“I have had periods of depression since I was about 15 years old. I have seen a Psychologist and generally my mental health has been pretty good until I got really sick with a cold recently.  It took me a while to get over the physical symptoms and I went through a rough time of depression.  Why would a cold lead to me having depression?” Greg

Thank you for your question Greg. The idea that our minds and bodies are separate is often traced back to Descartes and his idea of mind-body dualism.  He proposed that the mind and body exist as separate entities.  His ideas are permeated throughout science, medicine, and psychology.

Psychoneuroimmunology is the study of the interactions between our psychological processes and our nervous and immune systems.  The idea that our physical and mental health interact developed a few hundred years after Descartes and has been growing in popularity.  Recent research advances in DNA, the immune functioning, and brain science have led to a greater understanding of the interaction between our minds and bodies.

Now we know that our brains and body are connected in multiple ways. “Neurotransmitters, hormones, and neuropeptides have been found to regulate immune cells, and these in turn are capable of communicating with nervous tissue through the secretion of a wide variety of cytokines”. The idea that stress can influence our immune system has been demonstrated in many ways.  These include research which has shown that children who experience more adverse experiences have more health problems in adulthood, animals who have been stressed have reduced ability to fight infection, and people who experience chronic stress develop more inflammatory diseases.

In terms of your situation where you became physically unwell first, we now understand that the immune system can send signals to the brain.  If you think about it the symptoms of depression and sickness are pretty much the same.  Many of the symptoms of a ‘cold’ are in fact our immune response and the related behavioural changes which occur have evolved to help us conserve energy and keep us out of harm’s way to fight the infection.  Runny noses, headaches, fevers and lack of energy are all our symptoms of our immune system fighting off the infection.  Your immune system also has an inflammatory response and releases cytokines which impact the production of neurotransmitters such as dopamine, serotonin, and norepinephrine.  This can cause changes in our mood, alertness, memory, and cognition.

There is still much research needed in this area in a situation like yours there are definitely links between your body’s immune response to a cold and your later symptoms of depression.  My advice would be to ensure you are using the psychological skills that have helped you in the past.  Also ensure you are resting as these symptoms are your body and minds ways of communicating what they need.  If these do not resolve your symptoms of depression it would be useful to book in to see your GP for a physical check-up and also book in with a psychologist to develop further skills to manage your depressive symptoms.

There is a lot of research occurring currently in this area and there are many discoveries still to make which will undoubtedly have enormous benefits for our health and wellbeing.  One area that is particularly exciting is that healthy relationships appear to regulate our immune response and may be able to reduce some of the inflammatory response associated with stress. I will write future blog posts on this topic.