Depression and cancer seem almost inevitable, like the nausea and hair loss from chemotherapy. Indeed, some hospital oncology departments have therapists specially trained to help people facing the uncertainty, pain, and debilitation of their disease. But we assume that depression accompanies or follows the diagnosis of cancer, rather than acting as an early warning symptom.
However, sometimes that early warning symptom of depression is exactly what it is. An individual becomes depressed, the depression is explained as being caused by unresolved emotional and situational problems, the depression is treated, but the individual does not improve. And then, the individual has a sort of a stroke of luck. A physician who knows the individual suspects that maybe something more than depression is wrong with the patient.
Tests are done and it turns out that the individual has cancer. The cancer is successfully treated, and the individual learns the mysterious depression was related to, and perhaps caused by, chemicals that are released in the body by certain types of cancer. These chemicals, called cytokines, affect the brain and, in in some poorly understood way, brought about the depression. Once the cancer is eliminated these chemicals disappear, and with their disappearance, the depression vanishes.
The New York Times published just such a case in the Sunday magazine feature, “Diagnosis.” The author, Lisa Sanders, M.D., described a woman, a psychologist, who found herself experiencing the typical features of a major depression: anehedonia, social isolation (she left her home only to go to her office), irritability, loss of appetite, and difficulty sleeping. The symptoms the article described did not respond to antidepressants, or even an anti-psychotic drug. I know the woman and can attest to her transformation from a beautiful, young for her age, extremely active, verbal, funny and bright person to someone who looked twenty years older than she was, and almost non-communicative.
Fortunately for the patient, my friend, her internist pursued causes for the deterioration of mental and physical well-being, and found that she had ovarian cancer. The cancer was treated successfully and eventually, under the care of a psychiatrist who deals with depression associated with cancer, the patient was reassured that eventually, as she healed, the depression would vanish.
It did. In retrospect, it seems as if the depression, resistant to conventional therapies, saved her life. It turned out to be an early symptom of her cancer, but until she developed physical symptoms such as night sweats, loss of weight, and a general feel of being unwell that her physician took seriously; her depression had been viewed simply as a mood disorder and nothing more. Although her case was sufficiently unique to be written up as a puzzling diagnosis in the Times, cancer researchers have known for many years that there is a strong relationship between depression, anxiety, sleep disturbances and other symptoms of major depression and pancreatic cancer. In an article published in The Scientific World Journal, the authors report that mood disorders such as depression and anxiety, alone or with panic attacks, may even precede the diagnosis of pancreatic cancer. Cytokines, the chemicals thought to have been responsible for my friend’s depression are found in the circulation not only when some types of cancer are present, but also in association with inflammatory illnesses such as multiple sclerosis, a disease known to generate depression as of the symptoms.
Pancreatic cancer patients have been found to have a significantly high incidence of depression; researchers at the Sloan Kettering Cancer Center in New York looked at their cytokine profile to see whether specific cytokines were linked to specific depressive symptoms. They found specific pro-inflammatory cytokines associated with specific symptoms: severe depression, hopelessness, fatigue, sleep disturbances, and pain. There is some research suggesting that cytokines may affect also serotonin release in the brain, thereby triggering depressive symptoms. But the research is still very preliminary.
Interestingly, the individual written about in “Diagnosis” continued to suffer from a severe depression even when taking three antidepressants that increase serotonin activity. Her depression disappeared only when the cytokines disappeared. In some respect, she was fortunate that her depression did not respond to antidepressants because if it had, her cancer may never have been detected. What is new to many of us from this case study is that the appearance of depression may be a red flag indicating the presence of diseases in the body that are still silent, and thereby still without noticeable symptoms. My friend told me that she told her therapist repeatedly that she did not understand why she was depressed. As an experienced therapist herself, she was convinced that something strange was happening to her body not related to the symptoms of depression. But as she said, the feeling of hopelessness, fatigue, sadness, and inertia that came over her made it harder and harder to seek out additional medical help. As the article in the Times mentioned, it was only when her adult daughter urged her to seek medical, and not psychiatric evaluation, did she take the steps that led to the diagnosis of cancer.
This is not to say that depression is always the consequence of underlying diseases producing cytokines that result in mood changes. The reason the case was written was because it was so rare. But it is, as they say, a cautionary tale. Not everything is as it seems, and when depression strikes in an otherwise happy, well adjusted, mentally and physically balanced individual, it might be crucial to see whether there is a cause, like cancer or an autoimmune disease, which is responsible.
“Screening for Depression, Sleep-Related Disturbances, and Anxiety in Patients with Adenocarcinoma of the Pancreas: A Preliminary Study,” Boyd, A., Brown, D., Henrickson, C., et al; 2012; 2012, Article ID 650707, 6 pages
“Depression, cytokines, and pancreatic cancer,” Breitbart, W., Rosenfeld, B., Tobias, K., et al, Psycho-Oncology 2013: Wiley Online Library