Got widespread chronic pain? There’s a respectable chance you could be identified by your genes alone.
The largest study of the genetics of chronic pain patients to date found 76 genes that are independent risk factors for it (see Johnston). Interestingly, almost half of these genes are also risk factors for severe depression, and there’s also substantial genetic overlap between chronic pain and
- body-mass index,
- rheumatoid arthritis, and
- post-traumatic stress disorder,
chronic pain may be caused by a common genetic defect leading to low levels of the neurotransmitter serotonin (see Khoury et al.).
A common genetic defect, mind you. Not rare. At ten percent of the population, it’s about five times more common than red hair.
What does a chronic shortage of serotonin do?
It has to be about more than just serotonin because I started taking SSRIs (selective serotonin reuptake inhibitors) in 1986 and my pain still got worse and worse. Even at the maximum dosage of such medications, they did not come close to relieving my pain.
it appears to exaggerate bodily sensations — “somatic awareness” — which is rich soil for chronic pain to take root in.
Patients with unexplained chronic widespread pain are notorious for having many, many other odd complaints — uncomfortably strong sensations of all kinds. Indeed, the pain often just seems to be the tip of a iceberg of abnormal sensations.
Amped up somatic awareness is a bizarre phenomenon.
I can vouch for this. I always assumed it’s just because I have EDS and that my defective and frail connective tissue is vulnerable to all kinds of pressures. My ears are sensitive to sound, my eyes are sensitive to light, and I’m sure my body is unusually sensitive to pain as well.
It’s hard for anyone — patients and pros alike — to believe that there is an obscure organic cause for totally indiscriminate sensory excess.
Science news like this serotonin story is catnip for patients beseiged by suspicion that their troubles are all in their heads. Their own suspicions as well as the condescending assumptions of so many healthcare professionals.
everyone, for decades, has been underestimating the sheer number of pathologies that can make people hurt for no obvious reason.
People almost certainly seem “crazy” more often than they actually are.
When my headache pain gets extreme enough for long enough it definitely makes me crazy. How else would you describe someone who whacks her head against a solid wood door just to momentarily create a different extreme pain as a distraction?
Pain is fundamentally a threat detection system.
This is why chronic pain is like having an alarm stuck in the “on” position and not being able to turn it off.
The brain uses all kinds of sensory data and contextual clues to decide what hurts and how much.
Somatic awareness gives the brain a lot more sensory noise to try to interpret, which could throw a monkey wrench into the pain system.
Excessive sensory data is not inherently threatening, but it could quickly become threatening when challenged by a mysterious illness or alarmingly stubborn back pain.
For many years now, anti-depressant medications have been used, with some success, to treat conditions related to somatic awareness, like fibromyalgia. And that tends to reinforce the stigma against these patients. Successfully treating chronic pain with a pill for depression has an “optics” problem. Many have assumed that it must work because pain is just a complication of the real problem: depression.
Argh! Yes, patients assume they’re being told the pain is just in their imagination because they’re depressed.
I suspect that chronic emotional pain and chronic physical pain egg each other on making each worse and worse.
While I believe that I notice my pain more when I’m miserable with depression, I also think my constant pain makes me depressed – who wouldn’t be when you can no longer do so many things that used to be enjoyable?
Maybe anti-depressants are more relevant to somatic awareness and chronic pain than they are to depression, because they can actually treat a well-defined pathology — unlike their generally lacklustre performance with depression.
That would be impressive irony.