BACKGROUND: Polycystic ovary syndrome (PCOS) is one of the common gynecological endocrine diseases. The morbidity of PCOS coexists with many psychological problems, such as depression, anxiety, decreased confidence, and severe insomnia. PCOS patients suffer from diminished physical health and quality of life. However, the psychological problems related to PCOS are usually overlooked by clinicians. CASE: An unmarried, 24-year-old woman with a 4-year history of amenorrhea was diagnosed with PCOS. She participated in a clinical trial studying acupuncture for the treatment of PCOS. She was randomly assigned to the sham acupuncture group and experienced significantly shortened average menstrual cycles, from 183.75 days to 35.75 days. CONCLUSION: The changes in mental emotions may be the critical factor which triggered a series of changes in this case. Psychological problems may be the main factors of PCOS-related morbidity, and psychological counseling may be effective in PCOS patients with psychological problems or who were originally negatively affected by psychological factors.