Back in the 1980s, there was a public service announcement on TV that you may remember — or may have seen on YouTube. A guy in a kitchen held up an egg and said, "This is your brain." Then he cracked the egg into a hot frying pan, and said, "This is your brain on drugs." One year into this pandemic, your brain might be feeling a bit like that egg: Fried. "Everything is so much harder," said Stephanie Johnson, a client relationship executive who lives in Toronto. "I don't have the motivation that I used to have. I don't have the efficiency that I used to have." "Defeated" is how Vas Smountas, a freelance graphic designer, describes it. Also living in Toronto, she describes herself these days as "tired, defeated, foggy, unmotivated." And research suggests those feelings are not uncommon right now,...