Changes in Depressive Patterns Before and After Lung Cancer Diagnosis: A Nationwide Population‐Based Study

OBJECTIVE: Depression is common among patients with lung cancer, but evidence from large, population-based studies is limited. This study examined antidepressant use and hospital-diagnosed depression before and after lung cancer diagnosis in Denmark. METHODS: We conducted a nationwide registry-based study including all patients diagnosed with lung cancer from 1998 to 2022 and a comparison cohort (1:4 ratio) matched on age, sex, municipality, and marital/cohabiting status. Data on hospital diagnoses and redeemed antidepressant prescriptions were obtained from Danish national registries. RESULTS: Among 73,930 patients with lung cancer and 293,892 matched comparison subjects, antidepressant use was already higher among lung cancer patients two years before diagnosis (12.7% vs. 9.9%) and increased markedly after diagnosis (23.7% vs. 11.9% 2 years post-diagnosis, p < 0.001). Among individuals without prior antidepressant use, 8.4% of patients with lung cancer initiated antidepressants within the first year and 13.7% within the second year, compared with 1.9% and 3.4% of controls (p < 0.001). Hospital-diagnosed depression occurred in 2.1% of lung cancer patients versus 0.8% of controls, with higher rates among females. CONCLUSIONS: Antidepressant use is prevalent before, and rises further after, a lung cancer diagnosis. The difference relative to the comparison cohort was most evident among individuals with no history of antidepressant use. These findings underscore the need for systematic psychosocial assessment and integrated mental health support throughout the lung cancer care pathway.