This is a randomized controlled and patient-and-assessor-blind trial. A total of 112 participants will be enrolled from the outpatient Acupuncture and Moxibustion Department of the First Affiliated Hospital of Guangzhou University of Chinese Medicine. The flow chart is shown in Fig. 1. The protocol is composed based on the SPIRIT checklist  and the Declaration of Helsinki . The trial was approved by the Ethics Committee of the First Affiliated Hospital of Guangzhou University of Chinese Medicine (K014) and has been registered at the Chinese Clinical Registry (ChiCTR2100046604).
According to preliminary trials [20, 21], we chose the HAMA score as the outcome to calculate the sample size. After treatment, the HAMA score of MA was 14.0±3.2, and the HAMA score of PA was 19.4±5.3. PASS version 15.0 (NCSS, LLC. Kaysville, UT, USA) was used to estimate the sample size with a power level of 90% and a two-sided significance level of 5%. After calculation, we set the sample size of 44 patients in each group to observe the significant difference between the two groups. With a 20% withdrawal rate, we plan to enroll a total of 112 patients with 56 patients in each group.
Randomization and allocation concealment
An independent researcher sets a random number as a seed and used IBM SPSS Statistics version 26 (IBM SPSS Inc., Chicago, USA) to generate a random allocation sequence. According to the size of the random number sequence, patients who received the first 56 random numbers will be allocated into the MA group, and patients who received the last 56 random numbers will be allocated into the PA group in a 1:1 ratio. The researcher will put the cards with written random numbers and group assignments into sealed envelopes. The intervenors will allocate enrolled patients into the MA group or PA group on the basis of the card in the envelope.
Due to the nature of acupuncture, it is difficult to blind patients and intervenors at the same time. We designed a new placebo acupuncture needle pedestal to blind patients, and the pedestal was applied for a patent in China (202121352221.7). The new placebo needle can be used at different positions with the acupoints and at different needling angles (Fig. 2). The PA group used a special needle (φ0.30 × 40 mm, produced by Huanqiu Co. Ltd., China) in which the tip is blunt so that the needle could not be pricked into the skin. In addition, the diameter of the blunt needle is 0.3 mm. It is thin enough to make patients feel like they are pricked. The pedestal is opaque so patients would not know whether the needle is pricked. Therefore, patients are unaware of whether they receive MA or PA. In addition, there is adhesive tape below the base to ensure that the whole pedestal can adhere to the head and body (Fig. 3). To test the participant-blinding effects, the first two patients will be randomly selected from the study to guess whether they have received MA or PA within 5 minutes after one of the treatment sessions in weeks 2 and 4. In addition, researchers who analyze the data are unaware of group assignments either to minimize the potential source of bias.
A total of 112 GAD patients will be recruited through, but not limited to, posters pasted in the hospital lobby and social media (WeChat), which can be seen by potential patients. Meanwhile, we will cooperate with the gynecology and psychology departments of the hospital for potential patients to ensure the target sample size is reached. Eligible patients who meet the inclusion criteria and exclusion criteria will be enrolled in the outpatient department of the First Affiliated Hospital of Guangzhou University of Chinese Medicine.
Patients who meet all of the following criteria will be allowed to enrollment:
Aged 45 to 55 years old (female only).
Meet the diagnostic criteria of DSM-5  for GAD.
Excessive anxiety and worry (apprehensive expectation), occurring more days than not for at least 6 months.
The individual finds it difficult to control the worry.
The anxiety and worry are associated with three (or more) of the following six symptoms (with at least some symptoms having been present for more days than not for the past 6 months):
Restlessness or feeling keyed up or on edge.
Being easily fatigued.
Difficulty concentrating or mind going blank.
Sleep disturbance (difficulty falling or staying asleep, or restless, unsatisfying sleep).
The anxiety, worry, or physical symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.
The disturbance is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication) or another medical condition (e.g., hyperthyroidism).
The disturbance is not better explained by another mental disorder (e.g., anxiety or worry about having panic attacks in panic disorder).
The score of HAMA is between 14 and 28.
No anti-anxiety drugs or other psychotropic drugs in the last 2 weeks.
No participation in any other research in the last 1 month.
Patients who meet any of the following criteria will be excluded:
Diagnosed by other severe illnesses such as heart failure, tumors, renal failure, and so on.
Diagnosed by psychotic illness such as schizophrenia, agoraphobia, and so on clearly.
Addicted to alcohol or drugs in the past 3 months.
Afraid of acupuncture.
Pregnancy or breastfeeding.
Drop out criteria
Patients who meet any of the following criteria will be excluded from the study:
Cannot complete all treatment sessions.
Outbreaks of serious illness threatening life include disability, cancer, organ failure, and so on.
Unwilling to comply with acupuncture treatment.
Anti-anxiety drugs or other psychotropic drugs were administered when enrolled in the study.
Pregnancy when enrolled in the study.
Patient quits the study treatment by herself.
All eligible patients will receive 12 sessions of MA or PA (4 weeks, three times a week). Each session will take 30 min. The acupuncture therapists have acupuncture education from Guangzhou University of Chinese Medicine (range 1–3 years of full-time academic studies) or have clinical experience in the First Affiliated Hospital of Guangzhou University of Chinese Medicine (range 2–5 years). In addition, all intervenors are trained to completely understand the standard of operation. The acupoints of the MA and PA groups are the same, including Sishenzhen (one of the main acupoints in Jin’s 3 Needle ), Shenting (DU24), Yintang (DU29), Shenmen (HT7), and Sanyinjiao (SP6). The acupoint locations are according to the “2006 People’s Republic of China National Standard” (GB/T1234-2006) with the exhibition in Fig. 4. The acupuncture operation will be performed according to the textbook of the 10th Five-Year Plan of the Ministry of Health. Enrolled patients will be treated one-on-one by a trained acupuncturist from beginning to the end. In addition, an independent assistant will follow the intervention procedures to ensure the consistency of treatment.
Patients in the MA group will be pricked by disposable, stainless steel needles (φ0.30 × 40 mm, produced by Huanqiu Co. Ltd., China) through our device. The needles will be inserted into the skin to ensure that patients have a Deqi sensation  which is considered the essential reason for the efficacy of acupuncture . Depth of puncture is approximately 25–30 mm. The needles will be manipulated three times (at the start, middle, and end of every session) by twirling and lifting until the Deqi sensation occurs.
Placebo acupuncture (PA) group
Patients in the PA group will receive placebo acupuncture in which the needles will not be inserted into the skin and will not induce the Deqi sensation. The blunt-tipped placebo needle (φ0.30 × 40 mm, produced by Huanqiu Co. Ltd., China) can provide participant-blinding effects with a similar appearance to conventional needles but no skin penetration.
The schedule of the whole procedure is shown in Fig. 5. An independent assessor who does not know the group assignment will collect outcome data for analysis.
The primary outcome of this study is the HAMA  score, which measures the severity of anxiety. The HAMA is a 14-item scale rated on a 4-point scale with a total score ranging from 0 to 56. A higher score means a higher range of anxiety. According to studies, a score higher than 28 indicates severe anxiety, a score between 28 and 21 indicates moderate anxiety, a score between 20 and 14 indicates mild anxiety, and a score lower than 14 indicates no anxiety. HAMA will be assessed on the first day, the 14th day, and the 28th day of the trial.
The secondary outcome of this study is the GAD-7  score, which measures the severity of GAD particularly. The GAD-7 is a 7-item scale rated on a 3-point scale with a total score ranging from 0 to 21. In addition, the GAD-7 score indicates the level of general anxiety. The higher the GAD-7 score is, the more anxious the patient is. If the patient is enrolled, GAD-7 will be assessed on the first day, the 14th day, and the 28th day of the trial.
The secondary outcome of this study is the PSQI  score, which measures the quality of sleep in the last month. The PSQI is a 19-item questionnaire, divided into 7 parts: sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. The PSQI score is inversely proportional to the quality of sleep. PSQI will be assessed on the first day, the 14th day, and the 28th day of the trial.
CORT and ACTH
It has been suggested that anxious subjects demonstrate greater CORT and ACTH concentrations . In this study, we will draw serum samples and investigate CORT and ACTH before and after acupuncture. An enzyme-linked immunosorbent assay (ELISA) will be used to measure CORT and ACTH. These related tests will be carried out by the clinical laboratory of the First Affiliated Hospital of Guangzhou University of Chinese Medicine.
Researchers will record body temperature, respiratory rate, pulse rate, and blood pressure on the first day, the 14th day, and the 28th day of the treatment. Adverse events (AEs) caused by acupuncture should be truthfully recorded in case report forms (CRFs). In addition, intervenors should treat patients with AEs as soon as possible to comfort patients and eliminate AEs. In the meanwhile, we will inform AEs to the Ethics Committee of the First Affiliated Hospital of Guangzhou University of Chinese Medicine. After treatment of AEs, researchers will ask patients whether they would like to continue the trial or not and respect their will.
Ancillary and post-trial care
After the whole treatment, patients who received PA treatment will receive 12 sessions of MA treatment to compensate. If patients who receive MA treatment want to continue treatment, they can appoint and be treated in the outpatient department.
After the completion of 12 sessions of acupuncture, we will follow patients via telephone or WeChat to score the HAMA, GAD-7, and PSQI scores in the first month and the third month to determine whether the efficacy can be maintained.
Data monitoring and analysis
Data will be saved on paper as recorded by the assessors. All original data will be stored in the medical record room of the First Affiliated Hospital of Guangzhou University of Chinese Medicine for 3 years. An independent assistant will monitor the process of collecting data and the Ethics Committee of the First Affiliated Hospital of Guangzhou University of Chinese Medicine will carry out audits at regular intervals.
Two independent study assistants will input the data, check by themselves whether the input data have discrepancies, and correct them. IBM SPSS Statistics version 26 (IBM SPSS Inc., Chicago, USA) will be used to analyze the data. The HAMA, GAD-7, and PSQI scores assessed in each group will be subjected to normality tests. If the scores obey a normal distribution, a one-way analysis of variance will be performed. If not, the Kruskal-Wallis rank sum test will be performed. The repeatedly assessed HAMA, GAD-7, and PSQI scores in the MA or PA group will be subjected to a normality test. If the scores obey a normal distribution, repeated measurement analysis of variance will be performed. If not, the Friedman rank sum test will be performed. If the significance of the F-test of the univariate linear model is greater than 0.05, CORT and ACTH will be subjected to covariance analysis. If not, the Kruskal-Wallis rank sum test will be performed.
All statistical tests will be two-sided, and the significance level will be set at 0.05. If the patient drops out, we will follow the intention-to-treat (ITT) and use the last score or serological indices assessed as the final score or indices.
Two independent study assistants will input the data to avoid mistyping. Before the beginning of the trial, all intervenors will be trained, and another assistant will follow the intervention procedures and stay in the outpatient department to ensure consistency of acupuncture intervention among intervenors. In addition, quality inspectors will check the CRFs randomly to ensure that there are no recorded errors.