Science / Medicine : Study Backs Mental Illness, Cancer Link

Certain tumors apparently secrete natural opiate-like drugs, a finding that would support the theory that some types of cancer may cause mental illness, researchers say.

In a study published in the New England Journal of Medicine this month, researchers at the University of Maryland School of Medicine in Baltimore found that some types of tumors produced a variety of so-called endogenous opiates.

“If this work is true and is confirmed, certain tumors may cause behavioral manifestations including mental illness,” said David G. Bostwick, pathologist professor who headed the study.

Endogenous opiates are produced naturally by the body and thought to play important roles in the perception of pain, response to stress, regulation of appetite and sleep, memory and learning.

Other researchers have previously reported cases of patients who were suffering from symptoms similar to psychiatric conditions, such as manic depression, whose symptoms disappeared after a tumor was discovered and removed.

In search of a possible cause of this phenomenon, the researchers analyzed tissue from 108 tumors representing more than 20 different types of cancer. They found that some tumors, mostly of the hormonal system, produced these substances.

More study is needed to confirm that the endogenous opiates produced by the tumors are released into the blood and to determine whether they cause any behavioral changes, Bostwick said.

“The work that we have done suggests the possibility that if these tumors can produce these substances, it is probable they can secrete these substances into the blood and have effects throughout the body,” he said.

The findings suggest that in some cases the first symptoms of cancer may be psychiatric problems. Cases have been recorded in which the first sign something was wrong was depression and in which later examinations detected the malignancy.

“The implication here is that tumors may influence behavior and behavior may predate the clinical recognition of the tumor,” he said.

Bostwick added that if his findings are confirmed, they may indicate that patients who have one of these tumors may produce false positive results on tests aimed at detecting the use of illicit drugs.

“If the tumor is secreting the substance into the blood, there may be a false positive,” he said.