Amphetamine Use Disorder (AUD) is a major public health issue in Taiwan, where it is the most commonly abused illegal drug. There are currently no effective approved medications to treat it, which makes finding new treatment options urgent. Repetitive Transcranial Magnetic Stimulation (rTMS), a non-invasive brain stimulation method, has shown promise in reducing cravings and drug use in people with addiction, but its effects on AUD are not well studied.

To explore this, the investigators plan to conduct a double-blind, sham-controlled study with 20 people diagnosed with AUD. Half will receive real rTMS treatment, and half will receive a placebo-like sham treatment. The treatment targets a specific brain area (the left dorsolateral prefrontal cortex) and will be given 10 times over two weeks.

The investigators will assess the effectiveness of rTMS by tracking drug cravings, urine test results, and side effects with follow-up over 12 weeks. The investigators also include brain imaging using near-infrared spectroscopy (NIRS) after the treatment.

The study aims to better understand how rTMS might help reduce amphetamine cravings and improve outcomes, potentially leading to new treatment options for AUD.

Amphetamine Use Disorder (AUD) is a serious and growing public health concern, especially in Taiwan, where amphetamines are the most commonly misused illegal drugs. Globally, amphetamines also rank among the top drugs of abuse. Despite the widespread impact of this condition, there are currently no approved medications that effectively treat amphetamine addiction. This gap in treatment options underscores the urgent need for new and innovative approaches to help individuals struggling with AUD.

One promising method being explored is Repetitive Transcranial Magnetic Stimulation (rTMS). This is a non-invasive technique that uses magnetic fields to stimulate specific areas of the brain. It has already shown positive effects in treating several mental health conditions, such as depression and anxiety, and early studies suggest it may also help reduce cravings and drug use in people with substance use disorders.

This study aims to investigate whether rTMS can help people with AUD by reducing their cravings and improving their chances of recovery. To do this, the investigators will conduct a carefully controlled clinical trial involving 20 participants who have been diagnosed with AUD. The participants will be randomly divided into two groups. One group will receive active rTMS treatment, while the other will receive a "sham" or placebo version of the treatment. This means the second group will undergo the same procedure without the magnetic stimulation, allowing us to accurately measure the true effects of rTMS.

The treatment will focus on a brain area called the left dorsolateral prefrontal cortex (DLPFC), which is involved in decision-making, impulse control, and craving regulation. The rTMS sessions will use a high-frequency setting (15 Hz) delivered in short bursts, with a total of 10 sessions spread over two weeks.

To understand the impact of the treatment, the investigators will collect several types of data from participants throughout the study (pre and post) and for 12 weeks afterward. This includes:

Urine drug tests to check for ongoing amphetamine use Craving assessments to see if the urge to use drugs decreases Monitoring for side effects to ensure safety Neuropsychological tests to assess changes in thinking and behavior Brain imaging using near-infrared spectroscopy (NIRS) to observe changes in brain activity Through this comprehensive approach, the investigators hope to learn more about how rTMS works in the context of amphetamine addiction and whether it could be developed into an effective treatment. The findings could pave the way for new, science-based therapies to support individuals with AUD and reduce the burden of this condition on individuals, families, and society.

Inclusion Criteria:

• Age ≥20 years.
• Meeting DSM-5 criteria for substance use disorder made by a specialist in addiction psychiatry.
• Fluency in Chinese.
• Willingness and ability to comply with study requirements.
• Good physical health determined by complete physical examination, and laboratory tests.
• Patient or a reliable caregiver can be expected to ensure acceptable compliance and visit attendance for the duration of the study.
• Trained psychiatrists will assess eligible patients using the structured clinical interview for the Mini-International Neuropsychiatric Interview (MINI) (Sheehan et al., 1998) to determine the presence of any psychotic disorder.

Exclusion Criteria:

• Evidence of an uncontrolled and/or clinically significant medical condition, e.g., cardiac, hepatic and renal failure that would compromise patient safety or preclude study participation.
• Premorbid mental retardation.
• Other major Axis-I Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) diagnoses other than substance use disorder.
• Pregnancy or nursing.
• History of seizures or epilepsy.
• History of neurological diseases or traumatic brain injury.
• Suicidal attempts or risks during screening or study period.
• Presence of prosthesis devices, e.g. pace-makers, cochlear prosthesis, neuro- stimulators, magnetic cochlear prosthesis, intraocular metallic fragments.