This episode contains strong language.Ivan Agerton of Bainbridge Island, Wash., was usually unflappable. A 50-year-old adventure photographer and former marine, he has always been known to be calm in a crisis.Soon after testing positive for the coronavirus this fall, he began experiencing psychosis. He spent Christmas in a psychiatric ward.Today, we hear from Ivan and look at the potential long-term neurological effects of the Covid-19Guest: Pam Belluck, a health and science reporter for The New York Times. Sign up here to get The Daily in your inbox each morning. And for an exclusive look at how the biggest stories on our show come together, subscribe to our newsletter. Background reading: A small number of coronavirus patients have reported severe psychotic symptoms. Most had no history of mental illness.Some people experiencing long-term Covid-19 symptoms are feeling better after getting the vaccine, but it is too soon to tell whether the shots have a broad beneficial effect on patients with continuing issues.For more information on today’s episode, visit nytimes.com/thedaily. Transcripts of each episode will be made available by the next workday.