New-onset depression after colorectal cancer diagnosis: a population-based longitudinal study.

Introduction: To date, no large studies examining the temporal relationship between colorectal cancer (CRC) and the subsequent development of depressive disorders exist. We aimed to assess the incidence of depression post-colorectal cancer (CRC) diagnosis.

Methods: To conduct this longitudinal study, we searched the large US population-based database, Explorys (IBM), from January 1, 1999, to January 1, 2021. We investigated new-onset depression and its associated mortality as well as the role of the mental health provider post-CRC diagnosis. Confidence intervals were calculated for all outcomes and multivariate regression analysis was performed.

Results: Incident depression post-CRC diagnosis was 20.8 vs 8.9 per 100 person-years [OR 3.46, p < 0.0001] in the general population and conferred a 123% increased risk of all-cause mortality [P < 0.0001]. Male patients (OR: 1.89) were more likely to become depressed post-CRC diagnosis as compared to females. Moreover, the absolute number of male patients with post-CRC depression was significantly higher than that of females (68% vs 32%; P < 0.0001). In addition, depression after CRC was more common among Whites (OR: 1.68) and patients aged > 65 years (OR: 5.17). Referral to a mental health provider resulted in significantly lower all-cause mortality (3.6% vs 26.9%; p < 0.0001).

Discussion: Our findings advocate for initiating depression screening for high-risk patients post-CRC diagnosis and prompt mental health provider referral.