Mental Health Blog

Depression | is it a reaction to inflammation?

Written by MaryAPRN.com/ Advanced Practice Psych LLC | Thu, Mar 31, 2016 @ 03:30 PM

Depression, the stigma associated with it brings many to see it as a weakness vs. anything else, so what if….

  • If it was determined that it was a physical illness?
  • Would that make it less of a issue to admit to?
  • Does that make it… all in the mind?
But what if it actually has a physical cause that could be treated with anti-inflammatory drugs such as aspirin and ibuprofen, or even antibiotics?

This is the fascinating possibility being explored by Scientists at Cambridge University. They suggest their research (in a significant number of cases) depression could be caused by long-term inflammation in the body.

The idea has been gathering credibility over the past few years among researchers worldwide. Indeed, the association between low mood and bodily inflammation caused by infections should be familiar to anyone who has ever had a cold and felt miserable, listless and tired.

According to a growing number of scientists, this is exactly how we should be thinking about the condition. George M. Slavich, a clinical psychologist at the UCLA Laboratory for Stress Assessment and Research in Los Angeles, has spent years studying depression, and has come to the conclusion that it has as much to do with the body as the mind. “I don’t even talk about it as a psychiatric condition any more,” he says. “It does involve psychology, but it also involves equal parts of biology and physical health.”

The basis of this new view after digging in makes it quite obvious: everyone feels miserable when they are ill. That feeling of being too tired, bored and fed up to move off the sofa and get on with life is known among psychologists as sickness behavior. It happens for a good reason, helping us avoid doing more damage or spreading an infection any further.

This looks a lot like depression. So if people with depression show classic sickness behavior and sick people feel a lot like people with depression – might there be a common cause that accounts for both?

The answer to that seems to be yes, and the best candidate so far is inflammation – a part of the immune system that acts as a burglar alarm to close wounds and call other parts of the immune system into action. A family of proteins called cytokines sets off inflammation in the body, and switches the brain into sickness mode.

Tim de Chant of NOVA writes: “Inflammation is our immune system’s natural response to injuries, infections, or foreign compounds. When triggered, the body pumps various cells and proteins to the site through the blood stream, including cytokines, a class of proteins that facilitate intercellular communication. It also happens that people suffering from depression are loaded with cytokine .” Cytokines, known to promote inflammation, are increased in the bodies and brains of people who are contemplating or have attempted suicide.

Some think the inflammatory response may be spurred by an infection of some kind. Others think obesity or modern high-trans-fat, high-sugar diets could be the cause. Still others say that stress from bullying, rejection, or loneliness may be to blame.
  • In 2013, for example, investigators at Aarhus University, in Denmark, examined the health records of nearly 3.6 million people and found that those who had inflammation caused by autoimmune conditions, such as arthritis or Crohn’s disease (inflammation of the lining of the digestive system) were 45 percent more likely to suffer from a depressive condition.
Furthermore, those who had ever been in hospital for a serious inflammatory infection, such as sepsis or hepatitis, were 62 per cent more likely than normal to suffer from a depressive disorder, according to the study published in the journal JAMA Psychiatry.

Eleanor Morgan of VICE adds: “Both cytokines and inflammation have been shown to rocket during depressive episodes, and – in people with bipolar – to drop off in periods of remission..

Healthy people can also be temporarily put into a depressed, anxious state when given a vaccine that causes a spike in inflammation. Brain imaging studies of people injected with a typhoid vaccine found that this might be down to changes in the parts of the brain that process reward and punishment.”

As evidence like this continues to stack up, it’s not surprising that some people have shifted their attention to what might be causing the inflammation in the first place. Turhan Canli of Stony Brook University in New York thinks infections are the most likely culprit, and even goes as far as to say that we should rebrand depression as an infectious – but not contagious – disease.

To call it inflammation, others aren’t willing to go that far, not least because infection is not the only way to set off inflammation. A diet rich in trans fats and sugar has been shown to promote inflammation, while a healthy one full of fruit, veg and oily fish helps keep it at bay. Obesity is another risk factor, probably because body fat, particularly around the belly, stores large quantities of cytokines.

Add this to the fact that stress, particularly the kind that follows social rejection or loneliness, also causes inflammation, and it starts to look as if depression is a kind of allergy to modern life – which might explain its spiraling prevalence all over the world as we increasingly eat, sloth and isolate ourselves into a state of chronic inflammation.

If that’s the case, prevention is probably the place to start. It’s not a great idea to turn off inflammation entirely, because we need it to fend off infections, says Slavich, but “lowering levels of systemic inflammation to manageable levels is a good goal to have”.

There are also others who think we should re-brand depression altogether as an infectious disease … Carmine Pariante, a King’s College psychiatrist who said:

“People with inflammatory diseases such as rheumatoid arthritis tend to suffer more than average with depression; cancer patients given a drug called Interferon alfa , which boosts their inflammatory response to help fight the cancer, often become depressed as a side-effect.. We are between five and ten years away from a blood test that can measure levels of inflammation in depressed people.”

And as for the stigma – could it really be altered by shifting the blame from the mind to the body? Time will tell.

  • This is not the first time that depression has been linked to a physical phenomenon, after all. A recent survey found that despite wider awareness of the theory that “chemical imbalances” in the brain cause depression, this has done nothing to reduce stigma; in fact, it seemed to make matters worse.

This time, though, the target is not any kind of brain or mind-based weakness but a basic feature of everyone’s body that could strike anyone down given the right – or wrong – turn of events. And if that doesn’t inspire a greater sympathy and understanding, then nothing will.

By treating the inflammatory symptoms of depression — rather than the neurological ones — researchers and doctors are opening up an exciting new dimension in the fight against what has become a global epidemic.