuits, which are also involved in cognitive functioning. Indeed, impairments in different cognitive domains have been found in CD patients. However, to date studies have only investigated a limited range of cognitive functions within the same sample. In particular, social cognition (SC) is often missing from study designs. Hence, we aimed to evaluate a broad range of cognitive functions including SC in CD patients.
Method:
In the present study 20 idiopathic CD patients and 40 age-, gender-, and IQ-matched healthy controls (HCs) were assessed with tests for non-SC (verbal memory, psychomotor speed, and executive functions) as well as for SC (emotion recognition, Theory of Mind (ToM), and empathy).
Results:
CD patients scored on average significantly lower than HC on tests for non-SC, but did not show impairments on any of the tests for SC.
Conclusions:
The current study showed impairments in non-SC in CD, but intact social cognitive functions. These results underline the importance of recognizing non-motor symptoms in idiopathic CD patients, but emphasize a focus on identifying strengths and weaknesses in cognitive functioning as these influence daily life activities.
Childhood trauma (CT) may increase vulnerability to psychopathology through affective dysregulation (greater variability, autocorrelation, and instability of emotional symptoms). However, CT associations with dynamic affect fluctuations while considering differences in mean affect levels across CT status have been understudied.
Methods
346 adults (age = 49.25 ± 12.55, 67.0% female) from the Netherlands Study of Depression and Anxiety participated in ecological momentary assessment. Positive and negative affect (PA, NA) were measured five times per day for two weeks by electronic diaries. Retrospectively-reported CT included emotional neglect and emotional/physical/sexual abuse. Linear regressions determined associations between CT and affect fluctuations, controlling for age, sex, education, and mean affect levels.
Results
Compared to those without CT, individuals with CT reported significantly lower mean PA levels (Cohen's d = −0.620) and higher mean NA levels (d = 0.556) throughout the two weeks. CT was linked to significantly greater PA variability (d = 0.336), NA variability (d = 0.353), and NA autocorrelation (d = 0.308), with strongest effects for individuals reporting higher CT scores. However, these effects were entirely explained by differences in mean affect levels between the CT groups. Findings suggested consistency of results in adults with and without lifetime depressive/anxiety disorders and across CT types, with sexual abuse showing the smallest effects.
Conclusions
Individuals with CT show greater affective dysregulation during the two-week monitoring of emotional symptoms, likely due to their consistently lower PA and higher NA levels. It is essential to consider mean affect level when interpreting the impact of CT on affect dynamics.
The Taita Falcon Falco fasciinucha is known to occur and breed at only a few locations in eastern and southern Africa and is currently listed as globally “Vulnerable” and “Critically Endangered” in South Africa. An accurate estimation of its conservation status is however hampered by a lack of data and understanding of the species’ habitat requirements and competitive interactions with congeners. Our aim was to address some of these knowledge gaps. We conducted cliff-nesting raptor surveys across a substantial area of the Mpumalanga/Limpopo escarpment in north-eastern South Africa and modelled habitat suitability for nesting Taita Falcons in relation to the proximity of conspecifics and a community of five other sympatric cliff-nesting raptor species, and in relation to a suite of biotic and abiotic environmental variables. Results suggested the location of Taita Falcon nest sites was negatively associated with distance to the nearest pair of conspecifics and the nearest pair of Lanner Falcons Falco biarmicus, and positively associated with tracts of intact, unfragmented forest and woodland around the base of the cliffs. Our results indicated that Taita Falcon and Lanner Falcon appeared to be responding in opposite ways to a directional change in environmental conditions. This response appeared to be detrimental to Taita Falcon and beneficial to Lanner Falcon. Furthermore, the degradation and destruction of Afrotropical woodland and forest is a documented and ongoing reality, both locally and across much of the Taita Falcon’s global distribution. We argue that our findings are sufficient to justify uplisting Taita Falcon to globally “Endangered”.
Background: Currently, there are no standardized approaches to care or evaluation for tone dysfunction in Canada. The study authors hypothesize that there is significant practice variation across the country. This environmental scan is aimed to describe the current practice for management of patients with hypertonia across Canada. Methods: A web-based survey was developed by the authors with a multi-disciplinary approach and sent to representative rehabilitation sites in each province. All statistical analyses were performed using the R statistical software version 4.0. Results: CP was found to be the most common diagnosis for tone dysfunction, with 58% (7/12) of sites diagnosing greater than 20 new patients per year. All 12 sites offered oral baclofen and gabapentin, and 92% of sites offered trihexyphenidyl. Botulinum toxin injections were offered at 50% of sites. Upper and lower extremity procedures were offered in 83% of the sites. In 8 of 12 sites (67%), patients were seen within a formal multidisciplinary clinic to manage hypertonia. Conclusions: The information gained from this study provides some insight into the current practice across Canada for children with hypertonia. This study may assist in the development of a national, standardized strategy to tone management, potentially facilitating more equitable access to care for patients.
Lifestyle interventions can improve health-related outcomes for people with severe mental illness (SMI), but few studies evaluate this potential in everyday settings. After a successful approach in routine inpatient mental healthcare (MULTI), we sought to replicate this multidisciplinary lifestyle-enhancing support in people with SMI living in sheltered housing (MULTI_sh).
Aims
To evaluate the effectiveness and implementation of MULTI_sh (trial registration: NCT03157557).
Method
In an effectiveness-implementation hybrid cluster-randomised controlled trial, six municipalities with sheltered housing facilities in The Netherlands were randomly assigned to MULTI_sh (n = 3) or treatment as usual (TAU, n = 3). After 12 months, we evaluated effects on metabolic health, sedentary behaviour/physical activity (ActiGraph GT3X+), quality of life (EuroQol 5D, WHOQoL-Bref) and psychopathology (Brief Psychiatric Rating Scale Expanded Version) using multiple regression, adjusting for baseline values and municipalities (intention to treat and per protocol). In addition, implementation fidelity and barriers/facilitators were evaluated (Measurement Instrument for Determinants of Innovation).
Results
Of 177 eligible patients, 74 (42%) could be included in the analyses. Health outcomes did not substantially improve with MULTI_sh (n = 45) compared with TAU (n = 29). MULTI_sh was not implemented as intended. Most patients and all healthcare professionals believed that patients’ lifestyle should be part of treatment, but implementation was primarily (in)directly hindered by organisational factors (e.g. staff shortages, complexity of participation, lack of time and difficulty getting patients involved).
Conclusions
MULTI_sh was not implemented as intended and no clinical health improvements were found. Organisations are decisive in the success or failure of the implementation of lifestyle interventions for people with SMI. More intensive implementation strategies on this level are warranted in sheltered housing.
Group-level studies showed cross-sectional and prospective between-person associations between circadian rest-activity rhythms (RAR), physical activity (PA), sleep, and depressive symptoms. However, whether these associations replicate at the within-person level remains unclear. Therefore, it is clinically relevant to investigate these associations within persons and study whether changes in depressive symptoms are related to changes in circadian rhythm and sleep variables.
Objectives
To identify changes in circadian rhythm elements in proximity to a transition in depressive symptoms, whether changes are less frequent in individuals without compared to those with transitions, and whether there are individual differences in the direction of change of circadian rhythm variables.
Methods
Data of remitted individuals tapering antidepressants were used: 12 with and 14 without a transition in depressive symptoms. RAR, PA, and sleep variables were calculated as predictors from four months of actigraphy data. Transitions in depressive symptoms were based on weekly SCL-90 scores and evaluation interviews. Kernel Change Point analyses were used to detect change points (CPs) and CP timing in circadian rhythm variables for each individual separately.
Results
In 67% of individuals with depressive symptoms transitions, CPs were identified in proximity to symptom transitions. CPs were detected less frequently in the no-transition group with 7 CPs in 14 individuals, compared to transition groups with 10 CPs in 12 individuals. For several RAR and sleep variables, consistent changes were detected in expected directions.
Conclusions
Circadian rhythm variables provide potentially clinically relevant information although their patterns around transitions are highly person-specific. Future research is needed to disentangle which variables are predictive for which patients.
Cognitive deficits may be characteristic for only a subgroup of first-episode psychosis (FEP) and the link with clinical and functional outcomes is less profound than previously thought. This study aimed to identify cognitive subgroups in a large sample of FEP using a clustering approach with healthy controls as a reference group, subsequently linking cognitive subgroups to clinical and functional outcomes.
Methods
204 FEP patients were included. Hierarchical cluster analysis was performed using baseline brief assessment of cognition in schizophrenia (BACS). Cognitive subgroups were compared to 40 controls and linked to longitudinal clinical and functional outcomes (PANSS, GAF, self-reported WHODAS 2.0) up to 12-month follow-up.
Results
Three distinct cognitive clusters emerged: relative to controls, we found one cluster with preserved cognition (n = 76), one moderately impaired cluster (n = 74) and one severely impaired cluster (n = 54). Patients with severely impaired cognition had more severe clinical symptoms at baseline, 6- and 12-month follow-up as compared to patients with preserved cognition. General functioning (GAF) in the severely impaired cluster was significantly lower than in those with preserved cognition at baseline and showed trend-level effects at 6- and 12-month follow-up. No significant differences in self-reported functional outcome (WHODAS 2.0) were present.
Conclusions
Current results demonstrate the existence of three distinct cognitive subgroups, corresponding with clinical outcome at baseline, 6- and 12-month follow-up. Importantly, the cognitively preserved subgroup was larger than the severely impaired group. Early identification of discrete cognitive profiles can offer valuable information about the clinical outcome but may not be relevant in predicting self-reported functional outcomes.
Many adolescents start using tobacco, alcohol, and cannabis. Genetic vulnerability, parent characteristics in young adolescence, and interaction (GxE) and correlation (rGE) between these factors could contribute to the development of substance use. Using prospective data from the TRacking Adolescent Individuals’ Lives Survey (TRAILS; N = 1,645), we model latent parent characteristics in young adolescence to predict young adult substance use. Polygenic scores (PGS) are created based on genome-wide association studies (GWAS) for smoking, alcohol use, and cannabis use. Using structural equation modeling we model the direct, GxE, and rGE effects of parent factors and PGS on young adult smoking, alcohol use, and cannabis initiation. The PGS, parental involvement, parental substance use, and parent–child relationship quality predicted smoking. There was GxE such that the PGS amplified the effect of parental substance use on smoking. There was rGE between all parent factors and the smoking PGS. Alcohol use was not predicted by genetic or parent factors, nor by interplay. Cannabis initiation was predicted by the PGS and parental substance use, but there was no GxE or rGE. Genetic risk and parent factors are important predictors of substance use and show GxE and rGE in smoking. These findings can act as a starting point for identifying people at risk.
Transitions in mental health, such as the onset or sudden progression of psychopathology, are difficult to foresee. If mental health behaves like other complex systems, drops in mental health may be anticipated by early warning signals (EWS), which manifest in the dynamics of time series data.
Objectives
This study aimed to establish the sensitivity and specificity of EWS as personalized risk markers for sudden drops mental health.
Methods
Individuals (N=122, mean age 23.6 ±0.7 years, 57% males) at increased risk for psychopathology completed daily questionnaires on mental states for six consecutive months. Transitions in mental health were identified by change point analyses. EWS, operationalized as rising trends in the autoregressive coefficient of 36 negative mental states, were identified using generalized additive models.
Results
EWS were found for 59% of individuals with a drop in mental health, and for 47% without such a drop (sensitivity: 0-.12; specificity: .88-1). There were considerable individual differences in the prevalence, strength, and timing of EWS.
Conclusions
EWS might be informative of impeding transitions, yet they are also highly conservative. Present findings may inspire future research into the prerequisites for detecting EWS in the context of mental health, for instance with respect to the stability of pre- and post-transition phases, the magnitude of transitions, and the timescale at which EWS manifest. An improved understanding of the dynamics that govern psychopathology could ultimately allow us to determine whether a specific individual at a specific moment in time is at risk for a sudden onset or progression of mental health problems.
This work examines consequences of modelling approximation errors made within the context of the Navier–Stokes–Boussinesq system. Starting from a canonical Boussinesq model, where density fluctuations are allowed to interact with all accelerative terms of the incompressible Navier–Stokes equations in arbitrarily accelerating reference frames, a unified treatment is developed that provides a straightforward way to identify buoyancy forcing associated with gravitational effects, centrifugal forcing associated with frame rotation, as well as centrifugal-type forcing due to variations in flow kinetic energy. The results of the cases studied in inertial, rotating and mixed reference frames demonstrate that in general it may be important to apply buoyancy effects to all non-local accelerative terms, including non-gradient terms such as Coriolis acceleration. Additionally, it is shown that the common practice of ignoring terms representing interaction between density fluctuation and local fluid acceleration can lead to non-negligible error in Boussinesq modelling of highly unsteady flows. These findings have special significance for accurate simulation of flows with density variations in which there may be both background rotation and localised regions of strong swirl, but are also relevant for studies conducted in the inertial frame of reference.
The coronavirus disease 2019 (COVID-19) pandemic has resulted in shortages of personal protective equipment (PPE), underscoring the urgent need for simple, efficient, and inexpensive methods to decontaminate masks and respirators exposed to severe acute respiratory coronavirus virus 2 (SARS-CoV-2). We hypothesized that methylene blue (MB) photochemical treatment, which has various clinical applications, could decontaminate PPE contaminated with coronavirus.
Design:
The 2 arms of the study included (1) PPE inoculation with coronaviruses followed by MB with light (MBL) decontamination treatment and (2) PPE treatment with MBL for 5 cycles of decontamination to determine maintenance of PPE performance.
Methods:
MBL treatment was used to inactivate coronaviruses on 3 N95 filtering facepiece respirator (FFR) and 2 medical mask models. We inoculated FFR and medical mask materials with 3 coronaviruses, including SARS-CoV-2, and we treated them with 10 µM MB and exposed them to 50,000 lux of white light or 12,500 lux of red light for 30 minutes. In parallel, integrity was assessed after 5 cycles of decontamination using multiple US and international test methods, and the process was compared with the FDA-authorized vaporized hydrogen peroxide plus ozone (VHP+O3) decontamination method.
Results:
Overall, MBL robustly and consistently inactivated all 3 coronaviruses with 99.8% to >99.9% virus inactivation across all FFRs and medical masks tested. FFR and medical mask integrity was maintained after 5 cycles of MBL treatment, whereas 1 FFR model failed after 5 cycles of VHP+O3.
Conclusions:
MBL treatment decontaminated respirators and masks by inactivating 3 tested coronaviruses without compromising integrity through 5 cycles of decontamination. MBL decontamination is effective, is low cost, and does not require specialized equipment, making it applicable in low- to high-resource settings.
This study examined the efficacy of attention bias modification training (ABMT) for the treatment of depression.
Methods
In this randomized clinical trial, 145 adults (77% female, 62% white) with at least moderate depression severity [i.e. self-reported Quick Inventory of Depressive Symptomatology (QIDS-SR) ⩾13] and a negative attention bias were randomized to active ABMT, sham ABMT, or assessments only. The training consisted of two in-clinic and three (brief) at-home ABMT sessions per week for 4 weeks (2224 training trials total). The pre-registered primary outcome was change in QIDS-SR. Secondary outcomes were the 17-item Hamilton Depression Rating Scale (HRSD) and anhedonic depression and anxious arousal from the Mood and Anxiety Symptom Questionnaire (MASQ). Primary and secondary outcomes were administered at baseline and four weekly assessments during ABMT.
Results
Intent-to-treat analyses indicated that, relative to assessment-only, active ABMT significantly reduced QIDS-SR and HRSD scores by an additional 0.62 ± 0.23 (p = 0.008, d = −0.57) and 0.74 ± 0.31 (p = 0.021, d = −0.49) points per week. Similar results were observed for active v. sham ABMT: a greater symptom reduction of 0.44 ± 0.24 QIDS-SR (p = 0.067, d = −0.41) and 0.69 ± 0.32 HRSD (p = 0.033, d = −0.42) points per week. Sham ABMT did not significantly differ from the assessment-only condition. No significant differences were observed for the MASQ scales.
Conclusion
Depressed individuals with at least modest negative attentional bias benefitted from active ABMT.
Post-traumatic stress disorder (PTSD), anxiety, and impulsive aggression are linked to transdiagnostic neurocognitive deficits. This includes impaired inhibitory control over inappropriate responses. Prior studies showed that inhibitory control can be improved by modulating the right inferior frontal gyrus (IFG) with transcranial direct current stimulation (tDCS) in combination with inhibitory control training. However, its clinical potential remains unclear. We therefore aimed to replicate a tDCS-enhanced inhibitory control training in a clinical sample and test whether this reduces stress-related mental health symptoms.
Methods
In a preregistered double-blind randomized-controlled trial, 100 active-duty military personnel and post-active veterans with PTSD, anxiety, or impulsive aggression symptoms underwent a 5-session intervention where a stop-signal response inhibition training was combined with anodal tDCS over the right IFG for 20 min at 1.25 mA. Inhibitory control was evaluated with the emotional go/no-go task and implicit association test. Stress-related symptoms were assessed by self-report at baseline, post-intervention, and after 3-months and 1-year follow-ups.
Results
Active relative to sham tDCS neither influenced performance during inhibitory control training nor on assessment tasks, and did also not significantly influence self-reported symptoms of PTSD, anxiety, impulsive aggression, or depression at post-assessment or follow-up.
Conclusions
Our results do not support the idea that anodal tDCS over the right IFG at 1.25 mA enhances response inhibition training in a clinical sample, or that this tDCS-training combination can reduce stress-related symptoms. Applying different tDCS parameters or combining tDCS with more challenging tasks might provide better conditions to modulate cognitive functioning and stress-related symptoms.