The Link Between Depression and Pancreatic Cancer

Annette Stanton, Ph.D., and Michael Irwin, M.D.

Effective and affordable screening protocols for pancreatic cancer do not yet exist. In fact, most people don’t visit a doctor until the disease begins producing visible symptoms, such as unexplained weight loss and jaundice.

But what if there was an early indicator of the disease? What if symptoms such as depression, sleep disturbance, and anxiety could tip people off that something is seriously wrong? While psychological symptoms are often a reaction to the disease and anxiety about treatments, experts increasingly believe they may also be a product of the disease process. In addition, there may be a very specific link with pancreatic cancer.

Depression Before Pancreatic Cancer Diagnosis

Pancreatic cancer and depression go hand-in-hand. But it’s not just because a pancreatic cancer diagnosis—and the rigorous treatment that often follows—is distressing. In fact, a growing body of research suggests depression may be an early warning sign of the disease.

“Cancer produces profound biological effects on the body, which can alter behavior,” explains Michael Irwin, M.D., Cousins Distinguished Professor of Psychiatry and Biobehavioral Sciences at David Geffen School of Medicine at UCLA (Los Angeles). “When immune cells go in and try to destroy the cancer, an inflammatory response is triggered in the body, and such inflammation can contribute to the onset of depressive and anxiety symptoms, as well as sleep problems.”

That inflammation has adaptive goals—it makes us tired, it reduces our appetite, and it may alter our sleep patterns. Add it all together and it’s no wonder depression often precedes a cancer diagnosis. Let’s look at the facts:

• In a 2016 study of 300,000 cancer patients and more than 3 million cancer-free individuals (controls), researchers from Sweden reported an increased risk of psychiatric illness nearly one year before cancer patients were diagnosed. And the mental disorders were more common for cancers with poor prognoses.
• Studies show up to 78% of pancreatic cancer patients experience depression, a much higher percentage than in people who have other cancers.
• Two literature reviews, one from 1993 and one from 2014, report that between 33% and 45% of pancreatic cancer patients experienced psychiatric symptoms before medical symptoms. The relationship is so striking, some clinicians think depression could become a testable marker for pancreatic cancer.

“Pancreatic cancer seems to be especially susceptible to pre-diagnosis depression, probably because the pancreas secretes mood-stabilizing hormones, neurotransmitters, and digestive enzymes—and pancreatic cancer is a rapidly growing cancer that produces a strong inflammatory response,” suggests Irwin.

Even giving people immune cytokines (the inflammatory substances our immune system produces when we’re on high alert) in the lab can produce a “sickness behavior” syndrome within minutes that looks something like this:

• Fatigue
• Anxiety
• Sleep disturbance
• Appetite loss
• Impaired cognition

That constellation of symptoms applies to both cancer and depression.

A Double Hit

Depression and anxiety tend to co-exist with a number of health conditions—and not everyone who has depression should undergo testing for pancreatic cancer.

“When medical and mental health professionals are aware of the relationship between pancreatic cancer and depression, especially when they’re examining people who have never suffered from depression previously and are over age 50, they may be able to identify pancreatic cancer at earlier stages of the disease and potentially save thousands of lives,” Irwin explains.

Depression After Pancreatic Cancer Diagnosis

Jeopardy! host Alex Trebek went public about suffering from depression during pancreatic cancer treatment. The latest research seems to suggest the overwhelming sadness Trebek describes isn’t a result of treatment, but rather part of the disease process—that depression is one of few visible symptoms of pancreatic cancer.

Increasingly, health authorities are recognizing the importance of mental health screening for everyone—not just people who are diagnosed with cancer. In 2016, the U.S. Preventive Services Task Force issued guidelines recommending routine screening for depression among the adult population. Such screening is simple, painless, and takes only a few minutes using validated scales such as the Patient Health Questionnaire and the Hospital Anxiety and Depression Scales. The hope is, when depression is present, it will cue clinicians to probe more deeply rather than just prescribe an antidepressant.

“Whether or not depression is a signal of pancreatic cancer, depression is important in its own right,” says Annette Stanton, Ph.D., a professor in the Departments of Psychology and Psychiatry/Biobehavioral Sciences at UCLA. “Just because you are depressed doesn’t mean you have cancer and effective treatments for depression are available.”

Already diagnosed with pancreatic cancer? Ask your doctor about depression screening. Treating your depression could help you weather the side effects that come with cancer treatment, bolster your response to therapy, and improve your quality of life.