As the country prepares to remember the 20th anniversary of the 9/11 attacks, behavioral experts warn that some people may suffer from 'anniversary reaction.'

Experts say anniversary reaction means when people experience trauma, they relive the experience on the days leading up to the anniversary. They say there are things people can do to prepare and help cope with the trauma.

"It's important not to avoid it," says Dr. Liat Jarkon, director of behavioral health at NYITCOM. "A lot of people say, 'I'm not going to put news on, I'm not going to listen,' - that's not helping. You still have these memories, and they need to come out."

MORE: Remembering 9/11 20 Years Later

Ken Fairben, of Floral Park, lost his 23-year-old son Keith Fairben in the attacks. Fairben was a paramedic with New York-Presbyterian Hospital. He died helping the injured in the North Tower. Fairben says the last conversation he had with Keith was on the phone.

"I just told him to be safe and I'll see you tonight and that's where I get emotional," says Fairben.

Fairben says the days leading up to 9/11 are difficult. He says the support from his community helps him and his family get through it.

"You have to be here to represent him," says Fairben. "Any opportunity that I can to remember Keith and talk about him, I take that opportunity."

Fairben says he continues to seek justice for his son and the nearly 3,000 people who died on 9/11.