Closed-loop transcranial temporal interference stimulation (tTIS) targeting the nucleus accumbens may modulate abnormal neural responses to drug-related cues in individuals with methamphetamine use disorder (MUD), thereby reducing drug craving and improving cognitive and behavioral control. Stimulation will be delivered in real time according to each patient's cue-induced response time.
This project will recruit individuals with methamphetamine use disorder. Participants will receive closed-loop transcranial temporal interference stimulation targeting the nucleus accumbens once daily for five consecutive days. During each intervention session, participants will be exposed to methamphetamine-related cues, and stimulation will be triggered according to their response time. Before and after the intervention, clinical questionnaires and behavioral tasks will be administered to evaluate changes in drug craving, methamphetamine-use-related symptoms, inhibitory control, and reward-related decision-making. Cue-induced neural responses will also be assessed to investigate the neural mechanisms through which closed-loop tTIS targeting the nucleus accumbens may alleviate craving and improve addiction-related cognitive and behavioral dysfunction.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
50
Each session will comprise 240 trials, during which stimulation may be triggered up to 10 times according to the participant's cue-reactivity state. Each stimulation will consist of a 5-s current ramp-up, 30 s of continuous stimulation, and a 5-s current ramp-down. The intervention will be administered once daily for five consecutive days.
The stimulation parameters-including frequency, current intensity, and duration-are identical to those in the active group. However, the sham stimulation mode is activated on the device, resulting in consist of a 5-s current ramp-up, but 0 s of continuous stimulation during the stimulation.
Shanghai Mental Health Center
Shanghai, Shanghai Municipality, China
Change of Craving
Visual Analog Scale, range0-100 point. the higher the score, the more one wants drugs.
Time frame: baseline, 1 day after treatment, 1 month after treatment
Obsessive-Compulsive Drug Use Scale score
Drug-related obsessive thoughts and compulsive behaviours will be assessed using the Obsessive-Compulsive Drug Use Scale (OCDUS). The scale consists of 14 items rated from 0 to 4, producing a total score ranging from 0 to 56. Higher scores indicate more severe drug-related obsessive thoughts, craving, and impaired control over drug use.
Time frame: baseline, 1 day after treatment, 1 month after treatment
Dual-Mode of Self-Control Scale-Impulsive System score
Impulsive tendencies will be assessed using the Impulsive System subscale of the Dual-Mode of Self-Control Scale (DMSC-S). The subscale contains 12 items rated from 1 to 5, producing a total score ranging from 12 to 60. Higher scores indicate stronger impulsive-system tendencies, including greater impulsivity, distractibility, and preference for immediate gratification.
Time frame: baseline, 1 day after treatment, 1 month after treatment
Dual-Mode of Self-Control Scale-Control System score
Self-control will be assessed using the Control System subscale of the Dual-Mode of Self-Control Scale (DMSC-S). The subscale contains 9 items rated from 1 to 5, producing a total score ranging from 9 to 45. Higher scores indicate stronger self-control, including better problem-solving and future-oriented planning.
Time frame: baseline, 1 day after treatment, 1 month after treatment
Stop Single Task
Response inhibition will be assessed using the Stop-Signal Task. The primary behavioural parameter will be the reaction time and accuracy, measured in milliseconds. A longer stop-signal reaction time indicates poorer inhibitory control, whereas a shorter stop-signal reaction time indicates better inhibitory control.
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Time frame: baseline, 1 day after treatment, 1 month after treatment
EEG ERP amplitude during the Stop-Signal Task
The mean amplitude of the stop-related event-related potential and functional connection will be measured in microvolts over frontocentral electrodes within the prespecified post-stimulus time window.
Time frame: baseline, 1 day after treatment, 1 month after treatment
Decision-making Preferences and Delay of Gratification
delay discounting task,Delay of gratification will be assessed using a computerised delay-discounting task in which participants choose between smaller immediate rewards and larger delayed rewards. The discounting-rate parameter, k, will be estimated from participants' choices. A higher k value indicates steeper delay discounting, a stronger preference for immediate rewards, and a lower ability to delay gratification.
Time frame: baseline, 1 day after treatment, 1 month after treatment
Changes in Reward Learning
Reward learning will be assessed using a computerised reinforcement-learning task. A computational reinforcement-learning model will be fitted to participants' trial-by-trial choices. The learning-rate parameter, alpha, ranges from 0 to 1 and represents the extent to which recent feedback is used to update expected values. Higher values indicate greater updating in response to recent feedback.
Time frame: baseline, 1 day after treatment, 1 month after treatment
sensitivity to reward and punishment
Sensitivity to punishment will be assessed using the Sensitivity to Punishment subscale of the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ). The subscale contains 24 dichotomous items scored 0 or 1, producing a score ranging from 0 to 24. Higher scores indicate greater sensitivity to punishment.
Time frame: baseline, 1 day after treatment, 1 month after treatment
Behavioral Inhibition/Activation System Scale
Sensitivity to anticipated punishment will be assessed using the 7-item Behavioural Inhibition System subscale of the Behavioural Inhibition System/Behavioural Activation System Scales. Each item is rated from 1 to 4, producing a score ranging from 7 to 28. Higher scores indicate greater behavioural inhibition and sensitivity to anticipated punishment.
Time frame: baseline, 1 day after treatment, 1 month after treatment
Beck Depression Inventory-II score
Depressive symptom severity will be assessed using the Beck Depression Inventory-II (BDI-II). The inventory consists of 21 items rated from 0 to 3, producing a total score ranging from 0 to 63. Higher scores indicate more severe depressive symptoms.
Time frame: baseline, 1 day after treatment, 1 month after treatment
Drug-cue Flanker task
Attentional interference from methamphetamine-related cues will be assessed using a computerised drug-cue Flanker task. The drug-cue attentional interference effect will be calculated as the difference in mean reaction time between trials containing methamphetamine-related cues and trials containing neutral cues, measured in milliseconds. A larger positive value indicates greater attentional interference from methamphetamine-related cues.
Time frame: baseline, 1 day after treatment, 1 month after treatment
EEG theta power
Theta-band power will be quantified within the prespecified frequency range, electrode region, and post-stimulus time window. The cue-related theta effect will be calculated as the difference between methamphetamine-related and neutral cue conditions. A larger value indicates a stronger theta-band response to methamphetamine-related cues.
Time frame: baseline, 1 day after treatment, 1 month after treatment
EEG P3 amplitude
Task-related electroencephalography will be recorded during the drug-cue Flanker task and the reward learning task. The mean amplitude of the P3 event-related potential will be measured in microvolts within the prespecified electrode region and post-stimulus time window. A larger positive difference indicates greater neural reactivity to methamphetamine-related cues.
Time frame: baseline, 1 day after treatment, 1 month after treatment