Transcranial Direct Current Stimulation (tDCS) in Different Psychiatric Disorders
Phase: NA
Conditions: Major Depressive Disorder (MDD), SCHIZOPHRENIA 1 (Disorder), Obsessive-Compulsive Disorder, Generalized Anxiety Disorder, Insomnia
Sponsor: Menoufia University

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
 
Official title of the study : Transcranial Direct Current 
Stimulation (tDCS) in Different psychiatric disorders 
 
NCT number: Pending  
Date of the document: 1/12/2023 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
Introduction  
Transcranial Direct Current Stimulation (tDCS) is a non-invasive 
neuromodulation technique that delivers low-intensity direct current 
(typically 1–2 mA) through scalp electrodes (Nitsche MA, Paulus W., 
2011)..  
Although it does not induce action potentials directly, it modulates 
cortical excitability and induces plastic changes that can outlast the 
stimulation period . 
Understanding the mechanisms of tDCS is essential to explain its 
therapeutic potential in various psychiatric disorders . 
 The dorsolateral prefrontal cortex (DLPFC) is the most frequently 
targeted region in psychiatric research  (  Lefaucheur J-P et al., 2020 ) 
Advantages 
- Non-invasive and safe compared to electroconvulsive therapy (ECT) 
or deep brain stimulation (DBS) (Fregni F. et al., 2021.)..   
 - Portable and relatively inexpensive equipment. - Can be combined 
with pharmacological or psychotherapeutic interventions . 
- Potential for repeated sessions and home-based supervised (Bikson 
M. et al., 2019). 
Applications . 
- Flexible targeting of cortical regions based on symptoms 
(depression, hallucinations, compulsions) 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
Safety 
 Reviews of thousands of sessions confirm safety when 
following standard parameters (1–2 mA) , 
 
20
–
30
 
minutes, ≤40 sessions 
 No evidence of structural brain damage ( Kekic M. et al., 2016 )  
Common transient effects : 
Tingling, itching, headache, skin redness.  
Caution is advised in patients with implanted medical devices, 
uncontrolled seizures, or unstable neurological conditions 
Mechanism of Action of Transcranial Direct Current Stimulation 
(tDCS) in Psychiatric Disorders . 
1. Subthreshold Membrane Polarization 
Anodal stimulation slightly depolarizes neuronal membranes, while 
cathodal stimulation tends to hyperpolarize them.  
This does not trigger action potentials but biases neurons toward or 
away from firing, thereby modulating cortical excitability (Qi S  . 2024) 
 
 
2. Cortical Excitability and Neurotransmitter Balance 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
tDCS alters cortical excitability by modulating inhibitory and 
excitatory neurotransmitters (e.g., reducing GABA and modulating 
glutamate levels). 
These shifts contribute to short-term changes in mood, cognition, and 
behavior (Medeiros L.F. 2012 ) . 
3.Synaptic Plasticity (LTP/LTD-like mechanisms(  
Repeated stimulation facilitates long-term potentiation (LTP) or long-
term depression (LTD)-like effects through NMDA receptor and calcium 
channel involvement . 
This underlies sustained after-effects of tDCS beyond the stimulation 
session.( Wang S. 2024 ). 
 4.Neurotrophic Factors and Gene Expression 
tDCS enhances BDNF signaling and related molecular pathways, 
promoting synaptic plasticity and structural remodeling . 
This may explain long-lasting therapeutic effects in mood and 
cognitive disorders.( Yamada Y.2021). 
 5.Network-Level Modulation 
tDCS influences large-scale brain networks, including the default 
mode network (DMN), frontoparietal network, and limbic circuits . 
This network reorganization is crucial for psychiatric applications, 
particularly in depression, anxiety, and psychosis  (Woods A.J. A
 ) 
2016
  .
 
6.Glial and Neurovascular Effects 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
Evidence suggests modulation of astrocytic activity, neuro-
inflammation, and local cerebral blood flow (CBF) 
These may indirectly contribute to clinical benefit ( Liu A. et al. 
2018). 
 7.Neuromodulator Systems 
tDCS impacts dopaminergic, serotonergic, and cholinergic pathways, 
which are central to psychiatric disorders such as depression, schizophrenia, 
and addiction (Liu A. et al. 2018 ) . 
 Clincal uses of tDCS in psychiatry : 
Depression (MDD): Anodal stimulation of the left dorsolateral 
prefrontal cortex (DLPFC) reduces mood symptoms via plasticity, BDNF 
enhancement, and network rebalancing.( Loo et al., 2018) 
Schizophrenia: Targeting prefrontal and temporoparietal regions 
reduces 
auditory 
hallucinations 
and 
improves 
cognition 
through 
connectivity modulation. (Koops et al., 2018). 
Anxiety, OCD, PTSD: Modulation of prefrontal–limbic interactions 
helps regulate hyperactive threat responses and improves executive control . 
(Nitsche MA, Paulus W., 2011).( Mondino M. et al., 2015.) 
Insomnia: tDCS shows promise for improving insomnia symptoms 
and sleep quality, but results are mixed and effect sizes vary across 
studies.(Fregni F. et al., 2021). 
Aim of the Work 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
Primary aim: 
 To evaluate the efficacy and safety of transcranial direct 
current stimulation (tDCS) in reducing core symptoms of 
different psychiatric disorders using validated clinical scales. 
Secondary aims: 
 To assess response and remission rates. 
 To evaluate the durability of treatment effects over follow-up. 
 To examine effects on cognition, daily functioning, and quality 
of life. 
 To monitor tolerability and adverse events. 
 
 
 
 
 
 
 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
Methodology 
Ethical Considerations
  
Approval from the local research and ethical committee, 
Menoufia University, Egypt, ( 2025) for the study 
• 
Informed Consent : 
Written informed consent was obtained from all 
participants or guardians 
Participants must receive full information about the 
purpose, procedures, potential benefits, and risks of tDCS, with 
the opportunity to withdraw at any time without penalty. 
• 
Confidentiality : 
  
Participant data must be anonymized and securely stored 
to ensure privacy . 
     1 - Study Design 
A comparative cross-sectional study including five 
diagnostic groups : 
 Major Depressive Disorder (MDD), Schizophrenia, 
Obsessive–Compulsive Disorder (OCD), Generalized Anxiety 
Disorder (GAD), and Insomnia . Diagnostic assessments 
followed DSM-5 criteria using structured clinical interviews. 
 
 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
Participants 
A total of 325 patients were recruited (65 per group) from 
psychiatric outpatient clinics between (Month January 2024– to 
June 2025) 
Inclusion Criteria : 
 Adults aged 16–65 years, meeting DSM-5 diagnosis, and 
providing 
informed 
consent 
(American 
Psychiatric 
Association) 
 Diagnosis confirmed via DSM-5  criteria. 
 Stable medication regimen (if applicable) for ≥4 weeks. 
 No history of seizures or intracranial metal implants . 
Exclusion Criteria : 
 Severe neurological conditions (e.g., epilepsy, brain tumors .) 
 Pregnancy  
 active substance abuse 
 severe cognitive impairment, or comorbid psychiatric disorders 
interfering with assessment. 
Sample Size Justification 
A sample of 65 subjects per group provides approximately 80% 
statistical power to detect medium effect sizes (Cohen’s d ≈ 
0.5) at α = 0.05, according to power calculation guidelines 
(Serdar CC et al). 
 
 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
 2. tDCS Parameters 
 Disorder Target Region  
 Electrode Montage 
 Current Intensity  
 Duration Sessions  
Depression : 
 Montgomery–Åsberg  Depression Rating Scale (MADRS) 
(Montgomery SA & Åsberg M )
 .  
 Left DLPFC (F3) Anode: F3, Cathode: right supraorbital 
 
2  mA 
20
 -
30
 
min  
 
10
  -
20
 
 daily  (Brunoni et al. 2016 ) 
Schizophrenia 
 
 Positive and Negative Syndrome Scale (PANSS)  (Kay SR et 
al.). 
 Left TPJ (P3) + Left DLPFC (F3) 
 Anode: P3, Cathode: F3 (for hallucinations) 
  2 mA 20 min 
 10-15 (Brunelin et al. 2012). 
OCD  
 Yale–Brown Obsessive Compulsive Scale (Y-BOCS)  
(Goodman WK et al). 
 SMA (Cz) or OFC (Fp1/Fp2) 
 Anode: Cz/Fp1, Cathode: contralateral shoulder 
  2 mA 20
 
min 
 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
 
10
 -
20
 
 ( Dinn et al. 2019). 
Anxiety (GAD/PTSD) 
 
 Generalized Anxiety Disorder-7 (GAD-7). 
 Right DLPFC (F4) or vmPFC 
 
 Anode: F4, Cathode: left DLPFC (F3) 
 2 mA -Session duration: 20–30 minutes per session . 
 10 
 (Shiozawa et al. 2014). 
     Insomnia 
 Insomnia Severity Index (ISI) — 7 items, sensitive to change; 
commonly used as primary outcome in tDCS insomnia trials.  
 Left DLPFC (F3) or Parietal (Pz) 
 Anode: F3/Pz, Cathode: contralateral supraorbital  
 2 mA -Session duration: 20–30 minutes per session. 
 10 -12  (Frase et al. 2019) 
3-  Procedure 
Preparation : 
 Clean scalp with alcohol to reduce impedance . 
 Apply conductive gel and position electrodes using the 10-20 
EEG system . 
 Use rubber electrodes (5×7 cm) for anodal/cathodal placement . 
Stimulation : 
Ramp-up current over 30 sec to avoid discomfort . 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
Monitor for adverse effects (tingling, itching, headache ). 
Post-Stimulation Assessment : 
 Evaluate symptom changes using standardized scales (e.g., 
HAM-D for depression, Y-BOCS for OCD) . 
 Repeat sessions 3-5 times per week.. 
4. Safety and Monitoring 
 Adverse Effects: 
 Mild skin irritation, headache  
(rarely seizures—screen high-risk patients .) 
 Contraindications : 
Metallic implants, scalp lesions, epilepsy history . 
 Conclusion 
tDCS is a promising neuromodulatory tool for psychiatric disorders, 
with varying protocols based on disorder-specific neural targets. 
Statistical Analysis
  
Data were analyzed using SPSS. Descriptive statistics were presented 
as mean ± SD and frequencies . 
Between-group comparisons used ANOVA for continuous variables 
and Chi-square tests for categorical variables . 
Significance was set at p < 0.05 with 95% confidence intervals. 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
Results and Discussion
  
The data obtained from this study will be tabulated, 
discussed and compared with other researches and published data 
when available. 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 

Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
References
 
 
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Mental Disorders, 5th Ed. (DSM
      
  
Bikson M. et al., 2019. Safety of transcranial direct current stimulation. 
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Fregni F. et al., 2021. Neuromodulation in psychiatry: tDCS update. The 
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Goodman WK et al. Y-BOCS development. 
 
Kay SR et al. PANSS for Schizophrenia
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Transcranial Direct Current Stimulation (tDCS) in Different psychiatric disorders
  
 
NCT number: Pending         Date of the document: 1/12/2023 
 
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