Methamphetamine use disorder (MUD) is among the costliest and deadliest substance use disorders (SUDs) world-wide and is frequently comorbid with other mental health conditions. There is no empirically validated medical treatment for MUD. Drug craving is the signature aspect of MUD and other substance use disorders and has been associated with continued drug use and relapse. The investigators and others have shown that transcranial direct current stimulation (tDCS) over dorsolateral prefrontal cortex (DLPFC) can modulate drug craving in different SUDs. tDCS is a method of non-invasive brain stimulation and is a low-cost scalable technology without any serious side effects that delivers low levels of direct current (0.1-2 mAmp) transcranially. However, there are significant inter-individual differences in response to tDCS, which is not well understood but can have profound impact on efficacy. Meanwhile, there are no studies with neuroimaging to show how tDCS affects drug craving. The investigators propose the first combined tDCS/functional Magnetic Resonance Imaging (fMRI) study to examine the acute effects of tDCS on neural substrates underlying drug induced craving. The investigators hypothesize that tDCS amplifies DLPFC's top-down modulatory role via its connectivity to other cortical-subcortical areas. In this double blind randomized experimental design, the investigators will recruit 60 people with MUD during their early abstinence phases into parallel arms with active and sham DLPFC tDCS. Each subject will undergo resting state and task based (drug cue exposure paradigm) functional MRI pre and post tDCS. The investigators will conduct individual difference analyses to explore the potential predictors for tDCS response, including pre-tDCS top-down connectivity measures of DLPFC and other subjective, clinical, behavioral, structural, and functional variables. The results of this study will provide neuroscience-based evidence for the efficacy of tDCS and will advance the field towards precision addiction medicine.
Methamphetamine use disorder (MUD) is among the costliest and deadliest substance use disorders (SUDs) world-wide and is frequently comorbid with other mental health conditions. There is no empirically validated medical treatment for MUD. Drug craving is the signature aspect of MUD and other substance use disorders and has been associated with continued drug use and relapse. The investigators and others have shown that transcranial direct current stimulation (tDCS) over dorsolateral prefrontal cortex (DLPFC) can modulate drug craving in different SUDs. tDCS is a method of non-invasive brain stimulation and is a low-cost scalable technology without any serious side effects that delivers low levels of direct current (0.1-2 mAmp) transcranially. However, there are significant inter-individual differences in response to tDCS, which is not well understood but can have profound impact on efficacy. Meanwhile, there are no studies with neuroimaging to show how tDCS affects drug craving. Investigators propose the first combined tDCS/functional Magnetic Resonance Imaging (fMRI) study to examine the acute effects of tDCS on neural substrates underlying drug induced craving.