Mental health

The Biology of Psychomotor Retardation

Why did I get slowed down? The biology of psychomotor retardation in depression

While psychomotor retardation (slowing of movement and thoughts) has long been recognized as a symptom of depression, I think it’s probably not on the average person’s radar when they think about depression. The biology of psychomotor retardation is also poorly understood.

What psychomotor retardation is

Psychomotor retardation (PMR) is most often associated with the melancholic subtype of depression. It encompasses a range of disturbances, including:

  • slowed movements that are objectively observable by others
  • lack of facial expressiveness (“flat affect”)
  • decreased eye contact
  • speech changes: decreased volume, slow and monotonous speech with increased pauses, delayed verbal responses
  • slumped posture
  • reduced mobility in trunk and proximal limbs (upper legs and arms)
  • increased self-touching

This has always been a pretty significant element in my own illness, and is currently what’s most disabling. So why am I so slow?

Science doesn’t really know.

Possible biological mechanisms

Dopamine appears to be the major neurotransmitter involved, although norepinephrine and GABA may play a role as well. Serotonin may also play a role in the cognitive aspect. The dopamine factor is likely why taking a stimulant (dextroamphetamine) is helpful for my PMR.

Structural changes in the basal ganglia are thought to play a role. It’s an area of the brain that has a number of functions, including being involved in movement. Changes in dopamine receptors in the basal ganglia are thought to be the cause of tardive dyskinesia from antipsychotics. Parkinson’s disease affects this same region, and it’s been suggested that there could be some form of shared underlying pathology.

Other structural changes have also been suggested, including a correlation between white matter hyperintensities (a type of brain lesion) and PMR.

Decreased blood flow to several areas of the brain, including the prefrontal cortex, has been observed in people with psychomotor retardation.  Decreased blood flow to the supplemental motor area has also been observed. Difficulty generating signals to the motor cortex region has also been suggested as a potential contributing factor.

There’s some indication that the hypothalamic-pituitary-adrenal (HPA) axis is involved.  The HPA axis is how the brain and the adrenal glands communicate to regulate the release of the stress hormone cortisol.

One major type of brain circuit runs from the cortex (the outer, most advanced part of the brain) to the striatum (which is in the basal ganglia region and is involved in motor activity, and then swings by the thalamus before returning back to the cortex. Structural and functional imaging studies in people with PMR have shown abnormalities in these circuits. The thalamus is part of the limbic system, and abnormal signals originating in that part of the brain may tie together the aspects of cognition, emotion, and movement.

So what now?

Clearly, science hasn’t figured out much yet. And in terms of research priorities, I suspect it’s relatively low on the list.

My hope is that at some point, a researcher somewhere will get an AHA moment and figure out what’s really going on with the biology of psychomotor retardation. More than simple scientific curiosity, that matters because the current bunch of treatments available aren’t all that effective. Perhaps if it was better understood, a more targeted treatment could be identified to add on top of the usual depression treatment options.

Until then, I’ll be that person moving only slightly faster than a snail.

Is this a symptom that you’ve dealt with as part of your own illness?

Sources

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46 thoughts on “The Biology of Psychomotor Retardation”

      1. Now if only I could give you some of the restless energy, and you give me some of the psychomotor retardation – then we’ll both hopefully be in better shape!

  1. So this may have a physical cause rather than being part of a psychological/emotional/trauma cause…I don’t know if that is heartening or not – usually with a physical cause one can seek a physical medical solution – unless of course no one is looking for it. As I was reading the list of how it manifests I was indeed thinking of Parkinson’s. How very complicated…

    1. There may be some physical things contributing as well, but for me, the timing of it and fluctuations in severity are very clearly linked to the depression.

  2. I had never heard of this but can certainly identify it not only when I’m depressed, but just in general with my ability to detach and slow things down. I also think Psychomotor Retardation would have been an awesome name for an 80s metal band. It wouldn’t fly these days.

  3. I can become very slow in moving, but I don’t know if that’s what you mean. My reactions are slowed down definitely. I can almost ‘feel’ my brain processing words, it feels like a thick fog and then I need to answer something. The whole process makes me forget the question and I stare for a while. Unfortunately that’s not an enough answer, so the whole process begins again.
    It can take so much energy to just go through the motions. For me it’s a sign that I really need to take a deep rest and reevaluate the things that are happening and my sleeping schedule. I don’t have it all the time, just when I’m really tired and confused. It’s never alone in my body, it’s always together with the cognitive side too.
    I adapt but I’m scared in traffic because I can’t react in a normal way which makes it dangerous sometimes. Does this sound like psychomotor retardation or I am just tired then?

    1. Sounds like more than fatigue to me. I’ve definitely got a cognitive aspect too, but I find it harder to self-evaluate the severity because I can’t remember what it felt like for my brain to work properly. Whereas with the physical component, I find it a lot easier to evaluate objectively.

      1. I feel a very distinct difference and it is obvious to my surroundings too.
        I never realized that that came with the ‘package’ too. But like you described all the brain areas that are involved, it’s not that surprising that there are so many different areas in daily life that are being touched.
        Very interesting post, a topic that deserves more attention.

  4. I haven’t experienced what you describe, well not that I noticed. My most severe reaction to the depression is the literal inability to get out of bed at all. It’s not that I CAN’T, physically, it is more that I don’t want to and the energy/motivation to do so is just not there. I am possibly biased on what PMR IS, because I had a parent who had polio as a child and was neurologically impacted. His cognitive function was fine, but physically? His reflexes didn’t work properly so he could never drive a vehicle; his speech was slow and he sounded a bit ‘slow’ (he wasn’t); and physically he moved very very slowly. People mistook him for being drunk because he couldn’t walk a straight line. That’s the picture I have in my head of what you’re describing. I’ve never had that and I hope fervently I never do. It sounds awful. I hope they can find a reliable solution, because chronic depression, all by itself, is enough for one plate in my opinion. No adding to it!

  5. A lot of the time I feel lack of energy which I think makes me slower, but it is also my whole thought process. Like if someone talks to me it takes ages for my brain to acknowledge their words, come up with a response, and then say that response, sometimes at the worst of times, I never even manage to get the response out because my brain can’t register wits been said and make an appropriate response. I also struggles to keep my eyes properly open and it almost feels as if I am being weighed down everywhere I go, and I don’t really feel alive

  6. Thank you Ashley, your expert skill in teasing out the complexities of mental subject, never cease to amaze me. Thank you for another well presented topic. I thoroughly enjoy your posts. Bless you!

  7. This is something I haven’t come across actually, but it was in interesting read!! I will research this further for sure 🙂

    Feel free to read some of my blogs 🙂

  8. Interesting. Everything seems to have a solid biological/scientific explanation ~ in the old days, we would call people “lazy” or “unmotivated.” I was depressed during my first and only semester at away-university and I distinctly remember a guy commenting to me how slow I walked. I didn’t even know him! He just felt the need to annoy a stranger. At the time, I was hugely embarrassed, thinking he was ALSO commenting on my weight (I was maybe 10 pounds “too heavy” at a time when girls were supposed to be skinny). Anyway, more recently during this lockdown I’ve been feeling down and I am slower too

  9. Sounds really debilitating to deal with on a daily basis! I myself have never dealt with psychomotor retardation as such, though typically the lower my mood is, the lower my energy so I am often slow and sluggish, but it’s milder and not so disabling, so doesn’t really pose a problem in itself.

  10. That sounds like it can be frustrating to deal with. I hope scientists have that AHA moment too, so you can get some symptom relief! I don’t experience psychomotor retardation usually (although sometimes my brain feels foggy and my response time is slow) – my biggest physical symptom of depression is just fatigue.

  11. This is very interesting. Thanks for sharing! I have experienced this in my illness, but not super often. I’ve had more the opposite feeling when manic. I feel like everything around me is super slow – time, people, movements, and others.

    I’m sorry you are going through this and it is so debilitating. It’s so hard dealing with these other symptoms on top of what we already deal with.

  12. I have had hypoglycemia for half of my life. The slowness you describe is certainly part of it when I am experiencing symptoms, which is daily, but not all day long.

  13. No clue how I overlooked this blog post, but better late than never!!

    I think I do suffer from it on occasion, especially if I’m depressed and/or hormonally challenged. I don’t even think I’m aware of it. Others would be. I just go into a haze.

    I’ve been reading in my memory book that depressants like alcohol slow you down. Could there be an inherent link between depression and slowness? Because think of the opposite–mania–and how fast manic people are. But I know what you mean! If they can figure out the physiological cause, it would enable better treatment options! I’m wondering about alertness aids offhand, or “uppers”, but I know you already take those, so… I hope science can find a cure! 🙂

    1. Alcohol is a central nervous system depressant, which is a different thing from depression the mental illness, although that commonly gets confused in articles online.

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