I’ve been reading some things recently about the links between physical and mental illness, specifically the apparent desire to prove the validity of mental illnesses by claiming they have a physical cause.  And such a claim is not without evidence.  A google search of suitable terms will give up hundreds of articles that cite various links between things like inflammation and depression, depression and chemical imbalances in the body, long term illness and feeling down, being sick and feeling grumpy etc. etc.


In vogue at the moment seems to be the desire to prove that mental illness is not in your head at all, with statements such as – “it’s not psychological, it’s physical”, “psychiatry is useless” and “just change to this particular faddy diet and you’ll be cured” all to be found with only a cursory browse through some of the text.  But when you read a little deeper it seems that the authors conveniently skipped the class on cause and effect.


Lets give an example.  In a particular play park, the slide is very high.  Children from the park who state that the slide is their favourite thing to play on frequently come off the park with bruises or broken bones.  Children who never use the slide never bruise or break anything.  This is a relatively simple case to establish – the slide is too easy to fall off and causes most of the injuries…….  or is it?  Is the slide too dangerous?  Or are the children who are drawn to a very high, slippery, slide, naturally more adventurous and drawn to potentially hazardous activities?  Does the slide actually cause accidents or would those children have accidents anyway?


Cause and effect is easy to assume.  It’s less easy to prove.


So with mental illness having a physical cause.  It’s pretty obvious that being sick makes you feel lousy. You don’t want to move from the sofa or bed, you aren’t interested in doing much or talking much or eating very much even.  You just want to be left alone.  “Hey, these sound like symptoms of depression” someone might say.  “I wonder if depression is caused by sickness?  Only it’d have to be a sickness we can’t see for some depressed people…..”  The temptation then would be to hunt around for some suitable physical symptoms and say, “there you are!  There’s a physical cause for depression, right there!” and then hail your findings as the latest evidence in the fight against depression.


But hang on a minute….. does having a physical illness make you depressed, or does having depression make you more likely to get a physical illness?  Which causes which?  Or is there a third, currently unknown trigger, that causes both?  None of the articles I’ve read successfully convinces me that they have proved cause and effect.  There is a link between the two, that seems undisputed – when you feel ill and sore you’re likely to be low, and when you’re low it’s likely that minor aches and pains will bother you more than they would otherwise.  But cause and effect?  I don’t think so.


It’s right to treat all symptoms, be they physical or mental.  Be gentle with yourself, eat properly, take medical advice, do things to ease physical pain as much as possible, all these are blindly obvious pieces of advice.  But to dismiss what could be a severe mental illness as being solely caused by having the ‘flu last month is a ridiculous state of affairs.


I’m not for a second saying that mental illness and physical illness aren’t linked.  It’s clear they are.  But it’s impossible to say that one causes the other.   Both need treating, both need understanding, both need care and compassion, and often both come hand in hand.  But to try and fudge the issue and make mental illness somehow more acceptable simply by saying it has a physical cause is insulting.