Depression - a new explanation?

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Depression has existed for centuries and according to the World Health Organization it’s the leading cause of disability worldwide. (Ref1) That’s quite something. And yet despite being so prevalent, it’s still remains hard to talk about- but I bet you know someone who is struggling with sadness, hopelessness and a loss of interest. Or perhaps you know quite a few of them, or maybe you’re struggling with it yourself. 

Throughout history people have come up with numerous possible explanations for the causes of depression. Few people these days would probably suspect demonic possessions or a brain disorder or assume that you have inherited a weakness that can never be changed. Likewise, there have been many different kinds of treatments, ranging from exorcisms, bloodletting and electroconvulsive therapy to herbal remedies, exercise, travel, change in diet and psychotherapy to name a few. These days, millions of sufferers use antidepressant drugs and in fact, the use of those is at an all-time high: 64.7million items of antidepressant drugs were handed out in England in 2016. That’s nearly 50% more than 10 years ago! (Ref2)

Antidepressants were first introduced in the 1950’s and today’s most commonly used ones date back to the 1980’s. They rest on the belief that depression stems from a chemical imbalance and as such all these drugs target neurotransmitter availability in the brain- you may have heard about some of them, such as serotonin or dopamine which help make you happy.

With these drugs being used in such vast quantities they must clearly be helping a lot of sufferers, and yet as many as 40-60 out of 100 people may not notice any improvements to their symptoms at all. And it is widely known that there is a risk of suicidal thoughts as a side effect for children and teenagers. So whilst they help many, others are do not gain any benefits...

The rise of a new theory- the inflammatory hypothesis

Since the early 1990’s, a growing number of scientists are now suggesting that, at least for a substantial subgroup of sufferers, depression may actually result from inflammation caused by the immune system. This idea is quickly gaining attention and perhaps you’ve even read about it in your newspaper:“Are we thinking about depression all wrong?” (Telegraph) or “Could a runny nose make you depressed? Hay fever sufferers may be four times more likely to develop the mental illness” (Daily Mail). 

These days we hear a lot about inflammation. It seems such a negative term and yet it’s actually a vital response by our immune system to keep our body alive and healthy.  If we injure ourselves or catch an infection, our immune system responds by triggering an inflammatory response: It sends out chemical messengers to sites of infection and trauma. Some of these messengers, for example cytokines, cannot only raise inflammation (or lower it depending on the type) but they also play an important role for our brain development and functioning- influencing our mood, behaviour and cognition.

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There have now been numerous studies that looked at this link between inflammation and depression and it’s fascinating: Quite a few studies, for example, have shown that depressed people have higher levels of these cytokines than people without depression. (Ref3) And in another study, healthy subjects were given inflammatory cytokines and were then found to have developed symptoms of depression!(Ref4)

So depression may actually be stemming from chronically high levels of inflammation in the body- perhaps not for all people but certainly for a group of sufferers. 

And of course there’s now a lot of research going on into the use of anti-inflammatory drugs for the treatment of depression. So far, some of these look very promising with sufferers experiencing a reduction in their symptoms after using drugs that lower inflammation. (Ref5) 

Suppressing inflammation in the body via the use of drugs is one way to potentially help people with depression. Another approach, one that Nutritional Therapists would focus on, would be to look at what might actually be causing raised levels of inflammation in the first place. And the issue of chronic inflammation in the body is not something new: Plenty of conditions are related to it, such as arthritis, heart conditions, auto-immune illnesses and many others. 

So I do believe there is hope for people who have so far not been able to get better through other ways. Depression can of course be complex and multi-factorial in its causes, and a varied approach is likely best, but this new thought that depression may actually be linked to inflammation in the body opens up great new possibilities.


Very soon I shall be writing more about raised inflammation in the body: What might be causing it? What effects can it have? So come back soon if you’re interested to find out more!


  1. http://www.who.int/mediacentre/factsheets/fs369/en/

  2. http://content.digital.nhs.uk/article/7756/Antidepressants-were-the-area-with-largest-increase-in-prescription-items-in-2016

  3. http://www.biologicalpsychiatryjournal.com/article/S0006-3223(09)01229-3/fulltext

  4. http://www.jad-journal.com/article/S0165-0327(09)00091-3/fulltext

  5. https://www.statnews.com/2016/01/28/inflammation-depression

Claudia SmithComment