This clinical trial inestigates the effects of transcranial direct current stimulation (tDCS) on anxiety symptoms in adult women with clinically relevant anxiety levels. The intervention involves the application of low-intensity electrical current over the left dorsolateral prefrontal cortex (DLPFC) across twenty consecutive sessions. Participants are randomly assigned to either an active or sham stimulation group in a double-blind design. The study aims to evaluate changes in anxiety symptoms, emotional regulation, and physiological and molecular markers, including EEG activity, heart rate variability (HRV), and salivary levels of cortisol and interleukin-6 (IL-6) plasma. The findings are expected to support the development of complementary, low-cost, and non-pharmacological strategies for anxiety management.
Anxiety is one of the biggest causes of disability in the world, and many patients do not respond to conventional treatments. Due to this situation, studies were carried out to understand better understand the mechanisms of psychiatric disorders, and one of the alternatives found was the non-invasive brain stimulation with transcranial direct current (tDCS). The project in question aims to evaluate the effectiveness of tDCS-based intervention in adults with anxiety, comparing with a control group. The results will be measured through questionnaires and tests cognitive effects, as well as analyzes of physiological data and inflammatory markers. The study will be done through an experimental and a control group, with 49 men and women in each group. All data will be collected at the Neuromodulation laboratory at Hospital de Clínicas de Porto Alegre, under the coordination of Professor Wolnei Caumo. Participants will be recruited through previously registered patients on Neuromodulation laboratory at Hospital de Clínicas de Porto Alegre database, and the inclusion criteria and exclusion will be defined according to values of anxiety scales and other characteristics of health. The entire process will be conducted safely. Participants in the experimental and control will have their data collected on the first and last day of the intervention. Each participant will receive a placebo or control intervention of 20 sessions, between the first and the last, and will be blinded between groups.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
36
Participants will receive by trained personnel, transcranial direct current stimulation (tDCS) targeting the dorsolateral prefrontal cortex (DLPFC). According to the international 10-20 EEG system, the anodal electrode will be placed over the left F3 position and the cathodal electrode over the right F4 position. Active stimulation will be delivered using a constant current of 2 milliamperes (mA) for 20 minutes per session. The intervention will consist of twelve consecutive daily sessions (Monday to Friday), totaling four week of treatment. A certified tDCS device will be used, programmed to deliver a ramp-up and ramp-down period of 30 seconds. In the sham condition, the same electrode montage will be used; however, the device will automatically ramp down the current after 30 seconds, mimicking the initial tingling sensation without producing lasting neuromodulatory effects. This sham protocol is commonly used to ensure participant blinding in tDCS studies.
Hospital de Clínicas de Porto Alegre
Porto Alegre, Rio Grande do Sul, Brazil
Change in Generalized Anxiety Symptoms as Assessed by the GAD-7 Scale
Change in anxiety symptoms will be assessed by the total change in the GAD-7 score, a 7-item self-administered scale that measures the severity of anxiety symptoms. Scores range from 0 to 21, with higher scores indicating greater anxiety severity.
Time frame: 1 month
Change in the Anxiety Sensitivity Index-Revised (ASI-R) Total Score
The change in anxiety sensitivity will be assessed by the total change in the Anxiety Sensitivity Index-Revised (ASI-R) score, a 36-item questionnaire that measures the fear of anxiety-related sensations. Higher scores indicate greater anxiety sensitivity.
Time frame: 1 month
Change in Pain Intensity as Measured by the Central Sensitization Inventory (CSI) score
The change in pain intensity will be assessed by the Central Sensitization Inventory (CSI), a 25-item self-report questionnaire that assesses common symptoms associated with central sensitization. The scale is scored from 0 to 100, with higher scores indicating higher levels of central sensitization.
Time frame: 1 month
Change in Subjective Sleep Quality as Measured by the Pittsburgh Sleep Quality Index (PSQI) score
The change in subjective sleep quality will be assessed by the Pittsburgh Sleep Quality Index (PSQI) score. The PSQI is a self-rated questionnaire that assesses sleep quality over the last month. The scale includes seven component scores, and a global score is derived, ranging from 0 to 21. Higher scores indicate poorer sleep quality.
Time frame: 1 month
Change in Absolute Alpha Band Power (8-12 Hz) at Electrode Site [F3/F4/C3/C4/P3/P4] as Assessed by Electroencephalogram (EEG).
Absolute alpha band power will be calculated from resting EEG recordings and expressed in µV²/Hz. Recordings will be acquired from the \[specific electrode site\] electrode.
Time frame: 1 month
Change in Heart Rate Variability (HRV) as Assessed by the Standard Deviation of NN Intervals (SDNN)
SDNN will be collected from 3-minute resting recordings and expressed in milliseconds (ms). This specifies the exact HRV metric (SDNN) and its unit, making it clear and quantifiable
Time frame: 1 month
Change in Interhemispheric Absolute Alpha Band Power Asymmetry (8-12 Hz) Between [F3 and F4 / C3 and C4 / P3 and P4] as Assessed by Electroencephalogram (EEG)
Interhemispheric absolute alpha band power asymmetry will be calculated from resting EEG recordings and expressed as a ratio. Recordings will be acquired from \[F3 and F4 / C3 and C4 / P3 and P4\] electrode pairs.
Time frame: 1 month
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