Scientists link tumours to depression
Studies using rats have linked chemicals released by tumours with depression.
Cancer patients often become depressed once diagnosed. This is often put down to the psychological effect of finding out the bad news. However, this new study suggests that this depression could be caused by chemicals released by the tumour, which then travel to the brain.
The team conducted tests on about 100 rats, some of whom had cancer. They used a swimming test, commonly used to measure depression, and found that the rats with tumours were less motivated to escape than those who did not have cancer. Rats are good models in this case, as they are not aware that they have the disease, therefore the depressive behaviour cannot be attributed to psychological issues.
Looking at blood samples and brain studies of the rats, the team saw the animals with tumours had higher levels of chemicals called cytokines. Cytokines are chemicals produced by the immune system which are known to increase with disease. A study earlier this month looking at mice with inflammatory disease linked an increase in cytokines with depression, due to the action of their metabolites.
This discovery could form a target for medications, designed specifically to prevent depression in cancer sufferers.