Major depressive disorder likely among cancer patients

Cancer patients are at a higher risk of developing major depressive disorder (MDD), reports a new Japan study.

Using a medical claims database, researchers conducted a cohort study including 35,008 cancer patients (mean age, 53.3 years; 51.2 percent male) who were followed for the development of MDD. A total of 2,201 (6.3 percent) were eventually diagnosed with MDD within 5 years of cancer diagnosis. Researchers also included a cancer-free control cohort that included 303,720 individuals.

After cohort matching, the incidence of MDD over an 18-month observation period was found to be significantly higher in the cancer vs noncancer groups (3.9 percent vs 1.1 percent; log-rank p<0.001).

This trend was confirmed by multivariate Cox proportional hazards analysis, which found that those with cancer were almost thrice as likely as their comparators to be diagnosed with MDD between 6 months before and 12 months after cancer diagnosis (hazard ratio [HR], 2.96, 95 percent confidence interval [CI], 2.77–3.16).

Moreover, both males and females aged <40 years were more likely to have MDD than comparators between the ages of 40 and 64 years. Across all age groups, females were at a slightly greater risk of MDD than males.

The effect of malignancy on MDD likelihood was also consistent across almost all cancer types, but was strongest in those with multiple cancer types (HR, 5.89, 95 percent CI, 4.76–7.30), pancreatic cancer (HR, 5.45, 95 percent CI, 3.70–8.04), and cancers of the brain or central nervous system (HR, 4.62, 95 percent CI, 2.86–7.51).

“Physicians should watch for MDD in cancer patients for at least 1 year after cancer diagnosis, when the risk of MDD is high, and treat when necessary,” researchers said.