A traumatized veteran’s combat dreams are more vivid than they have been in years.

A little girl can’t concentrate at school, terrified that her grandparents will get infected with coronavirus and die.

A person who had stopped obsessively washing his hands regresses amid a barrage of public-service messages ordering him to do exactly that.

For some of the millions of Americans with post-traumatic stress disorder, obsessive-compulsive disorder or other forms of debilitating anxiety, coronavirus is a growing mental health threat.

“It started as soon as the news that there was a new thing in the environment hit — a new virus,” said Shane G. Owens, a psychologist in Long Island, who specializes in treating anxiety. “They came in almost immediately feeling the false alarms of this and starting to see things in the environment that they saw as threatening.”

The novel coronavirus and the scary-sounding respiratory disease it causes, covid-19, have alarmed all kinds of people. More than two-thirds of Americans were “somewhat” or “very” concerned about a U.S. epidemic, according to a recent Economist-YouGov poll.

But for some of the estimated 19.1 percent of adults who have an anxiety disorder in a given year, understandable alarm can spin into a debilitating spiral.

“This is definitely a trigger for a lot of patients,” said Krystal Lewis, a clinical psychologist at the National Institute of Mental Health who treats children as well as adults. “For anyone who might have OCD or specific concerns about getting sick, once you start seeing those signs pop up even more, and the Purell is everywhere, it can be really tough.”

The stress of a new thing to worry about can exacerbate the symptoms of PTSD or trigger more frequent panic attacks in people who are prone to them. And it can be especially rough for the approximately 5 percent of adults annually who have illness anxiety disorder, formerly known as hypochondria, and are already predisposed to fear disease.

“When people suffer with anxiety, it’s because they’re believing and focusing on the lies, distortions and exaggerations in their imagination,” said Ken Goodman, a therapist who treats anxiety disorders in California and a board member at the Anxiety and Depression Association of America.

For instance, someone might perceive a few headaches and an eye twitch as a brain tumor. And the phenomenon can occur en masse as well, he said — helped along, according to everyone who spoke to The Washington Post for this story, by the relentless 24-hour news cycle.

“You just see [the virus coverage] everywhere, and it feeds people’s anxiety,” said Goodman, who wrote a self-help audio course on controlling anxiety. “So we see in bold print, ‘The first person died of the coronavirus in California!’ and it sounds terrifying. But so far 20,000 people have died of the flu in the United States this year, but people aren’t anxious about the flu because it’s not being reported endlessly.”

Of course, not everyone who has an anxiety disorder — or even illness anxiety — is worried about this particular virus. Goodman said just one of the roughly 60 anxiety patients he treats each month has expressed a fear of the virus so far, a woman with OCD. (Another patient, a man who has a fear of vomiting, was concerned until he found out that nausea is not a common covid-19 symptom.)

The flip side is that some mental health experts think coronavirus fears may cause people with anxious tendencies to topple into a full-blown illness.

“What is likely to come of this is a lot of people who have underlying anxiety disorders — they’re going to start experiencing those,” Owens said. “We’re not only going to end up with lots of covid cases, we’re going to end up with lots of anxiety disorders out of this as well.”

So how do you tell if you, or someone you know, has made the leap from garden-variety uneasiness to a spiral that requires intervention?

“You’re having an anxiety reaction if you’re anxiety is increasing in frequency and intensity, and if it’s invading your ability to function,” said Charles Marmar, chair of the department of psychiatry at New York University’s Langone Heath and a specialist in studying and treating PTSD. “You’re having trouble changing the channel from the ‘worry channel’ to focusing your mind on friendships, love, work, hobbies, etcetera.”

Fortunately, the advice experts give to a person with a diagnosed anxiety disorder and to a person who is just freaked out because they’ve binged too much cable news is largely the same:

  • Maintain your routines as much as possible.
  • Avoid crowds, but don’t isolate yourself.
  • Sleep, because it’s good for your immune system.
  • Eat healthy food; don’t stress-eat junk.
  • Don’t drink too much alcohol — or coffee.
  • Exercise: It’s calming and may boost immune function.
  • Get news only from reliable sources (such as the one you’re reading right now) and don’t become absorbed in the coverage for long periods of time.
  • Take breaks. Play a game. Watch a movie (but not “Contagion”). Take a yoga class. Try a meditation app. Anything that will get your focus off the blather.
  • If all of these fail, seek help. Many websites have resources for anxiety disorders, including the Anxiety and Depression Association of America and the American Psychiatric Association. Major academic medical centers have stress and anxiety departments. And many therapists offer counseling via phone or video conference so patients don’t need to leave their homes.

“All of those things are practically useful,” Marmar said, “but probably even more important, they confer a sense of control when we feel more helpless.”