The term ‘sickness syndrome’ refers to a constellation of non-specific symptoms that develop in connection with many ailments, especially infections. Simply stated, when you get an infection you feel lethargic, fatigued, sleepy, and somewhat depressed. You feel sick.
Fibromyalgia results in those same symptoms, not (of course) because it’s caused by a ‘bug’, but fibromyalgia might trick your brain into thinking you’ve got one doozy of an infection – an infection that never seems to go away.
To see how fibromyalgia does that, and the results of such trickery – read on.
Your brain does what it’s told.
Basically, when your body senses that you have a bacterial or viral infection, it sends a message to your brain: “Hey, there’s an infection out here, please make the person act sick so that we can get better faster.”
“Will do!” says the brain And it sets to work making you feel lethargic, fatigued, sleepy and depressed.
It’s good for you.
It’s pretty easy to see how being sleepy might help you heal faster (you go to bed!) And of course being fatigued means you’re less likely to start any new projects (so that energy can instead be used to fight infection.) The same goes for depression. When depressed, you’re more likely to stay home alone (and heal) than go to a party (where you’ll both waste energy and be likely to spread the infection.)
So ‘sickness syndrome’ makes sense. It’s good for you (assuming you actually have an infection.)
But what if the message is wrong?
What if your brain is doing what it’s supposed to – based on the message its receiving – but that message is wrong?
Ouch! Sickness syndrome is no longer ‘good for you’. In fact it’s bad for you – really bad. Especially if that same misleading message never stops – “we’re infected, we’re infected, we’re infected….”
That’s what seems to happen in fibromyalgia.
To understand how and why fibromyalgia sends that message to your brain, we need to take a quick look at the role played by cytokines.
Cytokines are the messengers of the immune system.
As described in the first publication below, infections cause the release of pro-inflammatory cytokines. Those travel to your brain where, in response, the brain then makes even more pro-inflammatory cytokines. The result is sickness syndrome.
The problem is, your brain can’t tell whether the message it’s receiving is accurate or not. It ‘assumes’ that, yes, there really is an infection, that’s why I’m getting bombarded with all these cytokines, so I really should make this person act sick. Oddly enough, your brain can’t think for itself. It just does what it’s told.
Both publications referenced below discuss sickness syndrome in relation to infection and inflammation. Fibromyalgia isn’t an infection, and it may not be (strictly speaking) an inflammatory condition. But it seems having fibromyalgia means, among other things, that your body starts producing too many pro-inflammatory cytokines. That might happen as a result of whatever causes fibromyalgia, or it might be the actual cause of fibromyalgia.
Either way, the result is the same. Fibromyalgia means your body sends the same (wrong) message over and over. Pro-inflammatory cytokines keep telling the brain, “There’s an infection, make this person act sick.” And the brain does what it’s told.
If you’re sick for a long time (fibromyalgia) then it seems your brain starts trying even harder (to make you sick.) “Argh, (says the brain) we’re not getting better. I’m still being getting hit with all these cytokines – so the infection must still be there. I should make this person really, really fatigued and even more depressed. Maybe then we’ll get better.”
That’s basically what the second publication is saying. Depression results when your body constantly sends pro-inflammatory signals to the brain. Regardless of whether those signals are ‘right’ (you have a chronic infection) or wrong (you have fibromyalgia) – the result is the same. You are very likely to become depressed. It’s not a weakness, or a flaw, or something that you can just ‘snap out of’. Your brain is doing what your body is telling it to do – it’s making you depressed.
Summary of the Abstract
‘Sickness syndrome’ is beneficial during an infectious episode.
The process is triggered by pro-inflammatory cytokines that are produced by peripheral phagocytic cells after those cells come in contact with invading micro-organisms. The peripheral immune message is then relayed to the brain, where it results in the production of pro-inflammatory cytokines in macrophage-like cells and microglia in the brain. As understanding of the cellular and molecular components of this pathway increases, understanding of brain disorders, including depression, may also increase.
From inflammation to sickness and depression: when the immune system subjugates the brain.
In response to a peripheral infection, innate immune cells produce pro-inflammatory cytokines that act on the brain to cause sickness behavior. When this continues for a long time, such as during systemic infections, cancer or autoimmune diseases, the ensuing immune signaling to the brain can lead to an exacerbation of sickness and the development of symptoms of depression. This might be why there is a greater incidence of clinical depression in physically ill people.