What does the gate control theory of pain have to do with a mental health blog? Well, co-occurring mental illness and chronic pain are remarkably common. For example, among people with fibromyalgia, over 50% experience depression. The rates of anxiety disorders are also over 50%. People with depression and anxiety disorders are also at increased risk to develop a pain disorder.
The gating process
So, how does pain actually work? Pain receptors (called nociceptors) get stimulated, and that message travels to the spinal cord and up to the brain. It’s not as simple as that, though. There is a gating process that determines which pain signals get through, and that’s the basis of the gate control theory, which was initially developed in 1965.
The gating action happens at a part of the spinal cord called the dorsal horn. Several kinds of nerves converge here and try to pass on their signals. Small nerve fibres carry pain signals, while large nerve fibres carry other sensory information. Then there are inhibitory interneurons connecting to both large and small fibres, as well as projection neurons that travel on up to the brain.
The inhibitory interneurons play the role of gates. If there is a strong pain stimulus, it closes the gate to the large fibres and their sensory info, allowing the pain signals to pass through and get transmitted up the spinal cord. If there’s a stronger stimulus from the large fibres, that sensory signal gets passed along rather than the pain signal.
Factors that affect pain perception
This may explain why acupuncture is helpful (albeit not in the way it’s claimed to work). It stimulates sensory nerves without producing pain, which can help to drown out some of the pain signals. Transcutaneous electrical nerve stimulation (TENS) accomplishes the same purpose.
The gates are also affected by signals sent from the brain down the spine, which introduces a number of other factors that can influence the perception of pain. Stress, tension, inactivity, and increased focus on pain can open up the gates to let pain signals through. Catastrophizing around pain promotes hypervigilance and heightens the focus on pain, which leads to more pain signals being transmitted to the brain. Relaxation, good mood, physical activity, and focus on activities rather than the sensation of pain have the opposite effect. Cognitive behavioural therapy (CBT) for pain likely works at least in part by affecting this aspect of the gate control theory.
What I find most interesting about this theory is that it suggests that the most effective approach to managing chronic pain is multi-pronged. Sure, medications can affect the transmission of pain signals, but the other ways we stimulate our bodies and what we do with our minds matter as well – and not just in a dismissive “just choose to be happy” kind of way, but in a logical, biologically based way.
Do you have a co-occurring mental illness and chronic pain? Does gate control theory fit with how you conceptualize your pain disorder?
You may also be interested in the post CBT for Chronic Pain.
References
- Freudenrich, C. (n.d.). How pain works. How Stuff Works.
- Hooten, W.M. (2016). Chronic pain and mental health disorders. Symposium on Pain Medicine, 91(7), 955-970.
- VA Health Care Center for Integrated Healthcare. (2013). The gate control theory of pain.
- Wikipedia: Gate control theory
Interestingly this is me at the moment. Though my anxiety and depression are current well managed I am under investigations for neuralgia and stiffness/pain/numbness in my hands, wrists and lower arms. I never associated the two together. It’ll be interesting to find out more! Xx
Hopefully it doesn’t take too long to figure out what’s going on. xo
Yep. One more scan and another appt, then hopefully I’ll have some more info to work with. X
Oh good!
The mind body connection is real. It affected me in the negative way; when my mood is bad or I worry a lot, I tend to feel more pain. Which now I translate as ‘my body is speaking to me and I need to listen’. The gates are open then and information is coming through.
With my teeth grinding problem (the mouth guard is in delay!!) I really try to relax my jaws and the mind before I go to bed. I’ve heard that I grind shorter periods now but more more often 🙄 But the pain is less prominent 🙂
That bodes well for when the mouth guard is available.
I’ve been dealing with chronic pain since the age of 19 and even before that I had issues. I do think the trauma and abuse of my childhood has a lot to do with my health problems that I later developed. I have noticed over and over that the pain is worse and the flare ups come more often whenever I am stressed and depressed.
Sucks how trauma can hijack the whole body.
yeah, it’s a gift that keeps on giving 🙁
I think what’s interesting is how the body builds up a tolerance to pain, or how some people seem to handle it better than others. On a cellular level, I wonder why that is.
That would be very interesting to know.
I get it completely – I have Transverse Myelitis which means I have lesions inside my spine at both C5-6 and L-5. So messages don’t get from my lower body to the brain and vice versa – that’s what makes my movement so difficult.
I can and have had many spills with hot coffee and not noticed the burning until I go to wash, change my clothes etc (I’m too busy cleaning the table, chair, laptop etc). I then have huge blisters and have to go to A&E.
One time, I was on my knees, trying to clean my oven with one of those wonder sprays. I hadn’t noticed that it had seeped through my jeans – again until I was in the shower and saw this 6 x 4 inch thick black scab (sorry if you’re squeamish). It was too late to do anything or go to hospital as the burn had already scabbed over – I still have that big fat scar. In fact, I’m covered in them 🙂
So I don’t feel certain pain or cold but I still have nerve and muscle pain?
Kind of like the worst of both worlds.
Yep – nothing else to do but get on with it,
I have lupus and depression but I’m not sure if the depression is because of my lupus or because of the trauma from my childhood.
One interesting thing I came across was that many people who have lupus end up with something called neuropsychiatric systemic lupus erythematosus (NPSLE) and the most common symptoms include headaches, depression, and general cognitive decline.
I think sometimes it’s hard to filter out what is caused by mental health issues and what is caused by a chronic disease. Like if I wake up in the morning with aching joints and an overall crappy feeling is that because of the lupus (which definitely can happen) or is it because I’m feeling extra sensitive from a horrible night filled with nightmares? Maybe it’s one or the other or maybe it’s an accumulation of both.
I try my hardest not to overwhelm myself with my lupus symptoms (nor do an excessive amount of research on it) because it definitely makes things worse if you focus on the pain and all of the things that can go wrong. I just try my best to push it off to the side even though sometimes it demands to be acknowledged. And the depression? Well, that waxes and wanes depending on the day and how things are going.
I’ve heard of NPSLE. And there does appear to be a link between inflammation and depression more generally. Fascinating how intertwined things are.