The connection between inflammation and depression explained

With new evidence suggesting that depression can be linked to inflammation in the body, we explain why a healthy lifestyle is key to combating psychological stress

C-reactive protein, molecular model. The protein is made up of five sub-units (monomers) arranged in a ring. The secondary structure of the protein is shown, with beta sheets (arrows) and alpha helices (spirals) connected by linking regions. C-reactive protein (CRP) is a blood plasma protein produced by the liver. It is an acute phase protein, one whose levels rise in response to inflammation. It assists the binding of complement proteins to foreign or damaged cells, an immunological response that destroys the target cells. High blood levels of CRP are associated with increased risk of heart disease and diabetes.
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When people come to the therapists at The LightHouse Arabia in Dubai for help, there's a common pattern to their complaints.

In addition to suffering symptoms of acute or chronic stress, they often report an assortment of physical ailments, whether it’s muscle or joint pain, respiratory issues or gastrointestinal distress. They are sure they are suffering from anxiety or depression, are in a crisis, overwhelmed and don’t know what to do. 

When this happens, and it happens all the time, explains Dr Saliha Afridi, clinical psychologist and a managing director at the centre, the first order of business for their therapist is to bypass the mind and work on stabilising the body. “This is just something that as psychologists, we know,” she says. “It’s an assumption that we make, that you are going to have inflammation in your body.”

When she starts to explain what is going on, something usually clicks with the patients. And, most often, once stabilised, they feel much better. "We're looking at the symptoms of yes, they meet the criteria for depression," explains Afridi. "But I think if you took underneath those symptoms, a lot of that has to do with an unhealthy lifestyle, inflammation of the body, difficulties in relationships, chronic stress, and poor sleep patterns, and if you manage for those, the depressive symptoms almost always manage themselves. Usually the depression lifts off."

When cortisol is lowered, serotonin is raised, other biological functions are working better and the body's chemistry is more in balance, patients can feel strong enough to tackle whatever problems sparked their stress in the first place, whether it's a difficult workplace or personal relationship or something else. 

For years, scientific research has been mounting that prolonged psychological stress causes the body to lose its ability to regulate inflammation, and when it rises, the brain suffers. The links between inflammation and depression are being found at a variety of levels, most recently last month in a study on individuals with major depressive disorders, who have experienced suicidal thoughts. According to researchers from the UK's University of Manchester, they carried higher levels of a protein marker for inflammation, compared to healthy people. 

"The evidence for a link between depression and inflammation is quite compelling now, and there is also mounting evidence for a link between suicide and inflammation across a range of mental disorders," explains Dr Peter Talbot, the lead investigator. "If we can learn more about these links, it may lead to more effective prevention or treatments of depression and suicidal thinking by targeting aspects of the inflammatory process."

Among the growing body of research was a 2016 study published in the Journal of Clinical Psychiatry. It collected data from American national health and nutrition surveys conducted between 2007 and 2012, and concluded that there was a connection between several inflammatory indicators – C-reactive protein and nitric oxide, a marker for airway inflammation – and depression. Increasingly, doctors are looking into the gut-brain axis, or the consistent, ongoing interplay between the gut and the brain, says Dr Nas Al-Jafari, a family medicine consultant and co-founder of Intercare Health Centre in Abu Dhabi.

Creating a healthy micro-biome will have a knock-on effect on psychological symptoms, which is one of the reasons for the rise in probiotic use and an emphasis on lifestyle. After all, it was Hippocrates himself who said: “Let food be thy medicine and medicine be thy food.”

"Whether there are issues with sleep, the day/night cycle, issues with high stress, a problem with the diet, or a lack of exercise – correcting all these things would help people with depression," Al-Jafari says. There is a role for medication and psychological therapy when someone quite clearly has had a major depressive episode, he says. "But I would say that most people don't fall into a major depressive episode and don't need medication. Far fewer people probably need to go on medication than are being medicalised." 

That's the point Dr Kelly Brogan drives home in her recent book A Mind of Her Own. The American holistic women's health psychiatrist assessed years of scientific research to conclude that depression can result from a chemical imbalance in the body, not the mind. "We owe most of our mental illnesses – including their kissing cousins such as chronic worry, fogginess, and crankiness – to lifestyle factors and undiagnosed physiological conditions that develop in places far from the brain, such as the gut and the thyroid," she writes. "That's right: you might owe your gloominess and unremitting unease to an imbalance that is only indirectly related to your brain's internal chemistry." 

She criticises conventional medicine for its "medicalisation of distress", where the drive for profit through marketing influences serious decisions – such as turning to antidepressants, which have lasting consequences.

She argues that while medication may provide an initial lift, it’s often not necessary and can do more damage than good in the long-term – and not just due to the known side effects. “The dirtiest little secret of all is the fact that antidepressants are among the most difficult drugs to taper from, more so than alcohol and opiates,” she writes.

Brogan’s prescription involves a four-week plan to clean up the diet, eliminating alcohol, sugar and caffeine; a series of blood and urine tests to uncover possible conditions not normally on general medicine’s radar; a supplement regime, movement and sleep. 


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Maha Abdellatif, a Tunisian who teaches conversational Arabic, is behind the 280-strong Facebook group In Your Shoes, which was launched to help people in Abu Dhabi talk about depression, anxiety and mental health. Those who have experienced serious depression know that it requires more than a change in diet and a bit of extra exercise to counter the symptoms. Yet Abdellatif has also been following mounting research about the inflammation-depression link, and is familiar with the immediate impact of ingesting inflammatory items on her body and mind.

"With sugar and Red Bull, within an hour, I feel like I'm getting stressed out, and caffeine for sure makes me stressed out," says Abdellatif. " A number of people in the group try to maintain a healthy diet, because it really does make a difference. I don't think it's just impacting depression or anxiety, it's the whole body – chemicals, hormones and everything."

Once people are aware of the inflammation-depression connection, they can learn how to spot the signs early, and take action on their own, avoiding larger emotional and even physical problems, says Afridi. 

"I always tell people we all have ups and downs that we go through, and there are periods where we might feel anxious and depressed," she explains. "But when those periods come on, usually the behaviour that follows is we start eating poorly, sleeping poorly, stop exercising, and that worsens those symptoms. So the minute you start to feel you have depressive symptoms or anxiety symptoms, just so you don't get worse, you [should] immediately move to: 'How can I take care of the physical body?'

“Don’t even try to tackle the thoughts at this time, don’t even try to take a more balanced mindset. At this point, you should just be thinking: ‘What can I be sure to do to make sure I’m eating foods that don’t cause inflammation?’”