> Of long COVID’s many possible symptoms, brain fog “is by far one of the most disabling and destructive,” Emma Ladds, a primary-care specialist from the University of Oxford, told me. It’s also among the most misunderstood.
> Long-haulers with brain fog say that it’s like none of the things that people—including many medical professionals—jeeringly compare it to. It is more profound than the clouded thinking that accompanies hangovers, stress, or fatigue. ... It is not psychosomatic, and involves real changes to the structure and chemistry of the brain. It is not a mood disorder: “If anyone is saying that this is due to depression and anxiety, they have no basis for that, and data suggest it might be the other direction,” Joanna Hellmuth, a neurologist at UC San Francisco, told me.
> And despite its nebulous name, brain fog is not an umbrella term for every possible mental problem. At its core, Hellmuth said, it is almost always a disorder of “executive function”—the set of mental abilities that includes focusing attention, holding information in mind, and blocking out distractions. These skills are so foundational that when they crumble, much of a person’s cognitive edifice collapses. Anything involving concentration, multitasking, and planning—that is, almost everything important—becomes absurdly arduous.
Like, say, autism, covid-related "brain fog" will probably have a lot of people dubiously diagnosing themselves, but it is still a real disorder with an observable set of symptoms that are being taken quite seriously by medical researchers.
I'd also remind people that it took several years of significant research resources around the world before HIV/AIDS became well understood once it spread into the western nations. Setting aside the obvious differences in severity, we've still got a brand new virus exhibiting many different behaviors in many people, and it's likely that we still have a lot to discover about its mechanisms and long-term effects.