Anxiety and depression linked to higher cancer death risk

Psychological distress is associated with an increased risk of death from some cancers, according to an analysis of UK health data. Authors of the study,* published online today by The BMJ, said their findings added to the growing evidence of an association between psychological distress and physical conditions, but called for further testing with alternative study designs to explore the extent to which these associations might be causal.

A team of researchers from University College London, the University of Edinburgh, and the University of Sydney examined the role of psychological distress (anxiety and depression) as a potential predictor of site-specific cancer mortality. To do so they analysed data from nationally representative samples drawn from the health survey for England (13 studies) and the Scottish health survey (three studies). These data covered 163,363 men and women aged 16 or older at study induction in 1994 to 2008, who were initially free of a cancer diagnosis, had provided self-reported psychological distress scores (based on the general health questionnaire, GHQ-12) and had consented to health record linkage.

During the period covered by the study there were 16,267 deaths (4,353 from cancer) among participants. The researchers adjusted for several potentially influential factors such as age, sex, education, socioeconomic status, body mass index (BMI), smoking and alcohol intake – and also allowed for the possibility of reverse causality, i.e. undiagnosed cancer negatively affecting mood – and still found that, relative to people in the least distressed group (GHQ-12 score 0-6), those in the most distressed group (GHQ-12 score 7-12) had consistently higher death rates for cancer of all sites combined (hazard ratio (HR) 1.32) and cancers unrelated to smoking (HR 1.45).

Psychological distress was also significantly associated with higher risk of death from specific cancers including carcinoma of the colorectum (HR 1.84), prostate (2.42), pancreas (2.76), oesophagus (2.59), and for leukaemia (3.86). For both colorectal and prostate cancers, the study authors found that the greater level of distress, the higher the risk of cancer mortality.

They suggested several possible explanations for their findings, pointing out that mood disorders such as depression have been implicated in immune pathways and are known to provoke inflammatory responses – and prolonged immune dysregulation can compromise exposed cells’ repair capacity, potentially contributing to genetic instability and mutations, alterations in DNA repair, and inhibition of apoptosis. They added that people who are distressed might be less likely than others to comply with requests for screening so they are diagnosed later; and, once cancer is diagnosed, depression might hamper adherence to treatment.

They concluded: “Our findings add to the growing evidence of an association between psychological distress and physical conditions by characterising new relations with death from selected cancer presentations. The extent to which these associations could be causal requires further testing with alternative study designs.”