The purpose of this research is to evaluate the efficacy of multiple sessions of theta-gamma cross-frequency transcranial alternating current stimulation in patients with methamphetamine (MA) use disorders.

Previous evidence suggests that different aspects of cognitive function are associated with activities of distinct EEG frequency bands. Gamma oscillatory has been found in clinical studies to reflect the processing of rewards in patients with drug dependence, whereas medial prefrontal theta oscillatory characterizes prefrontal response inhibition capacity to downstream reward arousal. Interestingly, impaired response inhibition or impaired evaluation of rewards in patients with drug dependence have been found to correlate with the arousal of psychological craving and the emergence of relapse. Here we aim to find causal evidence supporting these previous correlational findings by applying cross-frequency transcranial alternating current stimulation (tACS) in the specific frequency bands (theta-gamma) previously shown to be addiction-relevant. In a randomized control clinical trial design, we stimulate subjects with either theta-gamma or sham tACS. Electroencephalography will be collected before and after each treatment session. Besides, the scale and behavior task data will also collected before and after the treatment.

Inclusion Criteria:

1. In accordance with the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) for methamphetamine (MA) use disorders
2. Normal vision and hearing
3. Dextromanual
4. Use MA not less than 1 year, and the last of MA use no less than 3 months

Exclusion Criteria:

1. Have a disease that affects cognitive function such as a history of head injury, cerebrovascular disease, epilepsy, etc
2. Have cognitive-promoting drugs in the last 6 months
3. Other substance abuse or dependence in recent five years (except nicotine)
4. Meet the DSM-5 criteria for other mental disorders
5. Physical disease