Mood Disorder Risk High Among Colorectal Cancer Patients

Patients with colorectal cancer are at a higher risk for mood disorders such as depression, bipolar disorder, and anxiety—especially if the follow-up time is greater than 1 year—according to a new report.

Researchers from Arrowhead Hospital in Arizona and medical centers in Taiwan included <27,000 colorectal cancer patients to assess the risk for mood disorders in this cohort. The patients were identified through the Taiwanese National Health Insurance Research Database between January 1, 2000, and December 31, 2010. The patients were then matched from the general population based on age, sex, and index year/month to create the control group.

Mood disorders were more prevalent in the colorectal cancer group compared to the control group by about 15%, the researchers determined. Compared to the healthy control group, colorectal cancer patients were about 1.5 times more likely to have a depressive disorder, about 4 times more likely to develop bipolar disorder, and 3.81 times more likely to develop an anxiety disorder. The risks for these mood disorders remained similar throughout the 4 different levels of urbanization, the study authors wrote.

The researchers also discovered differences in mood disorder rates that were dependent on follow-up period time. When colorectal cancer patients experienced a follow-up within 1 year, they had a significantly higher risk for mood disorder and anxiety disorders, but a lower risk for depressive disorders compared to healthy controls. If the follow-up period reached more than 1 year, patients with colorectal cancer experienced higher risks of mood, bipolar, and anxiety disorders compared to the healthy cohort.

Another factor was radiotherapy: Colorectal cancer patients receiving radiotherapy had a lower risk of mood and anxiety disorders compared to colorectal cancer patients not undergoing radiotherapy. Patients receiving chemotherapy had a lower risk of mood and anxiety disorders compared to patients not receiving chemotherapy.

The study authors theorized that the relationship between the different treatment options and prevalence of mood and anxiety disorders was due to the trust and reliance on physicians by patients in Taiwan.

“More treatments may present more opportunities for patients to meet with their physicians regularly, which may have positive effects to the patients’ mental health substances,” Dr. Li-Min Sun (photo) told MD Magazine in an e-mail. “Sometimes not receiving treatment leads to more anxiety and distress because patients perceive nothing is being done about the cancer.”

The researchers added that other studies examining different cancers and psychiatric disorders determined, in general, that a high prevalence of disorders was present in adult cancer patients. They also pointed to a 1997 University of Texas study that estimated that prevalence of depressive symptoms in colorectal cancer patients was 24%. However, in this study, depression among colorectal cancer patients was 2.7%. This can be attributed to different diagnostic criteria, the researchers wrote.

“Oncologists should acknowledge this phenomenon and recommend colorectal cancer patients to have mental evaluations as well as early detection and treatment for potential psychological problems,” the study authors concluded, adding, “Some types of cancer related treatments, however, may reduce this risk with certain unexplored underlying mechanisms.”

The study, titled “Risk of Mood Disorders in Patients with Colorectal Cancer,” was published in the Journal of Affective Disorders.

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