How inflammation in the body could be causing depression

Inflammation in your body could be a factor causing depression, according to a book just published in the U.S. called "The Inflamed Mind: A Radical New Approach to Depression." Author Edward Bullmore, head of the psychiatry department at the University of Cambridge, examines the link between inflammation and mental health.

"We've known for a long time there's an association. Inflammation and depression go together. If you have arthritis, psoriasis, inflammatory bowel disease, for example, all inflammatory diseases in the body, your risk of depression is going to be much increased. The new understanding is that that association could be causal. It's not just a coincidence," Bullmore said Wednesday on "CBS This Morning."

When there are inflammatory cells throughout the body, they can send signals to the brain that change mood and behavior, Bullmore said. But it's important to note that inflammation is not found in all those who suffer from depression, he added.

"We're not talking about a kind of one-size-fits-all solution to depression. I think that's probably been one of the reasons why we've seen so little therapeutic progress in depression over the last 20, 30 years. It's not just one thing," Bullmore said. "I think the inflammatory component is probably going to be important for about a third of patients with depression. And then there are a lot of other patients whose primary diagnosis isn't psychiatric. They may have arthritis, as I mentioned, already. About a quarter of those will also have depression. So it's not everybody. But it's going to be quite a lot of people."

More than 16 million American adults suffer at least one major depressive episode a year, according to the Centers for Disease Control and Prevention. The National Alliance on Mental Illness estimates mood disorders, like clinical depression, are also the third most common cause of hospitalizations in the U.S. for adults between 18 and 44.

Some people might even have inflammatory responses in their bodies but not realize it, which Bullmore referred to as low-grade inflammation – from issues including dental problems, obesity, and social stress.

"There are many factors that wouldn't amount to a disease, wouldn't necessarily have you going to the physician and saying I've got an inflammatory disorder. But if you do a blood test, there would be some evidence," Bullmore said.

He said exercising, reducing stress, and not smoking could all contribute to reducing inflammation in your body.

Now Bullmore wants the health care industry to bridge what he calls a "medical apartheid."  

"I think the way we think about things at the moment with the mind and the body being quite apart, patients going to see different doctors, different hospitals, for treatment of mental and bodily symptoms. I'm not sure that's to the advantage of the patients," he said. "I think we need to break down the barrier between mind and body and thinking about the inflammatory links. And the way that the immune system can communicate from the body to the mind."