Univariate analysis showed that receipt of ovarian function suppression (OFS) and/or aromatase inhibitor (AI) therapy, pain, fatigue, anxiety, and depression were associated with exacerbated sleep disturbance, while multivariate analysis revealed that each 1-point increase in pain, fatigue, and depression scores was independently associated with a 23.7%, 25.0%, and 23.7% higher risk of severe sleep disturbance, respectively.<h4>Conclusion</h4>Sleep disturbance is highly prevalent and severe in breast cancer patients, with difficulty falling asleep as the core feature. The gene discussed is CYP19A1; the disease is depressive disorder.