The fresh focus that the coronavirus pandemic has thrown on the vital importance of our immune systems may have already prompted you to make certain changes to your lifestyle to help to improve your body’s ability to fend off infection and disease.
Some such alterations that one could make – including adopting a steady exercise regime and boosting consumption of fruit and vegetables – received plenty of publicity even before COVID-19.
What you might not have necessarily appreciated, though, is that mental health also belongs in the conversation about how to strengthen your immune system – in more ways than you may think.
Why shouldn’t our psychological state be linked to our bodily health?
In some ways, the debate about mental health and immunity probably shouldn’t centre on whether the two are connected, but more on why we ever doubted this association in the first place.
For that, you might initially blame the 17th-century French philosopher René Descartes, whose thinking – including the mantra “I think, therefore I am” – helped to establish a longstanding perception of disconnect between the mind and the body.
Such widespread presuppositions meant that as even as recently as two decades ago, very few people would have expected the immune system and brain to have anything to do with each other.
Many of us, though, have long had an instinctive sense that the two entities are linked. After all, flu sufferers also often show depressive symptoms such as social withdrawal, fatigue, difficulties with concentration, malaise, and loss of appetite. These adaptive “sickness behaviours” are triggered by immunological chemical messengers that circulate around our bodies and instruct us to prioritise rest and recovery.
Indeed, the issue wasn’t always a lack of awareness of the connection between mental health and immunity, but instead insufficient knowledge of the relevant biological mechanisms. As Professor Solveig Merete Klæbo Reitan of the Norwegian University of Science and Technology (NTNU)’s Department of Mental Health has previously observed, “Most people have had the sense of this connection, but as doctors we haven’t quite kept up”.
But it’s no longer controversial to acknowledge it
The mere evidence that people with mental disorders are also at greater risk of various body inflammations and immune-system disorders is enough to indicate that our immune responses are related to our mental health in some way.
However, other studies down the years have shed further light on why it is such a sensible connection to make. There was the research published in Neuron in 2018, for instance, which found that mice repeatedly exposed to stress showed an immune response that released inflammatory proteins. Such inflammation resulted in atrophy and impaired brain responses, which in turn brought about depressive behaviours.
Some years earlier, a team of scientists led by the University of Cambridge uncovered evidence of mental illness and chronic physical illness potentially sharing common biological mechanisms. More specifically, the study – published in JAMA Psychiatry – found that children with high everyday levels of a protein released into the blood in the wake of infection were also more susceptible to developing depression and psychosis in adulthood.
There is doubtless much more for us to learn about the body dynamics driving the connection between immunity and mental health, and there is certainly more to the topic than simply “thinking your way” to good health. So, we can expect no shortage of fresh experimental research aimed at further breakthroughs. In the words of Klæbo Reitan: “We’ll have to wait and see.”