Investigate the association between antidepressants and colorectal cancer in a large national sample.

Higher cumulative dose of mirtazapine was associated with a decreased incidence of colorectal cancer.

Selective serotonin reuptake inhibitors, tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, and serotonin antagonist and reuptake inhibitors were not associated with increased incidence of colorectal cancer.

Key strengths of the study were the nationally representative sample, the longitudinal analysis, and the range of covariates considered including various other medication.