Cancer can trigger depression19th May 2009
A recent US-led study shows that depressive tendencies in cancer patients can be explained using biochemistry.
The finding showed that tumours produce chemicals which have been linked to negative changes in mood.
Researchers at the University of Chicago, who came to their conclusions after testing on rats, said that this may be why depression is often a risk for cancer patients.
While it has already been established that cancer is associated with depressions, experts previously thought that this was because of the psychological effect of being diagnosed with cancer.
Some also supposed that it was a side effect of chemotherapy.
But molecules known to have a depressive effect upon brain chemistry are produced in increased quantities by tumours.
While chemicals known to block the effects of these substances play into the brain's chemical reactions, they are blocked by other chemicals produced by tumours.
The substances have a direct effect upon the hippocampus, a part of the brain that deals with emotion.
The researchers employed a test that monitors rats for a condition similar to depression in humans.
They found that, out of 100 rats, those which had cancer were less likely to try to escape the water in a swimming test.
Rats with tumours also displayed less enthusiasm toward sugar water, as well as having increased cytokine levels in their brains and blood.
Cytokines are produced by the immune system, and have been linked to depression at high levels.
The rats also produced lower levels of corticosterone, a substance known to deflect the impact of high cytokine levels.
Brian Prendergast, who led the research team, said that rats are commonly used to test drugs that are being studied for potential human benefits.
He said that, in this case, examining behavioural responses to tumours in non human animals is particularly useful because the rats have no awareness of the disease, so that their behavioural changes were likely to be the result of purely biological factors.
Cancer Research UK senior science information officer Alison Ross said that, since this study looking at cancer and depression was carried out in rats, it was not clear whether the results would hold true in cancer patients.
She said that about one in 10 people with cancer gets clinical depression and the root causes were likely to be complex.
But she said the study provided an intriguing suggestion that the cancer itself may have a part to play.
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Title: Cancer can trigger depression
Author: Luisetta Mudie
Article Id: 11415
Date Added: 19th May 2009