Doesn't mention the mysterious sleeping sickness epidemic of the early 20th century [0]. I learned of it through Oliver Sacks' writings. Survivors were afflicted by a permanent neurological change:

> They would be conscious and aware – yet not fully awake; they would sit motionless and speechless all day in their chairs, totally lacking energy, impetus, initiative, motive, appetite, affect or desire; they registered what went on about them without active attention, and with profound indifference.

I can't help but be reminded of the current wave of chronic fatigue. I feel that modern doctors are too... hubristic? to find novel treatments for this like L-dopa.

[0]: https://en.m.wikipedia.org/wiki/Encephalitis_lethargica