It started with the front door.

Adrian Gomez lives with his partner in Los Angeles, where their first few days of sheltering in place for the coronavirus pandemic proved uneventful. They worked remotely, baked, took a two-mile walk each morning and refinished their porcelain kitchen sink. But then, one night, the doorknob began to rattle “vigorously,” so loud he could hear it from across the apartment. Yet no one was there.

In mid-April, Mr. Gomez was in bed when a nearby window shade began shaking against the window frame so intensely — despite the fact that the window was closed, an adjacent window shade remained perfectly still, the cats were all accounted for, and no bug nor bird nor any other small creature had gotten stuck there — that Mr. Gomez thought it was an earthquake.

“I very seriously hid myself under the comforter, like you see in horror movies, because it really did freak me out,” he said.

Now, though neither he nor his partner noticed any unexplained activity at home before this, the couple can “distinctly” make out footsteps above their heads. No one lives above them.

“I’m a fairly rational person,” said Mr. Gomez, who is 26 and works in I.T. support. “I try to think, ‘What are the reasonable, tangible things that could be causing this?’ But when I don’t have those answers, I start to think, ‘Maybe something else is going on.’”

They’re not alone … possibly in more ways than one.

For those whose experience of self-isolation involves what they to believe to be a ghost, their days are punctuated not just by Zoom meetings or home schooling, but by disembodied voices, shadowy figures, misbehaving electronics, invisible cats cozying up on couches, caresses from hands that aren’t there and even, in some cases — to borrow the technical parlance of “Ghostbusters” — free-floating, full-torso vaporous apparitions.

Some of these people are frightened, of course. Others say they just appreciate the company.

There is no scientific evidence for the existence of ghosts, a fact that has little bearing on our collective enthusiasm for them. According to a 2019 YouGov survey, 45 percent of U.S. adults believe in ghosts; in 2009, the Pew Research Center found that 18 percent of Americans believe themselves to have seen or otherwise encountered one.

Before stay-at-home restrictions in New York, Patrick Hinds, 42, left Manhattan with his husband and daughter to spend six weeks at an “adorable” cottage in western Massachusetts that they rented on Airbnb.

One night, Mr. Hinds woke up around 3 a.m., thirsty for a glass of water. He said he walked into the kitchen and saw a white man in his 50s, wearing a well-worn, World War II-era military uniform and cap sitting at the table.

“It seemed normal in the split second before I realized, Wait, what’s happening? And as I turned to look, he was gone,” said Mr. Hinds, who is the host of the podcast “True Crime Obsessed.” “It didn’t feel menacing at all. It almost didn’t even occur to me to tell my husband the next morning.”

If you were to accept the premise that ghosts are real, it stands to reason that some tension would naturally result once their flesh-and-blood roommates start spending much, much more time at home together.

John E.L. Tenney, who describes himself as a paranormal researcher and is a former host of the TV show “Ghost Stalkers,” estimates that he received two to five reports of a haunted house each month in 2019. Lately, it’s been more like five to 10 in a week.

Mr. Tenney has seen something like this before: In 1999, immediately before Y2K, he witnessed a spike in reported ghost and poltergeist activity, as well as U.F.O. sightings (which, in his experience, are also on the rise in this moment). “It does seem to have something to do with our heightened state of anxiety, our hyper-vigilance,” he said.

Mr. Tenney has no doubt that the vast majority of these cases in his inbox are “completely explainable” in nature. “When the sun comes up and the house starts to warm up, they’re usually at work — they’re not used to hearing the bricks pop and the wood expand,” he said. “It’s not that the house wasn’t making those sounds. They just never had the time to notice it.”

Or did they? Janie Cowan believes she’s been haunted since college. The ghost she calls Matthew (a “good, biblical name” chosen in the hopes it would keep him on his best behavior, explained Mrs. Cowan, who is 26) has historically made his presence known in her Nashville home through the sounds of someone running up and down the staircase at night.

The noises are “not like a house settling, or like our cat walking around,” said her husband, Will Cowan, a 31-year-old accountant. “It’s very clearly out to get attention.”

Around the same time the couple began to self-isolate in March, Mr. Cowan started to use their guest bathroom so that his wife, a home health nurse who has been picking up more night shifts during the pandemic, could sleep in without the sounds of his morning routine disturbing her.

He has found that Matthew, whom both spouses agree prefers Mrs. Cowan, doesn’t seem to appreciate these changes. On three separate occasions, while showering in the guest bath, Mr. Cowan has been unexpectedly blasted with cold water. But it wasn’t just a quirk of the plumbing: Every time, he said, he reached out to find that the hot-water nozzle had been turned off.

Madison Hill, 24, is riding out the pandemic with her boyfriend in her apartment in Florence, Italy. Ms. Hill, a writer and teacher originally from Charlotte, N.C., had always had her suspicions about her home, particularly the bathroom. There was the sense that someone was watching her, doors slamming, towels inexplicably on the floor.

A few weeks into quarantine, she woke up to find something on her nightstand that did not belong there. It was a camera lens, one she’d brought from the United States but lost when she moved in. She had long given up on ever finding it. But here it was.

Since then, other small objects, including a set of keys, have moved to strange new places inside her apartment. The reappearance of the camera lens in particular struck her as a “mischievous,” playful gesture — perhaps even a thoughtful suggestion that this could be the perfect time for Ms. Hill, who majored in film in college, to pick her old hobby back up.

Kerry Dunlap shares a one-bedroom apartment in the Ridgewood neighborhood of Queens with his girlfriend, Alexandra Cohl. Mr. Dunlap, a 31-year-old teacher, rapper and concert promoter, believes he first met their resident ghost last summer.

He saw her in the bathroom, in the middle of the night: wearing green scrubs, standing an arm’s length away from him. She appeared to be glowing. The woman vanished when he turned on the light. Mr. Dunlap knew that one of the friends the couple is subleasing from had spotted a ghost in the apartment; both agreed they’d seen an older Asian woman of small stature.

Mr. Dunlap and Ms. Cohl, a 27-year-old writer and editor, used to find themselves in a routine late-night tug of war over the too-small comforter they shared. Several weeks ago, Mr. Dunlap woke late at night to the sensation of what he assumed was Ms. Cohl adjusting the blanket at his feet to spread it evenly across the bed. When the movement stopped and he didn’t feel his girlfriend climb into bed beside him, he called out to her. She didn’t answer.

Then she came back in from the bathroom.

“It was so weird, dude,” Mr. Dunlap said. “It was so weird.” But the incident left him and Ms. Cohl with a lingering positive impression: like whoever — or whatever — it was had been trying to make the couple feel more comfortable, or to mediate a potential conflict between them before it happened.

Kurt Gray, an associate professor at the University of North Carolina at Chapel Hill, studies how we perceive and treat the minds of other entities, including animals, machines and the dead. Times of great unease or malaise, when there is an increased drive to find meaning in chaos, can lend themselves to perceived hauntings, he said — not to mention that disease itself shares certain psychological parallels with a “malevolent spirit,” creeping invisibly upon its unsuspecting victims.

This phenomenon could also be a side effect of the loneliness of our time. “In quarantine, you are physically confined and also psychologically confined. Your world narrows,” Mr. Gray said. “You’re trapped at home, you’re needing human contact — it’s comforting to think that there’s a supernatural agent here with you.”

For Danielle, a 39-year-old lawyer, isolation predates this pandemic. (The Times agreed to not use her last name, to protect her professional reputation.) She has been recovering at her home in Richmond, British Columbia, since contracting an unrelated serious illness over the winter.

She first experienced strange activity in February, she said, when she kept walking into her guest bedroom to find a particular lamp turned on, although she had no memory of leaving it that way. This happened again, and again, and again, until, on a whim, she said aloud, “Don’t turn that back on.”

The next time she entered the room, she found the ceiling light — which she never, ever switches on — blazing. On more than one occasion, she has heard the voices of a man and a woman having a conversation she couldn’t quite make out.

More recently, she was sewing face masks in the same bedroom. She had exactly enough fabric left to make one more mask, but when she briefly turned away from the ironing board where she’d just pressed the double cotton gauze, the two remaining pieces disappeared.

“It was gone,” Danielle said. “Like, in a 20-second period, gone. I went and checked the garbage pail, nothing. Checked the recycling, nothing. My fabric stash, nothing. I tore the house apart looking for these two pieces of fabric, and they have never come back.”

Danielle describes herself as a highly social person, someone whose friends and family had worried about how she’d fare cooped up all by herself. “This kind of feels like someone popping by to cheer me up, or keep tabs, or make sure that I’m not feeling alone,” she said.

If the idea of a paranormal identity can provide someone “a little bit of social sustenance” to help them endure their solitude, Mr. Gray said, then great. At least, as long as the ghost isn’t advising its hauntees to “go into emergency rooms without a mask and French kiss everybody,” he said.

Are you troubled by strange noises in the middle of the night? Do you experience feelings of dread in your basement or attic? “Don’t panic,” said Mr. Tenney, the “Ghost Stalkers” host. Take careful notes on what you observe. You may soon find a rational explanation for your fears. What if that strange noise at 2:50 p.m. every weekday is just the UPS truck clattering by?

But Mr. Tenney also offers this: One could argue that the ghost puttering around in your kitchen is not only there, but that she’s always been there. Maybe you’re what’s changed. Or maybe you’re listening more closely in the greater quiet all around us. “Perhaps we’re just now starting to notice that the world is a little bit weirder than we gave it credit for,” he said.