Cancer and depression biochemically linked: Study
POSTED May 19, 2009 - 17:12 | POSTED BY Jyoti Pal
Last edited by Harpreet Bhagrath on May 19, 2009 - 17:52
Cytokines, a chemical produced by tumors, can produce negative mood swings, making cancer patients more apt to become depressive, researchers at the University of Chicago asserted.
Details of the rat study
100 rats, some of whom were bred to have cancer, were picked up for the study. A series of tests were carried out to determine their emotional state.
For the first test, the rats were submitted to a swimming exercise. Rats with tumors were less motivated to try to escape when forced to swim through water as against their non-cancerous counterparts, researchers observed.
For the second test, rats were offered to feast on a sugar water drink, a cocktail that usually attracts the appetites of healthy rats. Rats with tumors were more likely to forgo the drink as opposed to their healthy counterparts, researchers highlighted. “The conditions similar to depression in humans,” researchers marked.
Moreover, rats with tumors recorded increased levels of cytokines in their blood and hippocampus (part of the brain that regulates emotion) when compared with healthy rats.
“Cytokines are produced by the immune system, and an increase in cytokines has been linked to depression” study’s lead researcher, Brian Prendergast, from the University of Chicago, pointed.
Researchers also observed an impaired stress hormone production in rats with tumors. Rats with tumors produced lower levels of corticosterone, a stress hormone which helps regulate the impact of cytokines, researchers revealed.
Human implications
As rats are commonly used to test drugs, especially anti-depressants, to determine their potential human benefits, the findings hold great value, Prendergast averred.
“In this case, examining behavioral responses to tumors in non-human animals is particularly useful because the rats have no awareness of the disease, and thus their behavioral changes were likely the result of purely biological factors.”
"About one in 10 people with cancer get clinical depression and the root causes are likely to be complex, but this study provides an intriguing suggestion that the cancer itself may have a part to play,” he concluded.
The findings of the study feature in the current issue of the journal Proceedings of the National Academy of Sciences.
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