Aspirin and other non-steroidal anti-inflammatory drugs and depression, anxiety, and stress-related disorders following a cancer diagnosis: a nationwide register-based cohort study

BACKGROUND: Cancer patients have a highly increased risk of psychiatric disorders following diagnosis, compared with cancer-free individuals. Inflammation is involved in the development of both cancer and psychiatric disorders. The role of non-steroidal anti-inflammatory drugs (NSAIDs) in the subsequent risk of psychiatric disorders after cancer diagnosis is however unknown. METHODS: We performed a cohort study of all patients diagnosed with a first primary malignancy between July 2006 and December 2013 in Sweden. Cox proportional hazards models were used to assess the association of NSAID use during the year before cancer diagnosis with the risk of depression, anxiety, and stress-related disorders during the first year after cancer diagnosis. RESULTS: Among 316,904 patients identified, 5613 patients received a diagnosis of depression, anxiety, or stress-related disorders during the year after cancer diagnosis. Compared with no use of NSAIDs, the use of aspirin alone was associated with a lower rate of depression, anxiety, and stress-related disorders (hazard ratio [HR], 0.88; 95% confidence interval [CI], 0.81 to 0.97), whereas the use of non-aspirin NSAIDs alone was associated with a higher rate (HR, 1.24; 95% CI, 1.15 to 1.32), after adjustment for sociodemographic factors, comorbidity, indications for NSAID use, and cancer characteristics. The association of aspirin with reduced rate of depression, anxiety, and stress-related disorders was strongest for current use (HR, 0.84; 95% CI, 0.75 to 0.93), low-dose use (HR, 0.88; 95% CI, 0.80 to 0.98), long-term use (HR, 0.84; 95% CI, 0.76 to 0.94), and among patients with cardiovascular disease (HR, 0.81; 95% CI, 0.68 to 0.95) or breast cancer (HR, 0.74; 95% CI, 0.56 to 0.98). CONCLUSION: Pre-diagnostic use of aspirin was associated with a decreased risk of depression, anxiety, and stress-related disorders during the first year following cancer diagnosis.