Objective: Animal studies have suggested that some antidepressant medications may act as breast tumor promoters and recent epidemiologic studies of antidepressant use and breast cancer outcomes in humans have also reported such associations.
Design: Retrospective cohort study.
Study population: 38,273 women who filled a prescription for any of a number of antidepressants and 32,949 who filled a prescription for any other medication during 1989-1991; all were > or =20, enrolled in Medicare, Medicaid or the Pharmaceutical Assistance to the Aged and Disabled (PAAD) programs of New Jersey, and free of evidence of breast cancer.
Data collection: Antidepressant use was assessed over a period lasting up to 24 months. Subjects were followed for a maximum of 7.5 years; those who had a first diagnosis of breast cancer in the New Jersey Cancer Registry at least 3 months after their index date were considered incident breast cancer cases. Other covariates, including demographic, clinical, and health care utilization variables were also assessed. MAIN OUTCOME OF INTEREST: Adjusted hazard ratio (HR) of developing breast cancer, based on multivariable proportional hazards models.
Results: Use of antidepressants was unrelated to the development of breast cancer (adjusted HR = 1.04; 95% CI 0.87-1.25). No elevated risks were found for specific antidepressants, including agents found to be breast tumor promoters in animal studies, as well as drugs thought to be associated with breast cancer in prior epidemiologic studies. There was no suggestion that breast cancer risks were increased with more intensive use of antidepressants or that antidepressant use is associated with a more severe stage of cancer at diagnosis.
Conclusions: Despite recent reports from much smaller epidemiologic studies or laboratory animals, these results provide reassurance that antidepressant use is not associated with the development of breast cancer.