Repetitive Transcranial Magnetic Stimulation for People With Etomidate Addiction (SToP-E-rTMS x Etomidate) (SToP-E)

Substance Misuse To Psychiatric Disorders for Etomidate -Repetitive Transcranial Magnetic Stimulation for People With Etomidate Addiction: a 6-month, Double-blind, Randomized, Sham-controlled Trial

The goal of this clinical trial is to learn if high-frequency rTMS works to treat etomidate addiction in adults. It will also learn about the safety and tolerability of rTMS. The main questions it aims to answer are:

• Does active rTMS reduce craving, amount of etomidate use, frequency of etomidate use, and severity of etomidate use disorder?
• Does active rTMS improve cognitive biases related to delayed reward discounting and risk sensitivity?
• What side-effects do participants have when receiving rTMS?

Researchers will compare active rTMS to sham rTMS to see if active rTMS works to treat etomidate addiction.

Participants will:

• Receive active rTMS or sham rTMS over 4 weeks
• Complete 20 rTMS sessions in total
• Visit the clinic for treatment sessions and follow-up assessments
• Complete assessments of etomidate use, craving, withdrawal symptoms, mood symptoms, cognition, and decision-making

Attend follow-up assessments up to 6 months after baseline

Study Overview

• Status: Not yet recruiting
• Conditions: Repetitive Transcranial Magnetic Stimulation (rTMS); Etomidate Use Disorder
• Intervention / Treatment: Device: high-frequency Repetitive Transcranial Magnetic Stimulation; Device: Repetitive transcranial magnetic stimulation

Detailed Description

This is a 6-month, double-blind, randomized, sham-controlled pilot clinical trial evaluating high-frequency repetitive transcranial magnetic stimulation (rTMS) for people with etomidate addiction. Etomidate misuse has become an emerging public health concern, but there is currently no established treatment specifically for etomidate addiction. This study will examine whether active rTMS delivered to the left dorsolateral prefrontal cortex can reduce etomidate craving, use, and dependence severity compared with sham rTMS.

The study will enroll 40 participants with etomidate use disorder. Participants will be randomly assigned in a 1:1 ratio to receive either active rTMS or sham rTMS. Both participants and outcome assessors will be blinded to treatment allocation. The intervention consists of 20 rTMS sessions delivered over 4 weeks, followed by an observation maintenance phase with follow-up assessments up to 6 months from baseline.

The study will assess changes in etomidate use, craving, withdrawal symptoms, dependence severity, anxiety, depression, global cognition, psychomotor speed, and cognitive biases related to delayed reward discounting and risk sensitivity. These assessments will help determine whether rTMS may be a feasible and potentially effective intervention for etomidate addiction and related decision-making processes.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Albert KK Chung; Phone Number: +85260440993; Email: Chungkka@hku.hk

Study Locations

• Hong Kong
  • Hong Kong
    • Hong Kong, Hong Kong, Hong Kong, 000000
      • Queen Mary Hospital
      • Contact: Ablert KK Chung; Email: chungkka@hku.hk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Able to read and communicate in English and/or Chinese
• Able to give informed consent and/or able to provide an informed consent from the legal guardian (if applicable)
• Using etomidate and/or its related analogues as the primary psychoactive substance of abuse

• Suffering from etomidate addiction as defined by:

  1. Etomidate Use Disorder classified under "Sedative-, Hypnotic-, or Anxiolytic Use Disorder" according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) with severity ≥ 1, or
  2. Harmful Use or Dependence for etomidate classified under "Mental and behavioral disorders due to use of sedatives or hypnotics" according to the International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10), or
  3. Hazardous use, harmful use or dependence classified under "Hazardous use of sedatives, hypnotics or anxiolytics" or "Disorders due to use of sedatives, hypnotics or anxiolytics" according to the Clinical descriptions and diagnostic requirements for International Classification of Diseases 11th Revision (ICD-11) mental, behavioral, and neurodevelopmental disorders.

Exclusion Criteria:

• Age < 18 years old
• Unable to read English or Chinese
• Unable to give informed consent

• Had been diagnosed with the following disorders including:

  1. Neurodevelopmental Disorders:

• DSM-5: Intellectual Disabilities, Communication Disorders, Specific Learning Disorder, Autism Spectrum Disorder and Motor Disorders
• International Statistical Classification of Diseases and Related Health Problems 11th Revision (ICD-11): Disorders of intellectual development (6A00), Developmental speech or language disorders (6A01), Autism spectrum disorder (6A02), Developmental learning disorder (6A03), Developmental motor coordination disorder (6A04), Stereotyped movement disorder (6A06), Primary tics or tic disorders (8A05.0)
• Other DSM-5 defined Substance Use Disorder greater than moderate in severity (i.e., severity score ≥4)
• Neurocognitive Disorders (DSM-5, or ICD-11 6D70-72 & 6D80-86) 2. Contra-indicated to undergo rTMS:
• with electronic and/or magnetic implants (e.g., pacemaker, implantable cardioverter defibrillator [ICD], cerebral shunts, cochlear implant, etc.)
• with metallic or mechanic fragments (e.g., screws, plates, stents, clips, etc.)
• pregnant
• with any known or history of neurological conditions including cerebral vascular accidents (CVA), epilepsy, brain tumor or space occupying lesion, etc.
• poorly controlled or unstable diabetes mellitus
• receiving unstable dose(s) of antipsychotics, antidepressants, benzodiazepines and/or anticonvulsants in the past 3 months

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Active rTMS; Subjects receive 20 high-frequency rTMS sessions over 4 weeks.	Device: high-frequency Repetitive Transcranial Magnetic Stimulation; high-frequency rTMS using Magventure TMS system using the Coil Cool-B70 Active/Placebo Bended Butterfly coil is delivered at the dorsolateral prefrontal cortex of consented subjects
Sham Comparator: Sham rTMS; Subjects receive 20 Sham rTMS sessions over 4 weeks.	Device: Repetitive transcranial magnetic stimulation; Sham rTMS will be delivered using the Coil Cool-B70 Active/Placebo Bended Butterfly coil, which generates a negligible magnetic field. The sham procedure will follow the same schedule as the active rTMS arm.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in etomidate craving	Change in craving measured by the Craving Automated Scale-Substance from baseline to follow-up. Higher scores indicate stronger craving.	Baseline, Week 1, Week 4, Month 3, and Month 6
Change in etomidate withdrawal symptoms	Change in withdrawal symptoms measured by the Clinical Institute Withdrawal Assessment for Benzodiazepines from baseline to follow-up.	Baseline, Week 1, Week 4, Month 3, and Month 6
Change in amount of etomidate use	Change in the amount of etomidate use over the past 30 days measured by the Beat Drugs Fund Evaluation Question Set No. 5 and substance use interview from baseline to follow-up.	Baseline, Week 1, Week 4, Month 3, and Month 6
Change in frequency of etomidate use	Change in the frequency of etomidate use over the past 30 days measured by the Beat Drugs Fund Evaluation Question Set No. 5 and substance use interview from baseline to follow-up.	Baseline, Week 1, Week 4, Month 3, and Month 6
Change in severity of dependence	Change in severity of dependence measured by the Severity of Dependence Scale from baseline to follow-up. Higher scores indicate greater dependence severity.	Baseline, Week 1, Week 4, Month 3, and Month 6
Change in urine-confirmed etomidate use	Change in etomidate use status assessed by urine test from baseline to follow-up. Urine testing will be used to assess recent etomidate use and compare biological testing results with self-reported etomidate use.	Baseline, Week 1, Week 4, Month 3, and Month 6

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in anxiety symptoms	Change in anxiety symptoms measured by the Beck Anxiety Inventory from baseline to follow-up. Higher scores indicate more severe anxiety symptoms.	Baseline, Week 1, Week 4, Month 3, and Month 6
Change in depressive symptoms	Change in depressive symptoms measured by the Beck Depression Inventory-II from baseline to follow-up. Higher scores indicate more severe depressive symptoms.	Baseline, Week 1, Week 4, Month 3, and Month 6
Change in delayed reward discounting	Change in delayed reward discounting measured by a delay discounting task from baseline to follow-up. The task assesses preference for smaller immediate rewards versus larger delayed rewards.	Baseline, Week 4, Month 3, and Month 6
Change in risk sensitivity	Change in risk sensitivity measured by a risk preference task from baseline to follow-up. The task assesses preference for smaller safe rewards versus larger risky rewards.	Baseline, Week 4, Month 3, and Month 6
Change in global cognitive function	Change in global cognitive function measured by the Montreal Cognitive Assessment-Hong Kong Chinese version or English version from baseline to follow-up. Higher scores indicate better global cognitive function.	Baseline, Week 4, Month 3, and Month 6
Change in psychomotor speed	Change in psychomotor speed measured by the Digit Symbol Substitution Test from baseline to follow-up. Higher scores indicate better psychomotor speed.	Baseline, Week 4, Month 3, and Month 6

Collaborators and Investigators

• Sponsor: The University of Hong Kong
• Investigators: Principal Investigator: Albert KK Chung, Department of Psychiatry, The University of Hong Kong

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): August 31, 2028
• Study Completion (Estimated): March 31, 2029

Study Registration Dates

• First Submitted: July 26, 2026
• First Submitted That Met QC Criteria: July 26, 2026
• First Posted (Actual): July 30, 2026

Study Record Updates

• Last Update Posted (Actual): July 30, 2026
• Last Update Submitted That Met QC Criteria: July 26, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: addiction; rTMS; Etomidate
• Additional Relevant MeSH Terms: Compulsive Behavior; Impulsive Behavior; Behavior; Behavior, Addictive; Therapeutics; Magnetic Field Therapy; Transcranial Magnetic Stimulation
• Other Study ID Numbers: UW 26-263

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: This is because of the potential legal consequences to the participants as etomidate abuse in the study locality is considered criminal.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No