Transcranial Alternating Current Stimulation for Generalized Anxiety Disorder and Insomnia: An Open-Label Pilot Study (NewWaves)

February 19, 2026 updated by: Andre R Brunoni, University of Sao Paulo

Transcranial Alternating Current Stimulation for the Treatment of Anxiety and Insomnia: An Open-Label Pilot Clinical Trial

This is an open-label pilot clinical trial to evaluate the effects of transcranial alternating current stimulation (tACS) in adults diagnosed with generalized anxiety disorder (GAD) and chronic primary insomnia. The study will involve 30 participants who will receive 20 sessions of tACS over four weeks. The stimulation will be delivered at 15 mA and 77.5 Hz using the Nexalin device. The main goal is to assess improvements in anxiety and sleep quality. Results from this study will provide preliminary evidence for future randomized controlled trials.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Generalized Anxiety Disorder (GAD) and chronic primary insomnia are highly prevalent and frequently co-occurring psychiatric conditions associated with significant functional impairment and reduced quality of life. Both disorders are characterized by dysregulation of cortical and subcortical neural circuits involved in emotional regulation and sleep-wake control, including abnormal oscillatory activity in fronto-limbic networks. Although pharmacological and psychotherapeutic interventions are considered first-line treatments, a substantial proportion of patients remain symptomatic or experience adverse effects, highlighting the need for novel neuromodulatory strategies.

Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that delivers low-intensity sinusoidal electrical currents at specific frequencies to entrain endogenous neural oscillations. By modulating frequency-specific cortical rhythms, tACS may influence neural synchrony and connectivity patterns implicated in anxiety and sleep disturbances.

The present study is an open-label, single-arm pilot clinical trial designed to investigate the feasibility, safety, tolerability, and preliminary clinical effects of tACS in adults with GAD and chronic insomnia. Participants will undergo 20 stimulation sessions administered over four consecutive weeks (five sessions per week). Stimulation will be delivered using the Nexalin device at a frequency of 77.5 Hz and an intensity of 15 mA. Electrodes will be positioned over the frontal pole (Fpz) and bilateral mastoid regions according to the international 10-20 EEG system.

Clinical assessments will be conducted at baseline, at the end of the 4-week treatment phase, and at a 4-week post-treatment follow-up visit. The study will examine changes in anxiety severity, sleep quality, mood symptoms, global clinical status, and cognitive/functional performance to characterize the potential therapeutic effects of this intervention.

The trial will be conducted at the Interdisciplinary Neuromodulation Service of the Institute of Psychiatry, Hospital das Clínicas, University of São Paulo Medical School (IPq-HCFMUSP). Findings from this pilot study are intended to inform the design of future randomized, sham-controlled clinical trials and contribute to the expanding investigation of transcranial alternating current stimulation as a potential treatment modality in anxiety and sleep disorders.

Study Type

Interventional

Enrollment (Estimated)

30

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Brazil
    • São Paulo
      • São Paulo, São Paulo, Brazil, 05403-010

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age between 18 and 65 years;
  • Diagnosis of Generalized Anxiety Disorder (GAD) based on Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria;
  • Diagnosis of chronic primary insomnia;
  • Minimum score of 17 on the Hamilton Anxiety Rating Scale (HAM-A), indicating at least mild to moderate anxiety symptoms;
  • Score >7 on the Pittsburgh Sleep Quality Index (PSQI);
  • Stable use of antidepressants (SSRI or SNRI) is allowed;
  • Limited use of benzodiazepines (maximum of 10 mg/day diazepam equivalent).

Exclusion Criteria:

  • History of mania, hypomania, or bipolar disorder;
  • Contraindications to the use of transcranial stimulation;
  • Active suicidal ideation or suicide attempt in the last 4 weeks;
  • Refractoriness to 3 or more antidepressant treatments;
  • Pregnancy;
  • Other psychiatric diagnoses (e.g., schizophrenia, substance dependence, major depressive disorder);
  • Severe medical or neurological conditions;
  • Anxiety or insomnia secondary to other medical or psychiatric conditions (e.g., hypothyroidism, anemia).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: tACS Group
Participants will receive 20 sessions of transcranial alternating current stimulation (tACS) over four weeks (five sessions per week). The stimulation will be delivered at 15 mA and 77.5 Hz using the Nexalin device, with electrodes placed at Fpz and mastoid areas.
Device: Transcranial Alternating Current Stimulation (tACS)
20 sessions of 40 minutes each, applied five times per week over four weeks, with a current of 15 mA at 77.5 Hz using the Nexalin device.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Anxiety Severity Measured by the Hamilton Anxiety Rating Scale (HAM-A)
Time Frame: Baseline, Week 4, Week 8
The Hamilton Anxiety Rating Scale (HAM-A) is a clinician-administered scale ranging from 0 to 56, with higher scores indicating greater anxiety severity. The outcome measure is the change in total HAM-A score from baseline to Week 4 and Week 8.
Baseline, Week 4, Week 8
Change in Sleep Quality (Pittsburgh Sleep Quality Index - PSQI)
Time Frame: Baseline, Week 4, Week 8
The Pittsburgh Sleep Quality Index (PSQI) is a self-reported questionnaire ranging from 0 to 21, with higher scores indicating worse sleep quality. The outcome measure is the change in total PSQI score from baseline to Week 4 and Week 8.
Baseline, Week 4, Week 8

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Depressive Symptoms Measured by the Hamilton Depression Rating Scale (HAM-D)
Time Frame: Baseline, Week 4, Week 8
The Hamilton Depression Rating Scale (HAM-D) ranges from 0 to 52, with higher scores indicating greater depressive symptom severity. The outcome measure is the change in total HAM-D score from baseline to Week 4 and Week 8.
Baseline, Week 4, Week 8
Change in Global Clinical Status Measured by the Clinical Global Impression (CGI) Scale
Time Frame: Baseline, Week 4, Week 8
The Clinical Global Impression (CGI) scale includes severity and improvement subscales. The CGI-Severity scale ranges from 1 to 7, with higher scores indicating greater illness severity. The outcome measure includes changes from baseline to Week 4 and Week 8.
Baseline, Week 4, Week 8
Change in Quality of Life Measured by the WHOQOL-BREF
Time Frame: Baseline, Week 4, Week 8
The World Health Organization Quality of Life - Brief Version (WHOQOL-BREF) is a self-reported questionnaire assessing quality of life across physical, psychological, social, and environmental domains. Scores range from 0 to 100, with higher scores indicating better quality of life. The outcome measure is the change in total score from baseline to Week 4 and Week 8.
Baseline, Week 4, Week 8
Incidence of Treatment-Emergent Adverse Events
Time Frame: Throughout the 8-week study period
Number and nature of adverse events, including local discomfort, headache, skin irritation, or fatigue.
Throughout the 8-week study period

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Sao Paulo

Investigators

  • Study Chair: Valquíria A Silva, MD, PhD, University of Sao Paulo

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 1, 2025

Primary Completion (Actual)

January 31, 2026

Study Completion (Estimated)

May 31, 2026

Study Registration Dates

First Submitted

April 22, 2025

First Submitted That Met QC Criteria

February 19, 2026

First Posted (Actual)

February 24, 2026

Study Record Updates

Last Update Posted (Actual)

February 24, 2026

Last Update Submitted That Met QC Criteria

February 19, 2026

Last Verified

April 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 85503824.0.0000.0068
  • ID Number: 85503824.0.0000.006 (Other Identifier: Brazilian National Research Ethics Committee (CEP))

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Individual participant data (IPD) that underlie the results reported in this article will be made available after deidentification, including study protocol and statistical analysis plan.

IPD Sharing Time Frame

Beginning 6 months following publication, for up to 2 years.

IPD Sharing Access Criteria

Qualified researchers whose proposals are approved by the principal investigator will be granted access to deidentified individual participant data. Requests must include a clear scientific rationale and plan for data use. Data will be shared through secure electronic transfer upon agreement with data use terms.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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