From his episode:
“Before you guffaw and dismiss this, let’s review what we’ve learned about acute stress in previous episodes. Chronic acute stress can produce definite physical symptoms, and they are — all down the line — exactly the symptoms reported by the diplomats. Sleeplessness, anxiety, nausea, headaches, fatigue, cognitive impairment, etcetera. The reported symptoms began immediately after Donald Trump had been elected President and vowed to crack down on US-Cuban relations. This placed greatly increased stress on the American diplomats.
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This also explains why it happened only to Americans (plus a few Canadians) and not to the local Cubans in the same houses and buildings. We would expect a mass psychogenic event to not affect the Cuban neighbors and employees. As Cubans, they have no reason to think they’d be targeted, and they lack the stress of being from the enemy country.
It’s a solid explanation with numerous precedents from recent history. It fits nicely with Occam’s Razor, in that it’s an ordinary explanation that does not require us to make any changes to our understanding of physics or biology. Of course we don’t know that this is in fact what happened, but unless some evidence emerges showing a physical cause, it’s the best supported explanation. And that, my friends, is how we do science.”