Transcranial electrical stimulation for depression with chronic pain

Inclusion Criteria:

1. Meets the diagnostic criteria for a depressive episode (DSM-5);
2. HAMD-17 score of ≥8 and ≤23 (mild-to-moderate depressive symptoms) based on the current assessment;
3. 4 or higher on Item 5 of the Brief Pain Inventory (BPI), and persistent pain lasting more than three months;
4. Ages 18-80;
5. Right-handed, with normal hearing, vision, or corrected vision;
6. Have a high school education or higher and be able to understand and complete research-related assessments;
7. Maintain a consistent regimen of analgesic and antidepressant medications and psychotherapy (including dosage and type of medication or treatment method) for four weeks prior to enrollment;
8. The subject (or his or her legal representative, if applicable) signed an informed consent form stating that he or she understood the purpose and procedure of the trial and was willing to participate in it.

Exclusion Criteria:

1. Diagnosed according to the DSM-5 as meeting any of the following criteria: ① Major depressive disorder or treatment-resistant depression (HAMD-17 score ≥ 24, and the current episode has lasted ≥ 2 years, or the current episode has been unresponsive to treatment with ≥ 2 antidepressants); ② Schizophrenia spectrum disorder; ③ Bipolar I disorder; ④ Anxiety disorders (including generalized anxiety disorder, panic disorder, social anxiety disorder, etc.); ⑤ Depressive disorder caused by a medical condition.
2. Experiencing malignant pain caused by cancer pain syndrome, visceral pain (such as stomach pain), referred pain (such as back pain caused by pancreatitis), and so on;
3. Patients with severe or unstable physical illnesses, including but not limited to: neurological disorders (such as epilepsy, stroke, migraine, history of cranial surgery, etc.); neurological disorders accompanied by structural brain abnormalities (e.g., traumatic brain injury, recent stroke, brain tumor); cardiovascular diseases (e.g., uncontrolled hypertension, heart failure, arrhythmias, myocardial infarction, etc.); respiratory diseases (e.g., severe sleep apnea syndrome); malignant tumors or immunodeficiency; uncontrolled diabetes (fasting blood glucose \> 12 mmol/L);
4. Excessive alcohol consumption within 30 days prior to the start of the trial, or a history of alcohol or drug dependence within the past 6 months;
5. Women who are pregnant, breastfeeding, or planning to become pregnant within 3 months of the start of the trial;
6. Currently taking medications that affect cortical excitability (e.g., benzodiazepines, antiepileptic drugs);
7. Have undergone neurostimulation therapy within the past 3 months, including electroconvulsive therapy (MECT), repetitive transcranial magnetic stimulation (rTMS), or transcranial electrical stimulation (tES);
8. Suffers from claustrophobia and is unable to undergo an fMRI scan (applies to subjects who require a functional MRI scan);
9. Contraindications to transcranial electrical stimulation (such as intracranial metal implants, pacemakers, cochlear implants, skin abrasions at the stimulation site, or a personal or family history of epilepsy, etc.);
10. Currently participating in another clinical trial, has participated in a clinical trial within the past 90 days, or plans to participate in another clinical trial during the study;
11. Participants with obvious suicidal tendencies, impulsive behavior, or an inability to cooperate with study evaluators;
12. Accompanied by psychotic symptoms;
13. Researchers believe there are other circumstances that make a participant unsuitable for the trial;
14. Patients with severe cognitive impairment (MMSE ≤ 17) were excluded;
15. Participants who are unable to cooperate with the study;
16. Those who voluntarily withdrew midway.