The purpose of this study is to assess impact of repetitive transcranial magnetic stimulation (rTMS)+Episodic Future Thinking (EFT) vs. sham rTMS+EFT on delay discounting and methamphetamine (MA) demand, on vividness of future positive events during EFT training and on frequency of episodic thinking during the week following EFT training
Meet Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for primary methamphetamine use disorder
Be fluent in English and able to understand the consent form
Current DSM-5 diagnosis for any illicit substance use disorder other than methamphetamine and marijuana
Current DSM-5 diagnosis of moderate or greater severity for alcohol and marijuana use disorder
In the opinion of the PI, the presence of any medical, neurological, psychiatric (e.g., psychotic or bipolar disorder), or physical condition, disease, or illness that, may: (a) compromise, interfere, limit, effect or reduce the subject's ability to complete the study; or (b) adversely impact the safety of the subject or the integrity of the data
Structured Clinical Interview for DSM-5 (SCID-5)
Parallel
EFT
BehavioralParticipants will identify three personalized and rewarding future events not related to drug use that take place 1 week, 1 month, and 6 months in the future. Participants will be asked to rate the vividness of each personalized future positive event on a 5-pt Likert scale.A brief and personalized EFT prompt will be created for each future event . Personalized EFT prompts will be presented during delay discounting and MA demand assessments following EFT training. Participants will also receive daily text/email messages with these prompts, reminding them to engage in EFT, vividly reexperience their future events, over the week following EFT training.
high frequency rTMS
DeviceTMS will be delivered with a MagVenture Mag Pro R30 with the Cool-B70 A/P coil with active liquid cooling . For dlPFC, we will measure position F3. The first session will begin with the acquisition of the resting motor threshold on the contralateral hand. Intermittent theta burst stimulation (iTBS) (triplet 50 Hz bursts, repeated at 5 Hz, 2 sec on and 8 sec off; 600 pulses per session) will be delivered at 110% of the resting motor threshold (RMT) and will last \~3 minutes. Participants will receive 2 sessions of iTBS to the dlPFC brain region with a 15-20-minute interval between sessions
sham frequency rTMS
DeviceParticipants will receive sham TMS to the dlPFC. They may feel the TMS from the A/P coil electrodes, but there will not be any real stimulation of the brain.
Rate of delay discounting as assessed by the 5-Trial adjusting Delay Discounting Task
This 5 item questionnaire measures the extent to which participants devalue a reward as the delay to its receipt increases.This task presents choices between $500 now vs. $1,000 after a delay.The discount rate k quantifies how rapidly the value of a delayed reward decreases with time.Low k Indicates patience or low impulsivity - greater willingness to wait for larger rewards.High k Indicates impatience or high impulsivity - preference for immediate rewards over delayed ones.
Change in MA Demand as assessed by the Drug Purchasing Task
MA demand will be assessed by asking participants how many grams of MA they would purchase to use over the course of a weekend (Friday night to Sunday night) as a function of increasing price ($0 to $10000) Demand is the maximum quantity of Methamphetamine consumed if the drug was free measured in grams or dollar amount
EFT Vividness as assessed by the Vividness Scale
This is a single item questionnaire and is scored on a 5-point Likert scale from 1(not vivid at all) to 5( extremely vivid) for a maximum score of 5, higher score indicating more vivid outcome
EFT Engagement as assessed by the Engagement Scale
This is a single item questionnaire and is scored on a 4-point Likert scale 1-4 asking how often each individual engaged in EFT (i.e., every day, most days, some days, no days), higher score indicating more engagement
Change in prospective memory as assessed by the Prospective and Retrospective Memory Questionnaire (PRMQ)
This is a 16 item questionnaire and each is scored on a 5-point Likert scale from 1(never) to 5(very often) for a maximum score of 80, higher score indicating better outcome
Change in prospective memory (PM) as assessed by the behavioral PM task
The percentage of correct target identifications on the PM task
Number of days of Methamphetamine use as assessed by the time line follow back (TLFB) method
Amount of Methamphetamine used in grams as assessed by the time line follow back (TLFB) method
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