The Effects of HD-tDCS on Cognitive Bias Among Individuals With Social Anxiety Symptoms
CompletedNAResults postedLast updated 10 December 2025
What this trial tests
NA trial testing Active High-definition transcranial direct current stimulation in Social Anxiety Disorder in 74 participants. Completed in 24 December 2024.
Timeline
15 May 2024
Primary endpoint 24 November 2024
24 December 2024
Quick facts
Lead sponsor
South China Normal University
Phase
NA
Status
Completed
Study type
INTERVENTIONAL
Allocation
randomized
Design
parallel
Masking
single
Primary purpose
treatment
Enrollment
74
Start date
15 May 2024
Primary completion
24 November 2024
Estimated completion
24 December 2024
Sites
1 location across China
Drugs / interventions tested
Active High-definition transcranial direct current stimulation
Sham high-definition transcranial direct current stimulation
Adults 18 to 24, any sex, with Social Anxiety Disorder. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Trial-level Bias Score (Negative)Primary· This task was administered at baseline (Day 1) and immediately after the last stimulation session (Day 5).
Assessment: Dot probe task;Indicator of Attention Avoidance. Dot probe task is a common experimental paradigm for measuring attention bias. After appearance of a fixed cross in the center of the computer screen, a pair of faces appear side by side. Then, a probe appears on the location previously occupied by one of the two faces. Participants were asked to response the location of the probe as quickly as possible and press the appropriate keys to answer.
This study used the trail-level bias score (TL-BS) as a measure of the main outcomes of this task. TL-BS is an indicator of reaction time (R
Pre-test
Group
Value
95% CI
tDCS group
-54.92
± 22.28
Sham group
-48.45
± 17.96
Post-test
Group
Value
95% CI
tDCS group
-44.29
± 16.79
Sham group
-46.07
± 18.71
Endorsement Rates of Negative InterpretationsPrimary· This task was administered at baseline (Day 1) and immediately after the last stimulation session (Day 5)
Assessment: Word-sentence association paradigm; Indicator of Negative interpretation bias.
Word sentence association paradigm (WSAP) was used to assess the interpretation bias in youth with social anxiety. Following the appearance of a fixed cross (500ms), an ambiguous sentence describing the social situation would be presented in the center of the screen (2000ms). Then, a word would appear at random for 500ms: the word might imply a threatening interpretation (e.g., "boring" or "rejection"), or imply a benign one (e.g., "captivating" or "accepted"). Participants were asked to decide whether
Pre-test
Group
Value
95% CI
tDCS group
0.48
± 0.19
Sham group
0.44
± 0.18
Post-test
Group
Value
95% CI
tDCS group
0.41
± 0.21
Sham group
0.44
± 0.22
Peak Trial-level Bias Score (Negative)Secondary· This task was administered at baseline (Day 1) and immediately after the last stimulation session (Day 5)
Assessments: Dot-probe task; Indicator of Attention Avoidance. Dot probe task is a common experimental paradigm for measuring attention bias. After appearance of a fixed cross in the center of the computer screen, a pair of faces appear side by side. Then, a probe appears on the location previously occupied by one of the two faces. Participants were asked to response the location of the probe as quickly as possible and press the appropriate keys to answer.
This study used the trail-level bias score (TL-BS) as a measure of the main outcomes of this task. TL-BS is an indicator of reaction time
Pre-test
Group
Value
95% CI
tDCS group
-189.32
± 79.33
Sham group
-159.66
± 86.08
Post-test
Group
Value
95% CI
tDCS group
-133.09
± 66.52
Sham group
-139.22
± 62.64
Bias ScoreSecondary· This task was administered at baseline (Day 1) and immediately after the last stimulation session (Day 5)
Assessments: Word-sentence association paradigm; Indicator of Negative interpretation bias.
Word sentence association paradigm (WSAP) was used to assess the interpretation bias in youth with social anxiety. Following the appearance of a fixed cross (500ms), an ambiguous sentence describing the social situation would be presented in the center of the screen (2000ms). Then, a word would appear at random for 500ms: the word might imply a threatening interpretation (e.g., "boring" or "rejection"), or imply a benign one (e.g., "captivating" or "accepted"). Participants were asked to decide whether
Pre-test
Group
Value
95% CI
tDCS group
-39.85
± 383.45
Sham group
-92.98
± 459.47
Post-test
Group
Value
95% CI
tDCS group
-80.72
± 363.52
Sham group
45.72
± 307.73
Recall Accuracy for Negative WordsSecondary· This task was administered at baseline (Day 1) and immediately after the last stimulation session (Day 5)
Assessments: free recall task; Indicator of negative memory bias. This study used free recall and recognition task to assess memory bias by the number of positive/negative words remembered. First, in the "encoding phase", after a short time for a fixed cross, words were presented randomly in turn . Participants were asked to read these words aloud and answer coding questions.After this phase, there was a 3-minute distraction task, during which participants were guided through 40 calculation problems. They were then given 2 minutes to freely recall the words that had appeared before, regardless
Pre-test
Group
Value
95% CI
tDCS group
0.15
± 0.09
Sham group
0.15
± 0.08
Post-test
Group
Value
95% CI
tDCS group
0.13
± 0.08
Sham group
0.15
± 0.09
Social Anxiety SymptomsSecondary· Self-report questionnaires were administered at baseline (Day 1), immediately after the last stimulation session (Day 5), and at a 4-week follow-up (Day 30).
Assessments: the Liebowitz Social Anxiety Scale. The Liebowitz Social Anxiety Scale (LSAS) was used to identify participants with social anxiety and to assess changes in social anxiety symptoms before and after the tDCS intervention. The scale contains 24 items, each of which assesses two aspects of fear and avoidance, using a 4-point Likert scale ("0" means "never" and "3" means "severe"), for a total of 48 items. A higher score indicated more severe social anxiety. The score ranges from 0 to 144. The total score would be categorized into 5 severity levels: 0-54 (normal), 55-64 (moderate), 65
Pre-test
Group
Value
95% CI
tDCS group
72.7
± 16.8
Sham group
66.94
± 12.72
Post-test
Group
Value
95% CI
tDCS group
63.39
± 13.77
Sham group
63.52
± 13.89
Follow-up
Group
Value
95% CI
tDCS group
61.79
± 12.09
Sham group
60.42
± 13.75
Trait AnxietySecondary· Self-report questionnaires were administered at baseline (Day 1), immediately after the last stimulation session (Day 5), and at a 4-week follow-up (Day 30).
Assessments: the Spielberger Inventory - Trait (STAI-T). Trait anxiety was assessed using the Spielberger Trait Anxiety Inventory - Trait (STAI-T), which included 20 items rated on a 4-point scale, ranging from 20 to 80 (1 = "not at all" to 4 = "very much"). A higher score indicates severe trait anxiety symptoms. In this study, the STAI-T demonstrated good internal and test-retest reliability (Cronbach's alpha = 0.80-0.86; r = 0.69-0.79, p \< 0.001).
Pre-test
Group
Value
95% CI
tDCS group
39.74
± 7.42
Sham group
42.87
± 5.95
Post-test
Group
Value
95% CI
tDCS group
36.55
± 6.25
Sham group
41.45
± 7.40
Follow-up
Group
Value
95% CI
tDCS group
37.97
± 7.65
Sham group
42.03
± 7.73
Negative Cognitive Bias (Attention Bias)Secondary· Self-report questionnaires were administered at baseline (Day 1), immediately after the last stimulation session (Day 5), and at a 4-week follow-up (Day 30).
Assessments: the Negative cognitive processing bias questionnaire; Indicator of self-report attention bias.
Participants completed the Negative cognitive processing bias questionnaire (NCPBQ). The NCPBQ included 17 items divided into three subscales, along with three lie-detection items. Among it, the attention bias subscale includes 5 items (E.g., My attention is easily drawn to the tragic images on TV and is difficult to shift). Items were rated on a 5-point Likert scale from 1 ("disagree completely") to 5 ("agree completely"), with higher score indicating more severe cognitive bias. The sc
Pre-test
Group
Value
95% CI
tDCS group
16.64
± 4
Sham group
15.81
± 3.42
Post-test
Group
Value
95% CI
tDCS group
16.64
± 4.20
Sham group
15.58
± 4.36
Follow-up
Group
Value
95% CI
tDCS group
16.12
± 4.42
Sham group
15.81
± 4.48
Recognition Accuracy for Negative WordsPrimary· This task was administered at baseline (Day 1) and immediately after the last stimulation session (Day 5)
Assessments: recognition task; Indicator of Negative Memory bias. This study used free recall and recognition task to assess memory bias by the number of positive/negative words remembered. First, in the "encoding phase", after a short time for a fixed cross, words were presented randomly in turn . Participants were asked to read these words aloud and answer coding questions.After this phase, there was a 3-minute distraction task, during which participants were guided through 40 calculation problems. They were then given 2 minutes to freely recall the words that had appeared before, regardless
Pre-test
Group
Value
95% CI
tDCS group
0.84
± 0.11
Sham group
0.82
± 0.13
Post-test
Group
Value
95% CI
tDCS group
0.77
± 0.12
Sham group
0.82
± 0.16
Negative Cognitive Bias (Interpretation Bias)Secondary· Self-report questionnaires were administered at baseline (Day 1), immediately after the last stimulation session (Day 5), and at a 4-week follow-up (Day 30).
Assessments: the Negative cognitive processing bias questionnaire; Indicator of self-report interpretation bias.
Participants completed the Negative cognitive processing bias questionnaire (NCPBQ). The NCPBQ included 17 items divided into three subscales, along with three lie-detection items. Among it, the interpretation bias subscale includes 5 items (E.g., If a new teacher is hard on me, I think it is because he sees me in a bad light and wants to get me in trouble). Items were rated on a 5-point Likert scale from 1 ("disagree completely") to 5 ("agree completely"), with higher score indica
Pre-test
Group
Value
95% CI
tDCS group
15.39
± 2.99
Sham group
16.74
± 3.43
Post-test
Group
Value
95% CI
tDCS group
15.36
± 3.81
Sham group
15.94
± 4.40
Follow-up
Group
Value
95% CI
tDCS group
14.39
± 3.97
Sham group
15.81
± 4.49
Negative Cognitive Bias (Memory Bias)Secondary· Self-report questionnaires were administered at baseline (Day 1), immediately after the last stimulation session (Day 5), and at a 4-week follow-up (Day 30).
Assessments: the Negative cognitive processing bias questionnaire; Indicator of self-report memory bias.
Participants completed the Negative cognitive processing bias questionnaire (NCPBQ). The NCPBQ included 17 items divided into three subscales, along with three lie-detection items. Among it, the memory bias subscale includes 4 items (E.g., I can easily remember the negative comments people make about me). Items were rated on a 5-point Likert scale from 1 ("disagree completely") to 5 ("agree completely"), with higher score indicating more severe cognitive bias . The score of memory bias sub
Pre-test
Group
Value
95% CI
tDCS group
16.06
± 2.32
Sham group
14.55
± 2.22
Post-test
Group
Value
95% CI
tDCS group
16.09
± 2.57
Sham group
14.77
± 2.79
Follow-up
Group
Value
95% CI
tDCS group
14.85
± 3.38
Sham group
14.52
± 2.84
Adverse events — posted to ClinicalTrials.gov
Time frame: After each stimulation session, participants completed an adverse event checklist to monitor tolerability and perceived stimulation. In other words, every participant underwent adverse event assessments from the first to the last intervention, for up to five consecutive days..
Reporting threshold: 0%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by South China Normal University
Last refreshed: 10 December 2025
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