Depression is a mental illness that very often has physical effects. There are several potential ways in which depression affects movement, and this post will explore low energy, psychomotor retardation, and leaden paralysis. These symptoms can occur in both bipolar and unipolar depression.
Fatigue is one of the most common symptoms of depression. Fatigue can involve low energy, decreased endurance, sluggishness, and weakness, and can spill over into mental effects including decreased motivation. However, fatigue is a very non-specific symptom that can occur in the context of many other health conditions, and most healthy people will experience mild fatigue from time to time following periods of high activity.
In people who get partially but not fully better from a depressive episode, fatigue is one of the most common residual symptoms.
Among antidepressants, bupropion is more likely to be helpful with fatigue. Stimulant medications are also an option.
Psychomotor retardation involves a slowing of movement and thoughts. Often, speech is slowed, eye contact is minimal, and affect is flat (i.e. there is a lack of facial expressiveness of emotions). The slowness is objectively observable by others.
It is most common in depression with melancholic features and psychotic features.
Neurotransmission via dopamine in the basal ganglia area if the brain is thought to play a role in producing psychomotor retardation, although a number of other possibilities have been raised, including abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis, which is involved in the release of the stress hormone cortisol. You can read more about the biological possibilities here.
There is some evidence that psychomotor retardation responds well to electroconvulsive therapy (ECT). Among the different antidepressant classes, tricyclics may be most effective.
Leaden paralysis tends to occur in depression with atypical features, and about half of people with that depressive subtype experience it. Other symptoms in the cluster of atypical features include increased appetite, increased sleep, mood reactivity to positive events, and a sensitivity to interpersonal rejection.
Leaden paralysis itself involves a feeling of heaviness and being weighed down in the limbs, which produces significant fatigue. Greater leaden paralysis is associated with worse depression symptoms overall and greater chronicity.
While the biological mechanism behind this is unclear, there’s some indication it may be related to disruptions in the HPA axis or changes in the balance between left and right brain functioning.
What’s the difference?
Although there’s certainly overlap in the different ways that depression affects movement, the three are seen as discrete symptoms. It’s probably fairly safe to say that most people who experience depressive episodes as part of their illness have experienced fatigue as a symptom at one time or another. Leaden paralysis and psychomotor retardation are quite a bit less common.
I can’t speak to what leaden paralysis feels like, since I haven’t experienced it, but the key element is a feeling of lead weights in the arms and legs exerting a downward pull. This produces fatigue rather than being something that occurs as a result of fatigue.
Psychomotor retardation feels like walking through molasses. It doesn’t feel like I could go faster if only I had more energy. It’s like one of those speed-restricted vehicles—my brain has set a top speed my body can move at, and I simply can’t go any faster than that. I find the slow movement to be quite tiring, but as with the leaden paralysis, fatigue is an aftereffect rather than the cause. It affects my speech, too; my best friend has said that when he calls me, he can tell within seconds from my voice if I’m not feeling well.
The physicality of mental illness
While the difference between these three symptoms matters somewhat in terms of treatment, what I find most interesting is how physical the illness is, and in particular how much depression affects movement. These symptoms all fall under the umbrella of a major depressive episode in the DSM-5, but I wonder when/if science will be able to narrow it down a little more.
Do you experience any of these three symptoms?
- Buyudura, J.S. et al. (2011). Psychomotor retardation in depression: Biological underpinnings, measures, and treatment. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 35(2), 395-409.
- Quitkin, F.M. (2002). Depression with Atypical Features: Diagnostic Validity, Prevalence, and Treatment. The Primary Care Companion to the Journal of Clinical Psychiatry, 4(3), 94-99.
- Singh, T., & Williams, K. (2006). Atypical depression. Psychiatry MMC, 3(4), 33-39.
- Targum, S.D, & Fava, M. (2011). Fatigue as a residual symptom of depression. Innovations in Clinical Neuroscience, 8(10), 40-43.