PURPOSE: Antipsychotic drugs (APDs) can be used to relieve psychological symptoms in patients with cancer. We investigated the nationwide use of APDs during concurrent chemoradiotherapy (CCRT) for patients with lung cancer and its association with overall survival (OS). MATERIALS AND METHODS: The National Health Service database was used in this retrospective cohort study. Patients diagnosed with lung cancer between 2010 and 2020 who received cisplatin-based CCRT were included. The APDs included in the analysis were aripiprazole, quetiapine, olanzapine, risperidone, haloperidol, and chlorpromazine, and the APD prescription details included prescription time, dosage, and duration. RESULTS: Among the 23,099 patients with lung cancer treated with CCRT, 2,662 (11.5%) took APDs concurrently. Quetiapine (47.3%) and chlorpromazine (36.6%) were the frequently prescribed APDs. In the univariate analysis, patients prescribed APDs during CCRT had a significantly worse OS than those who did not take APDs. The 2-year OS rates for APD (+) and APD (-) patients were 20.4% and 36.4%, respectively (p <
0.001). Multivariable analyses revealed that APD prescription, male, age >
80 years, and comorbidities, such as hypertension, myocardial infarction, and depressive disorder, significantly influenced OS. In patients who used APDs during CCRT, APD prescription timing (pre-CCRT vs. during CCRT), dosage (low vs. high) and duration (within 6 months vs. over 6 months) had no significant difference. CONCLUSION: Overall, 11.5% of patients with lung cancer used APDs during CCRT. Patients who used APDs during CCRT had poorer survival than those who did not. Further studies are required to elucidate the effects of APDs on patients with cancer.