Depression, Anxiety Linked to Increased Risk of Developing Lung, Smoking-Related Cancers

Depression and anxiety were thought to increase a person’s risk of developing cancer; however, new research indicates that is not the case. A study published in Cancer evaluated 18 patient cohorts who struggled with either depression or anxiety. Patients would follow up with physicians at 5, 10, 15, and 20 years to examine whether they had cancer (e.g., overall, breast, lung, prostate, colorectal, alcohol-related, and smoking-related cancers).¹

Depressed, anxious woman | nenetus | stock.adobe.com

Previously, experts had suspected that depression and anxiety may increase the risk of cancer either because of the effect of mental health individuals’ health-related behaviors or biological effects on the body that potentially support cancer development. Although some research had supported an association between depression, anxiety, and cancer incidence, other investigations found no association or no insignificant associations.²

Further, covariates including weekly alcohol intake, antidepressant use, body mass index (BMI), hours of physical activity per week, smoking status, and family history of cancer were taken into consideration, with study results being adjusted if necessary.¹

The study consisted of 2 stages, with the first stage using Cox regression models in each cohort, and the second stage combining results in random-effects meta-analyses. Depression and anxiety were conceptualized and analyzed based on diagnoses (clinical interviews or results scoring above a clinically validated cutoff on self-report questionnaires) and symptoms (assessed by self-report questionnaires). Participants who either had a history of cancer or had cancer were excluded, unless it was (nonmelanoma) skin cancer.¹

Results indicate that anxiety and depression were not associated with an increased risk of overall cancers (e.g., breast, prostate, colorectal, or alcohol-related cancers); however, the presence of depression or anxiety was associated with a 6% higher risk of developing lung cancer and smoking-related cancers. This risk was substantially reduced after adjusting for other cancer-related risk factors including smoking, alcohol use, and BMI. The study results support the importance of addressing tobacco smoking and other unhealthy behaviors including those that may develop as a result of anxiety or depression.²

The lack of association between anxiety and depression and all cancers is inconsistent with previous meta-analyses, which is likely due to the higher consistency in covariates included in the current study’s models across all cohorts, the unlikely presence of publication bias in meta-analyses, and the current study’s large sample size, according to the authors. Additionally, cancer diagnosis was based on registry information in all cohorts, meaning that data on malignancy, site, and time of diagnosis were influenced less by recall bias.¹

Other subtypes of cancer (e.g., non-small cell lung cancer) were not considered in the study. Further, the researchers note that data on anxiety and depression were patient-provided, and that more chronic forms may be at a higher risk of cancer.¹

The results from the study may help health professionals alleviate any feelings of guilt in self-blame in patients with cancer who blame previous depression or anxiety for their diagnosis.

“Our results may come as a relief to many patients with cancer who believe their diagnosis is attributed to previous anxiety or depression,” said Lonneke A. van Tuijl, PhD, of the University Medical Center Groningen, in a press release. “However, further research is needed to understand exactly how depression, anxiety, health behaviors, and lung cancer are related.”²

References

1. van Tuijl L, Basten M, Pan K, et al. Depression, anxiety, and the risk of cancer: An individual participant data meta-analysis. Cancer, 2023. doi.org/10.1002/cncr.34853

2. Wiley. Robust analysis challenges theory that depression and anxiety cause cancer risk. News release. August 7, 2023. Accessed on August 8, 2023.