Suicide risk and antidepressant prescriptions among people with cancer: a prefecture-level ecological study

Abstract Background: A previous study has reported regional disparities in suicide risk among individuals diagnosed with cancer in Japan. However, the association between suicide risk and antidepressant prescription remains unexplored. This ecological study aimed to investigate this association at the prefectural level. Methods: Standardized mortality ratios (SMRs) for suicide among individuals with cancer in each prefecture were obtained from published literature. Antidepressant prescriptions were sourced from the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) Open Data, and general suicide rates were calculated using Vital Statistics and Population Estimates of Japan. Prefecture-level correlations were quantified between antidepressant prescriptions per population and SMR for suicide among individuals with cancer, along with general suicide rates. Results: The analysis revealed no significant association between antidepressant prescriptions and SMR among people with cancer. In contrast, significant correlations were observed between antidepressant prescriptions and the general suicide rate. Conclusions: The contrasting findings imply that suicide among individuals with cancer can occur even in the absence of pre-existing psychiatric disorders and might be driven by other factors, such as stress related to the diagnosis and treatment. In addition, clinicians may consider evidence-based nonpharmacological interventions, such as cognitive behavior therapy, rather than antidepressant treatment. Future studies should use individual-level prescription data to validate this hypothesis.