Psychiatric Disorders and the Risk of Early and Late Suicide Death Among Patients With Cancer in Taiwan: A National Registry Cohort Study

Objective Patients with cancer have a higher suicide rate compared to the general population. Anxiety and depression are also prevalent among cancer patients. In this nationwide population-based study, we set out to assess the association between psychiatric diagnoses and the subsequent hazard of suicide death among patients with cancer. Methods Participants were selected from Taiwan’s National Health Insurance Research Database between 2010 and 2019. We identified 929,788 eligible adults with a first primary cancer diagnosis, of whom 2319 died by suicide. Suicide death was evaluated within 1 year after cancer diagnosis (early suicide) and more than 1 year after diagnosis (late suicide). We fitted cause-specific Cox models with a psychiatric diagnosis as a time-varying exposure, treating deaths from other causes as competing events. Results Of 929,788 patients, 2319 (0.25%) died by suicide (1035 early and 1284 late). A psychiatric diagnosis recorded after the cancer diagnosis was associated with a higher hazard of suicide death (adjusted hazard ratio [HR] = 5.81, 95% confidence interval [CI] = 4.93-6.74). The association was observed in both the early period (adjusted HR = 6.32, 95% CI = 5.50-7.28) and the late period (adjusted HR = 5.57, 95% CI = 4.65-6.53; P for interaction = 0.001). Depressive disorders had the highest hazard ratio for both early and late suicide death. Conclusions Among patients with cancer, a psychiatric diagnosis recorded after the cancer diagnosis was associated with a higher hazard of suicide death, and this association persisted beyond the first year after diagnosis. These findings support systematic psychiatric screening and ongoing suicide risk assessment throughout cancer care.