A rapid rise in the trolling of US writers and journalists has led civil liberties group PEN America to create a “field guide” for dealing with the problem. It follows a survey of writers that found online harassment was posing a “significant threat to free speech”.

The survey revealed that two-thirds of trolled writers had responded to the abuse by refraining from publishing their work and deleting their social media accounts. They also said they feared for their personal safety as a result of the abuse. Over a third of respondents – who include leading US authors and journalists – said trolling had led them to avoid controversial topics in their writing.

Harassment of writers ranged from criticism of their viewpoints to attacks based on race, gender and sexual orientation, with those belonging to the most marginalised communities or those speaking out about injustice facing the most extreme online hate. Playwright and music blogger who trolled teenagers she had worked with through a queer youth programme: “He was coming after them on social media, being like: ‘You’re so ugly. Are you a man or a woman? What are you?’ Calling them disgusting. In that case, it was extra terrifying because these are young people that I worked with in a suicide-prevention capacity.”

Announcing the guide to combating trolls, Suzanne Nossel, PEN America chief executive officer, said: “Online harassment poses a clear threat to free expression, as evidenced by the results of our survey. When certain voices are muzzled, when people choose not to write about topics that matter and when they remove themselves from the public debate, everyone loses.”

Nossel said PEN America is “especially disturbed by the ways in which online harassment affects their work”. She added: “Journalists and writers whose web presence is a professional imperative can’t be left defenceless in the face of rampant digital intimidation, provocation and vitriol when they dare to stick their heads above the parapet.”

The manual provides advice, guidance and resources on cyberstalking, doxing and hate speech. The charity said it was intended to “fortify” writers and journalists with the best available means to protect themselves and secure their freedom to write.

Bethany Mandel, a New Jersey-based conservative columnist and Trump opponent, said she received a deluge of abuse after she referenced Trump’s anti-semitic online following. “Suddenly I was getting 100 tweets a minute,” she told PEN America. “I’d open my phone at my kids’ playgroup and see a picture of myself in a gas chamber. My biggest issue at the time was determining if [something] was actually a threat and, if so, what to do about it.”

An Iranian author interviewed by the charity and referenced only as K, to protect her identity, said online threats had made her fear for her safety. “Because I’m also partially disabled, it can make me feel all the more vulnerable,” she said. “At times, I’ve said no to certain publications because I feel that many aspects of my identity have lured harassers and I simply can’t take anymore.”

Despite the threats, K was determined to remain on social media. “I think Twitter has been a great space for the most part. As it is full of women of colour I feel much safer existing there,” she said. But she added: “It is also where Nazis are allowed to roam for way too long.”

The manual calls on employers, tech companies and law enforcement agencies to play a stronger part in the fight to stop online abuse of writers. “In the digital age, all writers and publishers of online content are vulnerable and susceptible to web attacks,” Laura Macomber, PEN America journalism and press freedom project manager, said.

“Those facing online harassment must make an impossible decision: engage and put themselves at risk, or disconnect and miss out on important online discourse,” she added. “Our goal is to equip writers and their allies – especially those whose livelihoods are at stake – with resources to push back against online hatred and harassment, so they can continue to do their jobs.”