Objective: To evaluate the efficacy of electroacupuncture (EA) for the treatment of anxiety and depression in unmarried patients with polycystic ovarian syndrome (PCOS) by secondary analysis of a randomised controlled trial. Methods: A prospective pilot randomised controlled trial of unmarried women with PCOS was conducted from November 2012 to March 2016. Participants were assigned to the acupuncture group (receiving EA for 16 weeks) or the control group (receiving sham acupuncture for 16 weeks), with 27 patients in each group. The pre-specified primary outcomes and all secondary outcomes, with the exception of serum levels of neurotransmitters including norepinephrine (NE), epinephrine (AD), serotonin (5-HT) and.-aminobutyric acid (GABA), will be reported separately. Additional outcome measures selected for this secondary analysis included anxiety and depression scale scores (Zung-SAS and Zung-SDS), 36-Item Short Form (SF-36) scale scores, PCOS Quality of Life (PCOSQOL) scale scores and Chinese Quality of Life (CHQOL) scale scores. Results: After the16-week intervention, an increase in serum NE and reduction in 5-HT were observed in the acupuncture group (P= 0.028 and P= 0.023, respectively). The serum level of GABA decreased in both groups after the interventions (both P< 0.001). However, there were no significant differences between the two groups in the levels of any neurotransmitters (p> 0.05). After EA treatment, SAS and SDS scores were decreased in the acupuncture group (P= 0.007 and P= 0.027, respectively) and were lower than those of the control group (P= 0.003 and P= 0.004, respectively). The SF-36 domain scores for mental health, vitality, social functioning, general health and health transition, the total CHQOL scores, and the infertility problems and body hair domains of the PCOSQOL improved significantly after EA (P< 0.05). Conclusion: EA appears to improve symptoms of anxiety/depression and quality of life in PCOS patients and may influence serum levels of NE and 5-HT. These findings should be interpreted with caution, given the secondary nature of the outcome measures reported herein.